Science.gov

Sample records for action contractor rac

  1. 77 FR 11127 - Medicaid Program; Announcement of Medicaid Recovery Audit Contractors (RACs) Contingency Fee Update

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... FR 57808), we published a final rule entitled: ``Medicaid Program; Recovery Audit Contractors.'' This... Medicaid RAC programs. In the September 16, 2011 Federal Register (76 FR 57808), we published a final rule... Recovery Audit Contractors (RACs) Contingency Fee Update AGENCY: Centers for Medicare & Medicaid...

  2. 75 FR 69037 - Medicaid Program; Recovery Audit Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-10

    ...; Recovery Audit Contractors AGENCY: Centers for Medicare & Medicaid Services (CMS), HHS. ACTION: Proposed... State start-up, operation and maintenance costs of Medicaid Recovery Audit Contractors (Medicaid RACs... establish programs in which they would contract with 1 or more Recovery Audit Contractors (Medicaid RACs)...

  3. 10 CFR 707.17 - Permissible actions in the event of contractor noncompliance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Permissible actions in the event of contractor... Procedures § 707.17 Permissible actions in the event of contractor noncompliance. Actions available to DOE in the event of contractor noncompliance with the provisions of this part or otherwise performing in...

  4. 77 FR 7108 - Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors Regarding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ... of Federal Contract Compliance Programs 41 CFR Part 60-741 RIN 1250-AA02 Affirmative Action and...) proposes revising the regulations implementing the nondiscrimination and affirmative action regulations of... rule entitled, ``Affirmative Action and Nondiscrimination Obligations of Contractors and...

  5. 10 CFR 707.17 - Permissible actions in the event of contractor noncompliance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Permissible actions in the event of contractor noncompliance. 707.17 Section 707.17 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.17 Permissible actions in the event of contractor noncompliance. Actions available to DOE...

  6. 10 CFR 707.17 - Permissible actions in the event of contractor noncompliance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Permissible actions in the event of contractor noncompliance. 707.17 Section 707.17 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.17 Permissible actions in the event of contractor noncompliance. Actions available to DOE...

  7. 10 CFR 707.17 - Permissible actions in the event of contractor noncompliance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Permissible actions in the event of contractor noncompliance. 707.17 Section 707.17 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.17 Permissible actions in the event of contractor noncompliance. Actions available to DOE...

  8. 10 CFR 707.17 - Permissible actions in the event of contractor noncompliance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Permissible actions in the event of contractor noncompliance. 707.17 Section 707.17 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.17 Permissible actions in the event of contractor noncompliance. Actions available to DOE...

  9. 75 FR 8397 - Notice of Utah's Resource Advisory Council (RAC)/Recreation RAC Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-24

    ... Bureau of Land Management Notice of Utah's Resource Advisory Council (RAC)/Recreation RAC Meeting AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Utah's Resource Advisory Council (RAC)/Recreation... Management's (BLM) Utah Resource Advisory Council (RAC)/Recreation RAC will meet as indicated below....

  10. 75 FR 43116 - Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-23

    ... of Federal Contract Compliance Programs 41 CFR Part 60-741 RIN 1250-AA02 Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors; Evaluation of Affirmative Action Provisions Under... public to provide input on how OFCCP can strengthen the affirmative action requirements of...

  11. 28 CFR 115.177 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Corrective action for contractors and volunteers. 115.177 Section 115.177 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Lockups Discipline § 115.177 Corrective action...

  12. 28 CFR 115.177 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Corrective action for contractors and volunteers. 115.177 Section 115.177 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Lockups Discipline § 115.177 Corrective action...

  13. 28 CFR 115.177 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Corrective action for contractors and volunteers. 115.177 Section 115.177 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Lockups Discipline § 115.177 Corrective action...

  14. 28 CFR 115.277 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Corrective action for contractors and volunteers. 115.277 Section 115.277 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Community Confinement Facilities Discipline §...

  15. 28 CFR 115.277 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Corrective action for contractors and volunteers. 115.277 Section 115.277 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Community Confinement Facilities Discipline §...

  16. 28 CFR 115.377 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Corrective action for contractors and volunteers. 115.377 Section 115.377 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Juvenile Facilities Discipline § 115.377 Corrective...

  17. 28 CFR 115.277 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Corrective action for contractors and volunteers. 115.277 Section 115.277 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Community Confinement Facilities Discipline §...

  18. 28 CFR 115.377 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Corrective action for contractors and volunteers. 115.377 Section 115.377 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Juvenile Facilities Discipline § 115.377 Corrective...

  19. 28 CFR 115.377 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Corrective action for contractors and volunteers. 115.377 Section 115.377 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Juvenile Facilities Discipline § 115.377 Corrective...

  20. 28 CFR 115.77 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Corrective action for contractors and volunteers. 115.77 Section 115.77 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Adult Prisons and Jails Discipline § 115.77 Corrective...

  1. 28 CFR 115.77 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Corrective action for contractors and volunteers. 115.77 Section 115.77 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Adult Prisons and Jails Discipline § 115.77 Corrective...

  2. 28 CFR 115.77 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Corrective action for contractors and volunteers. 115.77 Section 115.77 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE ELIMINATION ACT NATIONAL STANDARDS Standards for Adult Prisons and Jails Discipline § 115.77 Corrective...

  3. NADPH oxidase-mediated Rac1 GTP activity is necessary for nongenomic actions of the mineralocorticoid receptor in the CA1 region of the rat hippocampus.

    PubMed

    Kawakami-Mori, Fumiko; Shimosawa, Tatsuo; Mu, Shengyu; Wang, Hong; Ogura, Sayoko; Yatomi, Yutaka; Fujita, Toshiro

    2012-02-15

    Mineralocorticoid receptors (MRs) in the central nervous system play important roles in spatial memory, fear memory, salt sensitivity, and hypertension. Corticosterone binds to MRs to induce presynaptic vesicle release and postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor aggregation, which are necessary for induction of long-term potentiation under psychological stress. On the other hand, cognitive dysfunction is an important problem clinically in patients with hypertension, diabetes, and cerebral infarction, and all of these conditions are associated with an increase in reactive oxygen species (ROS) generation. Oxidative stress has been shown to modify the genomic actions of MRs in the peripheral organs; however, there have been no reports until now about the relation between the nongenomic actions of MRs and ROS in the central nervous system. In this study, we investigated the relationship between ROS and the nongenomic actions of MR. We examined the nongenomic actions of MR by measuring the slope of the field excitatory postsynaptic potentials and found that ROS induced an additive increase of these potentials, which was accompanied by Rac1 GTP activation and ERK1/2 phosphorylation. An NADPH oxidase inhibitor, apocynin, blocked the nongenomic actions of MRs. A Rac1 inhibitor, NSC23766, was also found to block synaptic enhancement and ERK1/2 phosphorylation induced by NADPH and corticosterone. We concluded that NADPH oxidase activity and Rac1 GTP activity are indispensable for the nongenomic actions of MRs and that Rac1 GTP activation induces ERK1/2 phosphorylation in the brain.

  4. Comment and response document for the final remedial action plan site design for stabilization of the Inactive Uranium Mill Tailings Sites at Slick Rock, Colorado

    SciTech Connect

    1995-09-01

    This document consists of comments and responses; the reviewers are the U.S. Nuclear Regulatory Commission (NRC), Colorado Dept. of Public Health and Environment, and the remedial action contractor (RAC).

  5. Hospital industry pushes back against the RACs.

    PubMed

    2013-01-01

    Groups ranging from the American Hospital Association to the U.S. Congress have taken up the issues posed by the Recovery Audit Contractors and other Medicare and Medicaid auditors. The high percentage of denials overturned upon appeal and large number of records requests are getting attention. Hospitals may get relief, but it's not likely to be immediate so they should continue preparing for the audits. Meanwhile, in addition to the Recovery Audit Contractors (RACs), hospitals are facing scrutiny from the Zoned Program Integrity Contractors (ZPICs), Medicare Prepayment Reviews, and Medicare Administrative Contractor (MAC) on-site audits. PMID:23339269

  6. 75 FR 54846 - Hood/Willamette Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-09

    ...; ] DEPARTMENT OF AGRICULTURE Forest Service Hood/Willamette Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Action of meeting. SUMMARY: The Hood/Willamette Resource Advisory Committee (RAC... FURTHER INFORMATION CONTACT: For more information regarding this meeting, contact Connie Athman; Mt....

  7. 75 FR 21220 - Hood/Willamette Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ... Forest Service Hood/Willamette Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Action of meeting. SUMMARY: The Hood/Willamette Resource Advisory Committee (RAC) will meet on Tuesday... meeting, contact Connie Athman; Mt. Hood National Forest; 16400 Champion Way; Sandy, Oregon 97055;...

  8. Rho/RacGAPs

    PubMed Central

    Csépányi-Kömi, Roland; Lévay, Magdolna; Ligeti, Erzsébet

    2012-01-01

    Regulatory proteins such as guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) determine the activity of small GTPases. In the Rho/Rac family, the number of GEFs and GAPs largely exceeds the number of small GTPases, raising the question of specific or overlapping functions. In our recent study we investigated the first time ARHGAP25 at the protein level, determined its activity as RacGAP and showed its involvement in phagocytosis. With the discovery of ARHGAP25, the number of RacGAPs described in phagocytes is increased to six. We provide data that indicate the specific functions of selected Rho/RacGAPs and we show an example of differential regulation of a Rho/Rac family GAP by different kinases. We propose that the abundance of Rho/Rac family GAPs is an important element of the fine spatiotemporal regulation of diverse cellular functions. PMID:22751505

  9. 76 FR 36482 - Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors Regarding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... regulations implementing the affirmative action provisions of the Vietnam Era Veterans' Readjustment..., 2011, OFCCP published a proposed rule entitled ``Affirmative Action and Nondiscrimination Obligations... of Federal Contract Compliance Programs 41 CFR Parts 60-250 and 60-300 RIN 1250-AA00...

  10. 75 FR 18144 - Hood/Willamette Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-09

    ...; ] DEPARTMENT OF AGRICULTURE Hood/Willamette Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Hood/Willamette Resource Advisory Committee (RAC) will meet on... INFORMATION CONTACT: For more information regarding this meeting, contact Connie Athman; Mt. Hood...

  11. Non-prenylatable, cytosolic Rac1 alters neurite outgrowth while retaining the ability to be activated.

    PubMed

    Reddy, Jairus M; Samuel, Filsy G; McConnell, Jordan A; Reddy, Cristina P; Beck, Brian W; Hynds, DiAnna L

    2015-03-01

    Rac1 is an important regulator of axon extension, cell migration and actin reorganization. Like all Rho guanine triphosphatases (GTPases), Rac1 is targeted to the membrane by the addition of a geranylgeranyl moiety, an action thought to result in Rac1 guanosine triphosphate (GTP) binding. However, the role that Rac1 localization plays in its activation (GTP loading) and subsequent activation of effectors is not completely clear. To address this, we developed a non-prenylatable emerald green fluorescent protein (EmGFP)-Rac1 fusion protein (EmGFP-Rac1(C189A)) and assessed how expressing this construct affected neurite outgrowth, Rac1 localization and activation in neuroblastoma cells. Expression of EmGFP-Rac1(C189A) increased localization to the cytosol and induced cell clustering while increasing neurite initiation. EmGFP-Rac1(C189A) expression also increased Rac1 activation in the cytosol, compared to cells expressing wild-type Rac1 (EmGFP-Rac1). These results suggest that activation of Rac1 may not require plasma membrane localization, potentially leading to differential activation of cytosolic signaling pathways that alter cell morphology. Understanding the consequences of differential localization and activation of Rho GTPases, including Rac1, could lead to new therapeutic targets for treating neurological disorders. PMID:25479592

  12. The impact of RAC audits on US hospitals.

    PubMed

    Harrison, Jeffrey P; Barksdale, Rachel M

    2013-01-01

    The Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) authorized a three-year demonstration program using recovery audit contractors (RACs) to identify and correct improper payments in the Medicare Fee-For-Service program. More recently, Section 6411 of the Affordable Care Act (ACA) expanded the RAC program to include the Medicaid program. This shows the Cent ers for Medicare & Medicaid Services (CMS) believe RAC audits are a cost-effective method to ensure health care providers are paid correctly and thereby protect the Medicare Trust Fund. RAC audits are highly complex and require significant manpower to handle the large volume of requests received during a short period of time. Additionally, the RAC audit appeal process is complicated and requires a high level of technical expertise. The demonstration project found that RAC audits resulted in sizeable amounts of overpayments collected ("take-backs") from many providers. This research study assesses the potential impact of the RAC audit program on US acute care hospitals. Data obtained from CMS show that RAC overpayments collected for FY 2010 were $75.4 million, increased to $797.4 million in FY 2011, and increased to $986.2 million in the first six months of FY 2012. According to the American Hospital Association (AHA) RACTrac audit survey, the vast majority of these collections represent complex denials where hospitals are required to provide medical record documents in support of their billed claims. This study found that the RAC audit program collections are increasing significantly over time. As a result, these collections are having a significant negative impact on the profitability of US hospitals.

  13. The impact of RAC audits on US hospitals.

    PubMed

    Harrison, Jeffrey P; Barksdale, Rachel M

    2013-01-01

    The Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) authorized a three-year demonstration program using recovery audit contractors (RACs) to identify and correct improper payments in the Medicare Fee-For-Service program. More recently, Section 6411 of the Affordable Care Act (ACA) expanded the RAC program to include the Medicaid program. This shows the Cent ers for Medicare & Medicaid Services (CMS) believe RAC audits are a cost-effective method to ensure health care providers are paid correctly and thereby protect the Medicare Trust Fund. RAC audits are highly complex and require significant manpower to handle the large volume of requests received during a short period of time. Additionally, the RAC audit appeal process is complicated and requires a high level of technical expertise. The demonstration project found that RAC audits resulted in sizeable amounts of overpayments collected ("take-backs") from many providers. This research study assesses the potential impact of the RAC audit program on US acute care hospitals. Data obtained from CMS show that RAC overpayments collected for FY 2010 were $75.4 million, increased to $797.4 million in FY 2011, and increased to $986.2 million in the first six months of FY 2012. According to the American Hospital Association (AHA) RACTrac audit survey, the vast majority of these collections represent complex denials where hospitals are required to provide medical record documents in support of their billed claims. This study found that the RAC audit program collections are increasing significantly over time. As a result, these collections are having a significant negative impact on the profitability of US hospitals. PMID:24003757

  14. Rac GTPases in Human Diseases

    PubMed Central

    Pai, Sung-Yun; Kim, Chaekyun; Williams, David A.

    2010-01-01

    Rho GTPases are members of the Ras superfamily of GTPases that regulate a wide variety of cellular functions. While Rho GTPase pathways have been implicated in various pathological conditions in humans, to date coding mutations in only the hematopoietic specific GTPase, RAC2, have been found to cause a human disease, a severe phagocytic immunodeficiency characterized by life-threatening infections in infancy. Interestingly, the phenotype was predicted by a mouse knock-out of RAC2 and resembles leukocyte adhesion deficiency (LAD). Here we review Rho GTPases with a specific focus on Rac GTPases. In particular, we discuss a new understanding of the unique and overlapping roles of Rac2 in blood cells that has developed since the generation of mice deficient in Rac1, Rac2 and Rac3 proteins. We propose that Rac2 mutations leading to disease be termed LAD type IV. PMID:21178276

  15. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Rifle, Colorado

    SciTech Connect

    Not Available

    1992-02-01

    This appendix assesses the present conditions and data gathered about the two inactive uranium mill tailings sites near Rifle, Colorado, and the designated disposal site six miles north of Rifle in the area of Estes Gulch. It consolidates available engineering, radiological, geotechnical, hydrological, meteorological, and other information pertinent to the design of the Remedial Action Plan (RAP). The data characterize conditions at the mill, tailings, and disposal site so that the Remedial Action Contractor (RAC) may complete final designs for the remedial actions.

  16. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Rifle, Colorado. Volume 2, Appendices D and E: Final report

    SciTech Connect

    Not Available

    1992-02-01

    This appendix assesses the present conditions and data gathered about the two inactive uranium mill tailings sites near Rifle, Colorado, and the designated disposal site six miles north of Rifle in the area of Estes Gulch. It consolidates available engineering, radiological, geotechnical, hydrological, meteorological, and other information pertinent to the design of the Remedial Action Plan (RAP). The data characterize conditions at the mill, tailings, and disposal site so that the Remedial Action Contractor (RAC) may complete final designs for the remedial actions.

  17. Provider experiences with RAC appeals point to opportunities for program improvement.

    PubMed

    Jacobs, Robert; Scott, Bonnie; Flood, Elizabeth; Scott, Ellen

    2011-03-01

    Review by an administrative law judge (ALJ) constitutes the third level of appeal for healthcare providers seeking to overturn reverse recovery audit contractor (RAC) findings of overpayment of Medicare claims. An analysis of the results of RAC appeals submitted by 30 New York hospitals during the demonstration project has disclosed two deficiencies in the ALJ review process: inconsistent ALJ decision making and a lack of an appropriate feedback mechanism to correct erroneous overpayment determinations. The Centers for Medicare & Medicaid Services should take advantage of feedback from such studies as an impetus to reevaluate and streamline the RAC appeals process. PMID:21449307

  18. Uranium Mill Tailings Remedial Action Project Safety Advancement Field Effort (SAFE) Program

    SciTech Connect

    Not Available

    1994-02-01

    In 1992, the Uranium Mill Tailings Remedial Action (UMTRA) Project experienced several health and safety related incidents at active remediation project sites. As a result, the U.S. Department of Energy (DOE) directed the Technical Assistance Contractor (TAC) to establish a program increasing the DOE`s overall presence at operational remediation sites to identify and minimize risks in operations to the fullest extent possible (Attachments A and B). In response, the TAC, in cooperation with the DOE and the Remedial Action Contractor (RAC), developed the Safety Advancement Field Effort (SAFE) Program.

  19. Economic impact study of the Uranium Mill Tailings Remedial Action project in Colorado: Colorado state fiscal year 1995

    SciTech Connect

    1995-12-01

    This Colorado economic impact study summarizes employment and economic benefits to the state from activities associated with the Uranium Mill Tailings Remedial Action (UMTRA) Project during Colorado state fiscal year (FY) 1995 (1 July 1994 through 30 June 1995). To capture employment information, a questionnaire was distributed to subcontractor employees at the active UMTRA Project sites of Grand Junction, Gunnison, Maybell, Naturita, Rifle, and Slick Rock, Colorado. Economic data were requested from the Remedial Action Contractor (RAC), the Technical Assistance Contractor (TAC) and the US Department of Energy (DOE). The most significant benefits associated with the UMTRA Project in Colorado are summarized.

  20. 77 FR 13153 - Information Collection; NASA Contractor Financial Management Reports

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-05

    ... SPACE ADMINISTRATION Information Collection; NASA Contractor Financial Management Reports AGENCY: National Aeronautics and Space Administration (NASA). ACTION: Notice of information collection. SUMMARY... . SUPPLEMENTARY INFORMATION: I. Abstract The NASA Contractor Financial Management Reporting System is the...

  1. Rho/RacGAPs: embarras de richesse?

    PubMed

    Csépányi-Kömi, Roland; Lévay, Magdolna; Ligeti, Erzsébet

    2012-01-01

    Regulatory proteins such as guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) determine the activity of small GTPases. In the Rho/Rac family, the number of GEFs and GAPs largely exceeds the number of small GTPases, raising the question of specific or overlapping functions. In our recent study we investigated the first time ARHGAP25 at the protein level, determined its activity as RacGAP and showed its involvement in phagocytosis. With the discovery of ARHGAP25, the number of RacGAPs described in phagocytes is increased to six. We provide data that indicate the specific functions of selected Rho/RacGAPs and we show an example of differential regulation of a Rho/Rac family GAP by different kinases. We propose that the abundance of Rho/Rac family GAPs is an important element of the fine spatiotemporal regulation of diverse cellular functions.

  2. Remedial action plan and site conceptual design for stabilization of the inactive uranium mill tailings sites at Rifle, Colorado. Appendix D, Final report

    SciTech Connect

    1992-02-01

    This appendix assesses the present conditions and data gathered about the two designated inactive uranium mill tailings sites near Rifle, Colorado, and the proposed disposal site six miles north of Rifle in the area of Estes Gulch. It consolidates available engineering, radiological, geotechnical, hydrological, meteorological, and other information pertinent to the design of the Remedial Action Plan (RAP). The data characterize conditions at the mill, tailings, and disposal site so that the Remedial Action Contractor (RAC) may complete final designs for the remedial actions.

  3. Rac1-Rab11-FIP3 regulatory hub coordinates vesicle traffic with actin remodeling and T-cell activation.

    PubMed

    Bouchet, Jérôme; Del Río-Iñiguez, Iratxe; Lasserre, Rémi; Agüera-Gonzalez, Sonia; Cuche, Céline; Danckaert, Anne; McCaffrey, Mary W; Di Bartolo, Vincenzo; Alcover, Andrés

    2016-06-01

    The immunological synapse generation and function is the result of a T-cell polarization process that depends on the orchestrated action of the actin and microtubule cytoskeleton and of intracellular vesicle traffic. However, how these events are coordinated is ill defined. Since Rab and Rho families of GTPases control intracellular vesicle traffic and cytoskeleton reorganization, respectively, we investigated their possible interplay. We show here that a significant fraction of Rac1 is associated with Rab11-positive recycling endosomes. Moreover, the Rab11 effector FIP3 controls Rac1 intracellular localization and Rac1 targeting to the immunological synapse. FIP3 regulates, in a Rac1-dependent manner, key morphological events, like T-cell spreading and synapse symmetry. Finally, Rab11-/FIP3-mediated regulation is necessary for T-cell activation leading to cytokine production. Therefore, Rac1 endosomal traffic is key to regulate T-cell activation.

  4. Radiological surveillance of Remedial Action activities at the processing site, Ambrosia Lake, New Mexico, April 12--16, 1993. Final report

    SciTech Connect

    1993-04-01

    The Uranium Mill Tailings Remedial Action (UMTRA) Project`s Technical Assistance Contractor (TAC) performed a radiological surveillance of the Remedial Action Contractor (RAC), MK-Ferguson and CWM Federal Environmental Services, Inc., at the processing site in Ambrosia Lake, New Mexico. The requirements and attributes examined during the audit were developed from reviewing working-level procedures developed by the RAC. Objective evidence, comments, and observations were verified based on investigating procedures, documentation, records located at the site, personal interviews, and tours of the site. No findings were identified during this audit. Ten site-specific observations, three good practice observations, and five programmatic observations are presented in this report. The overall conclusion from the surveillance is that the radiological aspects of the Ambrosia Lake, New Mexico, remedial action program are performed adequately. The results of the good practice observations indicate that the site health physics (HP) staff is taking the initiative to address and resolve potential issues, and implement suggestions useful to the UMTRA Project. However, potential exists for improving designated storage areas for general items, and the RAC Project Office should consider resolving site-specific and procedural inconsistencies.

  5. 75 FR 81278 - Medicare Program: Solicitation of Comments Regarding Development of a Recovery Audit Contractor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ... rules for the MA program (69 FR 46866) and prescription drug benefit program (69 FR 46632). The final regulations implementing both programs, published on January 28, 2005 (70 FR 4588 and 70 FR 4194, respectively..., the RAC contractor would come to an agreement with interested MA organizations (MAO) to conduct...

  6. Mitigation action plan for remedial action at the Uranium Mill Tailing Sites and Disposal Site, Rifle, Colorado

    SciTech Connect

    Not Available

    1992-07-01

    The Estes Gulch disposal site is approximately 10 kilometers (6 miles) north of the town of Rifle, off State Highway 13 on Federal land administered by the Bureau of Land Management. The Department of Energy (DOE) will transport the residual radioactive materials (RRM) by truck to the Estes Gulch disposal site via State Highway 13 and place it in a partially below-grade disposal cell. The RRM will be covered by an earthen radon barrier, frost protection layers, and a rock erosion protection layer. A toe ditch and other features will also be constructed to control erosion at the disposal site. After removal of the RRM and disposal at the Estes Gulch site, the disturbed areas at all three sites will be backfilled with clean soils, contoured to facilitate surface drainage, and revegetated. Wetlands areas destroyed at the former Rifle processing sites will be compensated for by the incorporation of now wetlands into the revegetation plan at the New Rifle site. The UMTRA Project Office, supported by the Remedial Action Contractor (RAC) and the Technical Assistance Contractor (TAC), oversees the implementation of the MAP. The RAC executes mitigation measures in the field. The TAC provides monitoring of the mitigation actions in cases where mitigation measures are associated with design features. Site closeout and inspection compliance will be documented in the site completion report.

  7. Rac1 deletion causes thymic atrophy.

    PubMed

    Hunziker, Lukas; Benitah, Salvador Aznar; Aznar Benitah, Salvador; Braun, Kristin M; Jensen, Kim; McNulty, Katrina; Butler, Colin; Potton, Elspeth; Nye, Emma; Boyd, Richard; Laurent, Geoff; Glogauer, Michael; Wright, Nick A; Watt, Fiona M; Janes, Sam M

    2011-04-29

    The thymic stroma supports T lymphocyte development and consists of an epithelium maintained by thymic epithelial progenitors. The molecular pathways that govern epithelial homeostasis are poorly understood. Here we demonstrate that deletion of Rac1 in Keratin 5/Keratin 14 expressing embryonic and adult thymic epithelial cells leads to loss of the thymic epithelial compartment. Rac1 deletion led to an increase in c-Myc expression and a generalized increase in apoptosis associated with a decrease in thymic epithelial proliferation. Our results suggest Rac1 maintains the epithelial population, and equilibrium between Rac1 and c-Myc may control proliferation, apoptosis and maturation of the thymic epithelial compartment. Understanding thymic epithelial maintenance is a step toward the dual goals of in vitro thymic epithelial cell culture and T cell differentiation, and the clinical repair of thymic damage from graft-versus-host-disease, chemotherapy or irradiation.

  8. Contractor safety training reciprocity

    SciTech Connect

    Melancon, R.

    1996-08-01

    In June, 1995, the National Petroleum Refiners Association (NPRA) adhoc committee on Contractor Safety Training, turned over the task of developing reciprocity agreements with all Contractor Safety Training Councils to the Executive Directors of each of the Council`s. The Council representatives were to develop these agreements based on the NPRA adhoc committee training objectives that were developed jointly by representatives of the petroleum industry, chemical industry, contractors and the Council`s.

  9. Differential Rac1 signalling by guanine nucleotide exchange factors implicates FLII in regulating Rac1-driven cell migration

    PubMed Central

    Marei, Hadir; Carpy, Alejandro; Woroniuk, Anna; Vennin, Claire; White, Gavin; Timpson, Paul; Macek, Boris; Malliri, Angeliki

    2016-01-01

    The small GTPase Rac1 has been implicated in the formation and dissemination of tumours. Upon activation by guanine nucleotide exchange factors (GEFs), Rac1 associates with a variety of proteins in the cell thereby regulating various functions, including cell migration. However, activation of Rac1 can lead to opposing migratory phenotypes raising the possibility of exacerbating tumour progression when targeting Rac1 in a clinical setting. This calls for the identification of factors that influence Rac1-driven cell motility. Here we show that Tiam1 and P-Rex1, two Rac GEFs, promote Rac1 anti- and pro-migratory signalling cascades, respectively, through regulating the Rac1 interactome. In particular, we demonstrate that P-Rex1 stimulates migration through enhancing the interaction between Rac1 and the actin-remodelling protein flightless-1 homologue, to modulate cell contraction in a RhoA-ROCK-independent manner. PMID:26887924

  10. Contractor or Employee? Reporting Independent Contractor Payments.

    ERIC Educational Resources Information Center

    Dickson, Roger J.

    1993-01-01

    Congress has approved new penalties to be assessed against employers who improperly file required tax forms. Includes a 20-factor control test developed by the Internal Revenue Service to help determine whether a worker is an employee or an independent contractor. School business officials should review payment procedures to ensure that proper tax…

  11. Rac1 mediates intestinal epithelial cell apoptosis via JNK.

    PubMed

    Jin, Shi; Ray, Ramesh M; Johnson, Leonard R

    2006-12-01

    Apoptosis plays a key role in the maintenance of a constant cell number and a low incidence of cancer in the mucosa of the intestine. Although the small GTPase Rac1 has been established as an important regulator of migration of intestinal epithelial cells, whether Rac1 is also involved in apoptosis is unclear. The present study tested the hypothesis that Rac1 mediates TNF-alpha-induced apoptosis in IEC-6 cells. Rac1 is activated during TNF-alpha-induced apoptosis as judged by the level of GTP-Rac1, the level of microsomal membrane-associated Rac1, and lamellipodia formation. Although expression of constitutively active Rac1 does not increase apoptosis in the basal condition, inhibition of Rac1 either by NSC-23766 (Rac1 inhibitor) or expression of dominant negative Rac1 protects cells from TNF-alpha-induced apoptosis by inhibiting caspase-3, -8, and -9 activities. Inhibition of Rac1 before the administration of apoptotic stimuli significantly prevents TNF-alpha-induced activation of JNK1/2, the key proapoptotic regulator in IEC-6 cells. Inhibition of Rac1 does not modulate TNF-alpha-induced ERK1/2 and Akt activation. Inhibition of ERK1/2 and Akt activity by U-0126 and LY-294002, respectively, increased TNF-alpha-induced apoptosis. However, inhibition of Rac1 significantly decreased apoptosis in the presence of ERK1/2 and Akt inhibitors, similar to the effect observed with NSC-23766 alone in response to TNF-alpha. Thus, Rac1 inhibition protects cells independently of ERK1/2 and Akt activation during TNF-alpha-induced apoptosis. Although p38 MAPK is activated in response to TNF-alpha, inhibition of p38 MAPK did not decrease apoptosis. Rac1 inhibition did not alter p38 MAPK activity. Thus, these results indicate that Rac1 mediates apoptosis via JNK and plays a key role in proapoptotic pathways in intestinal epithelial cells.

  12. Contingency contractor optimization.

    SciTech Connect

    Gearhart, Jared Lee; Adair, Kristin Lynn; Jones, Katherine A.; Bandlow, Alisa; Durfee, Justin David.; Jones, Dean A.; Martin, Nathaniel; Detry, Richard Joseph; Nanco, Alan Stewart; Nozick, Linda Karen

    2013-10-01

    The goal of Phase 3 the OSD ATL Contingency Contractor Optimization (CCO) project is to create an engineering prototype of a tool for the contingency contractor element of total force planning during the Support for Strategic Analysis (SSA). An optimization model was developed to determine the optimal mix of military, Department of Defense (DoD) civilians, and contractors that accomplishes a set of user defined mission requirements at the lowest possible cost while honoring resource limitations and manpower use rules. An additional feature allows the model to understand the variability of the Total Force Mix when there is uncertainty in mission requirements.

  13. Contingency contractor optimization.

    SciTech Connect

    Gearhart, Jared Lee; Adair, Kristin Lynn; Jones, Katherine A.; Bandlow, Alisa; Detry, Richard Joseph; Durfee, Justin David.; Jones, Dean A.; Martin, Nathaniel; Nanco, Alan Stewart; Nozick, Linda Karen

    2013-06-01

    The goal of Phase 3 the OSD ATL Contingency Contractor Optimization (CCO) project is to create an engineering prototype of a tool for the contingency contractor element of total force planning during the Support for Strategic Analysis (SSA). An optimization model was developed to determine the optimal mix of military, Department of Defense (DoD) civilians, and contractors that accomplishes a set of user defined mission requirements at the lowest possible cost while honoring resource limitations and manpower use rules. An additional feature allows the model to understand the variability of the Total Force Mix when there is uncertainty in mission requirements.

  14. Coevolution of RAC Small GTPases and their Regulators GEF Proteins

    PubMed Central

    Jiménez-Sánchez, Alejandro

    2016-01-01

    RAC proteins are small GTPases involved in important cellular processes in eukaryotes, and their deregulation may contribute to cancer. Activation of RAC proteins is regulated by DOCK and DBL protein families of guanine nucleotide exchange factors (GEFs). Although DOCK and DBL proteins act as GEFs on RAC proteins, DOCK and DBL family members are evolutionarily unrelated. To understand how DBL and DOCK families perform the same function on RAC proteins despite their unrelated primary structure, phylogenetic analyses of the RAC, DBL, and DOCK families were implemented, and interaction patterns that may suggest a coevolutionary process were searched. Interestingly, while RAC and DOCK proteins are very well conserved in humans and among eukaryotes, DBL proteins are highly divergent. Moreover, correlation analyses of the phylogenetic distances of RAC and GEF proteins and covariation analyses between residues in the interacting domains showed significant coevolution rates for both RAC–DOCK and RAC–DBL interactions. PMID:27226705

  15. 40 CFR 35.6600 - Contractor claims.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... STATE AND LOCAL ASSISTANCE Cooperative Agreements and Superfund State Contracts for Superfund Response Actions Procurement Requirements Under A Cooperative Agreement § 35.6600 Contractor claims. (a) General... against the recipient under a contract, provided: (1) The claim arises from work within the scope of...

  16. Physiological Function of Rac Prophage During Biofilm Formation and Regulation of Rac Excision in Escherichia coli K-12.

    PubMed

    Liu, Xiaoxiao; Li, Yangmei; Guo, Yunxue; Zeng, Zhenshun; Li, Baiyuan; Wood, Thomas K; Cai, Xingsheng; Wang, Xiaoxue

    2015-11-04

    Rac or rac-like prophage harbors many genes with important physiological functions, while it remains excision-proficient in several bacterial strains including Escherichia coli, Salmonella spp. and Shigella spp. Here, we found that rac excision is induced during biofilm formation, and the isogenic stain without rac is more motile and forms more biofilms in nutrient-rich medium at early stages in E. coli K-12. Additionally, the presence of rac genes increases cell lysis during biofilm development. In most E. coli strains, rac is integrated into the ttcA gene which encodes a tRNA-thioltransferase. Rac excision in E. coli K-12 leads to a functional change of TtcA, which results in reduced fitness in the presence of carbenicillin. Additionally, we demonstrate that YdaQ (renamed as XisR) is the excisionase of rac in E. coli K-12, and that rac excision is induced by the stationary sigma factor RpoS through inducing xisR expression. Taken together, our results reveal that upon rac integration, not only are new genes introduced into the host, but also there is a functional change in a host enzyme. Hence, rac excision is tightly regulated by host factors to control its stability in the host genome under different stress conditions.

  17. Serine-71 phosphorylation of Rac1 modulates downstream signaling.

    PubMed

    Schwarz, Janett; Proff, Julia; Hävemeier, Anika; Ladwein, Markus; Rottner, Klemens; Barlag, Britta; Pich, Andreas; Tatge, Helma; Just, Ingo; Gerhard, Ralf

    2012-01-01

    The Rho GTPases Rac1 and Cdc42 regulate a variety of cellular functions by signaling to different signal pathways. It is believed that the presence of a specific effector at the location of GTPase activation determines the route of downstream signaling. We previously reported about EGF-induced Ser-71 phosphorylation of Rac1/Cdc42. By using the phosphomimetic S71E-mutants of Rac1 and Cdc42 we investigated the impact of Ser-71 phosphorylation on binding to selected effector proteins. Binding of the constitutively active (Q61L) variants of Rac1 and Cdc42 to their specific interaction partners Sra-1 and N-WASP, respectively, as well as to their common effector protein PAK was abrogated when Ser-71 was exchanged to glutamate as phosphomimetic substitution. Interaction with their common effector proteins IQGAP1/2/3 or MRCK alpha was, however, hardly affected. This ambivalent behaviour was obvious in functional assays. In contrast to Rac1 Q61L, phosphomimetic Rac1 Q61L/S71E was not able to induce increased membrane ruffling. Instead, Rac1 Q61L/S71E allowed filopodia formation, which is in accordance with abrogation of the dominant Sra-1/Wave signalling pathway. In addition, in contrast to Rac1 transfected cells Rac1 S71E failed to activate PAK1/2. On the other hand, Rac1 Q61L/S71E was as effective in activation of NF-kappaB as Rac1 Q61L, illustrating positive signal transduction of phosphorylated Rac1. Together, these data suggest that phosphorylation of Rac1 and Cdc42 at serine-71 represents a reversible mechanism to shift specificity of GTPase/effector coupling, and to preferentially address selected downstream pathways. PMID:22970203

  18. 77 FR 7579 - Debarment, Suspension, and Ineligibility of Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-13

    .... ACTION: Policy statement. SUMMARY: On September 30, 2011, the Government Accountability Office (GAO..., and ineligibility of government contractors. Neither comment suggested any changes to GAO's policy...: Questions concerning this policy can be addressed to Government Accountability Office, Office of the...

  19. RAC: Repository of Antibiotic resistance Cassettes

    PubMed Central

    Tsafnat, Guy; Copty, Joseph; Partridge, Sally R.

    2011-01-01

    Antibiotic resistance in bacteria is often due to acquisition of resistance genes associated with different mobile genetic elements. In Gram-negative bacteria, many resistance genes are found as part of small mobile genetic elements called gene cassettes, generally found integrated into larger elements called integrons. Integrons carrying antibiotic resistance gene cassettes are often associated with mobile elements and here are designated ‘mobile resistance integrons’ (MRIs). More than one cassette can be inserted in the same integron to create arrays that contribute to the spread of multi-resistance. In many sequences in databases such as GenBank, only the genes within cassettes, rather than whole cassettes, are annotated and the same gene/cassette may be given different names in different entries, hampering analysis. We have developed the Repository of Antibiotic resistance Cassettes (RAC) website to provide an archive of gene cassettes that includes alternative gene names from multiple nomenclature systems and allows the community to contribute new cassettes. RAC also offers an additional function that allows users to submit sequences containing cassettes or arrays for annotation using the automatic annotation system Attacca. Attacca recognizes features (gene cassettes, integron regions) and identifies cassette arrays as patterns of features and can also distinguish minor cassette variants that may encode different resistance phenotypes (aacA4 cassettes and bla cassettes-encoding β-lactamases). Gaps in annotations are manually reviewed and those found to correspond to novel cassettes are assigned unique names. While there are other websites dedicated to integrons or antibiotic resistance genes, none includes a complete list of antibiotic resistance gene cassettes in MRI or offers consistent annotation and appropriate naming of all of these cassettes in submitted sequences. RAC thus provides a unique resource for researchers, which should reduce confusion

  20. Strategies for responding to RAC requests electronically.

    PubMed

    Schramm, Michael

    2012-04-01

    Providers that would like to respond to complex RAC reviews electronically should consider three strategies: Invest in an EHR software package or a high-powered scanner that can quickly scan large amounts of paper. Implement an audit software platform that will allow providers to manage the entire audit process in one place. Use a CONNECT-compatible gateway capable of accessing the Nationwide Health Information Network (the network on which the electronic submission of medical documentation program runs).

  1. 77 FR 41447 - Notice of Utah's Resource Advisory Council (RAC)/Recreation Resource Advisory Council (RRAC) Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... Bureau of Land Management Notice of Utah's Resource Advisory Council (RAC)/Recreation Resource Advisory Council (RRAC) Meeting AGENCY: Bureau of Land Management, Interior. ACTION: Notice. SUMMARY: In accordance with the Federal Land Policy and Management Act and the Federal Advisory Committee Act of 1972,...

  2. CD28-dependent Rac1 activation is the molecular target of azathioprine in primary human CD4+ T lymphocytes

    PubMed Central

    Tiede, Imke; Fritz, Gerhard; Strand, Susanne; Poppe, Daniela; Dvorsky, Radovan; Strand, Dennis; Lehr, Hans Anton; Wirtz, Stefan; Becker, Christoph; Atreya, Raja; Mudter, Jonas; Hildner, Kai; Bartsch, Brigitte; Holtmann, Martin; Blumberg, Richard; Walczak, Henning; Iven, Heiko; Galle, Peter R.; Ahmadian, Mohammad Reza; Neurath, Markus F.

    2003-01-01

    Azathioprine and its metabolite 6-mercaptopurine (6-MP) are immunosuppressive drugs that are used in organ transplantation and autoimmune and chronic inflammatory diseases such as Crohn disease. However, their molecular mechanism of action is unknown. In the present study, we have identified a unique and unexpected role for azathioprine and its metabolites in the control of T cell apoptosis by modulation of Rac1 activation upon CD28 costimulation. We found that azathioprine and its metabolites induced apoptosis of T cells from patients with Crohn disease and control patients. Apoptosis induction required costimulation with CD28 and was mediated by specific blockade of Rac1 activation through binding of azathioprine-generated 6-thioguanine triphosphate (6-Thio-GTP) to Rac1 instead of GTP. The activation of Rac1 target genes such as mitogen-activated protein kinase kinase (MEK), NF-κB, and bcl-xL was suppressed by azathioprine, leading to a mitochondrial pathway of apoptosis. Azathioprine thus converts a costimulatory signal into an apoptotic signal by modulating Rac1 activity. These findings explain the immunosuppressive effects of azathioprine and suggest that 6-Thio-GTP derivates may be useful as potent immunosuppressive agents in autoimmune diseases and organ transplantation. PMID:12697733

  3. 76 FR 2883 - Humboldt Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-18

    ... Forest Office, 1330 Bayshore Way, Eureka, CA 95501. FOR FURTHER INFORMATION CONTACT: Adam Dellinger... Meeting. SUMMARY: The Humboldt Resource Advisory Committee (RAC) will meet in Eureka, California....

  4. 75 FR 69620 - Humboldt Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... Forest Office, 1330 Bayshore Way, Eureka, CA 95501. FOR FURTHER INFORMATION CONTACT: Adam Dellinger... meeting. SUMMARY: The Humboldt Resource Advisory Committee (RAC) will meet in Eureka, California....

  5. 75 FR 43140 - Humboldt Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-23

    ... Forest Office, 1330 Bayshore Way, Eureka, CA 95501. FOR FURTHER INFORMATION CONTACT: Julie Ranieri... meeting. SUMMARY: The Humboldt Resource Advisory Committee (RAC) will meet in Eureka, California....

  6. 75 FR 54297 - Humboldt Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-07

    ... Forest Office, 1330 Bayshore Way, Eureka, CA 95501. FOR FURTHER INFORMATION CONTACT: Julie Ranieri... meeting. SUMMARY: The Humboldt Resource Advisory Committee (RAC) will meet in Eureka, California....

  7. Hydrogen Contractors Meeting

    SciTech Connect

    Fitzsimmons, Tim

    2006-05-16

    This volume highlights the scientific content of the 2006 Hydrogen Contractors Meeting sponsored by the Division of Materials Sciences and Engineering (DMS&E) on behalf of the Office of Basic Energy Sciences (BES) of the U. S. Department of Energy (DOE). Hydrogen Contractors Meeting held from May 16-19, 2006 at the Crystal Gateway Marriott Hotel Arlington, Virginia. This meeting is the second in a series of research theme-based Contractors Meetings sponsored by DMS&E held in conjunction with our counterparts in the Office of Energy Efficiency and Renewable Energy (EERE) and the first with the Hydrogen, Fuel Cells and Infrastructure Technologies Program. The focus of this year’s meeting is BES funded fundamental research underpinning advancement of hydrogen storage. The major goals of these research efforts are the development of a fundamental scientific base in terms of new concepts, theories and computational tools; new characterization capabilities; and new materials that could be used or mimicked in advancing capabilities for hydrogen storage.

  8. The Calponin Family Member CHDP-1 Interacts with Rac/CED-10 to Promote Cell Protrusions

    PubMed Central

    Zhang, Jingyan; Liu, Jia-Jia; Wang, Yingchun; Ding, Mei

    2016-01-01

    Eukaryotic cells extend a variety of surface protrusions to direct cell motility. Formation of protrusions is mediated by coordinated actions between the plasma membrane and the underlying actin cytoskeleton. Here, we found that the single calponin homology (CH) domain-containing protein CHDP-1 induces the formation of cell protrusions in C. elegans. CHDP-1 is anchored to the cortex through its amphipathic helix. CHDP-1 associates through its CH domain with the small GTPase Rac1/CED-10, which is a key regulator of the actin cytoskeleton. CHDP-1 preferentially binds to the GTP-bound active form of the CED-10 protein and preserves the membrane localization of GTP-CED-10. Hence, by coupling membrane expansion to Rac1-mediated actin dynamics, CHDP-1 promotes the formation of cellular protrusions in vivo. PMID:27415421

  9. The Calponin Family Member CHDP-1 Interacts with Rac/CED-10 to Promote Cell Protrusions.

    PubMed

    Guan, Liying; Ma, Xuehua; Zhang, Jingyan; Liu, Jia-Jia; Wang, Yingchun; Ding, Mei

    2016-07-01

    Eukaryotic cells extend a variety of surface protrusions to direct cell motility. Formation of protrusions is mediated by coordinated actions between the plasma membrane and the underlying actin cytoskeleton. Here, we found that the single calponin homology (CH) domain-containing protein CHDP-1 induces the formation of cell protrusions in C. elegans. CHDP-1 is anchored to the cortex through its amphipathic helix. CHDP-1 associates through its CH domain with the small GTPase Rac1/CED-10, which is a key regulator of the actin cytoskeleton. CHDP-1 preferentially binds to the GTP-bound active form of the CED-10 protein and preserves the membrane localization of GTP-CED-10. Hence, by coupling membrane expansion to Rac1-mediated actin dynamics, CHDP-1 promotes the formation of cellular protrusions in vivo. PMID:27415421

  10. Characterisation of the Rac/PAK pathway in Amoeba proteus.

    PubMed

    Kłopocka, W; Moraczewska, J; Redowicz, M J

    2005-04-01

    Molecular mechanisms underlying the unique locomotion of the highly motile Amoeba proteus still remain poorly understood. Recently, we have shown that blocking the endogenous amoebal Rac-like protein(s) leads to distinct and irreversible changes in the appearance of these large migrating cells as well as to a significant inhibition of their locomotion. To elucidate the mechanism of the Rac pathway in Amoeba proteus, we tested the effects of blocking the endogenous myosin I heavy chain kinase (MIHCK), one of the Rac effectors in Acanthamoeba castellanii and Dictyostelium discoideum, with anti-MIHCK antibodies in migrating amoebae, as well as the effect of inhibiting Rac and MIHCK on the actin polymerisation process. Antibodies against A. castellanii MIHCK detected an A. proteus protein with a molecular mass (ca. 95 kDa) similar to the A. castellanii kinase. The cellular distribution of MIHCK in A. proteus was very similar to those of Rac-like protein in amoebae and MIHCK in A. castellanii. Amoebae microinjected with anti-MIHCK antibodies moved slower and protruded fewer wide pseudopodia (5-6) than the control cells (9-10), resembling to some extent the phenotype of cells microinjected with anti-Rac antibodies. The in vitro studies indicate that the A. proteus Rac-like protein, but not the MIHCK isoform, is engaged in the regulation of the nucleation step of the actin polymerisation process. These observations suggest that MIHCK may be one of the effectors for Rac in these extremely large cells.

  11. Characterisation of the Rac/PAK pathway in Amoeba proteus.

    PubMed

    Kłopocka, W; Moraczewska, J; Redowicz, M J

    2005-04-01

    Molecular mechanisms underlying the unique locomotion of the highly motile Amoeba proteus still remain poorly understood. Recently, we have shown that blocking the endogenous amoebal Rac-like protein(s) leads to distinct and irreversible changes in the appearance of these large migrating cells as well as to a significant inhibition of their locomotion. To elucidate the mechanism of the Rac pathway in Amoeba proteus, we tested the effects of blocking the endogenous myosin I heavy chain kinase (MIHCK), one of the Rac effectors in Acanthamoeba castellanii and Dictyostelium discoideum, with anti-MIHCK antibodies in migrating amoebae, as well as the effect of inhibiting Rac and MIHCK on the actin polymerisation process. Antibodies against A. castellanii MIHCK detected an A. proteus protein with a molecular mass (ca. 95 kDa) similar to the A. castellanii kinase. The cellular distribution of MIHCK in A. proteus was very similar to those of Rac-like protein in amoebae and MIHCK in A. castellanii. Amoebae microinjected with anti-MIHCK antibodies moved slower and protruded fewer wide pseudopodia (5-6) than the control cells (9-10), resembling to some extent the phenotype of cells microinjected with anti-Rac antibodies. The in vitro studies indicate that the A. proteus Rac-like protein, but not the MIHCK isoform, is engaged in the regulation of the nucleation step of the actin polymerisation process. These observations suggest that MIHCK may be one of the effectors for Rac in these extremely large cells. PMID:15948264

  12. Roles of Rac1 and Rac3 GTPases during the development of cortical and hippocampal GABAergic interneurons.

    PubMed

    de Curtis, Ivan

    2014-01-01

    Rac GTPases are regulators of the cytoskeleton that play an important role in several aspects of neuronal and brain development. Two distinct Rac GTPases are expressed in the developing nervous system, the widely expressed Rac1 and the neural-specific Rac3 proteins. Recent experimental evidence supports a central role of these two Rac proteins in the development of inhibitory GABAergic interneurons, important modulatory elements of the brain circuitry. The combined inactivation of the genes for the two Rac proteins has profound effects on distinct aspects of interneuron development, and has highlighted a synergistic contribution of the two proteins to the postmitotic maturation of specific populations of cortical and hippocampal interneurons. Rac function is modulated by different types of regulators, and can influence the activity of specific effectors. Some of these proteins have been associated to the development and maturation of interneurons. Cortical interneuron dysfunction is implicated in several neurological and psychiatric diseases characterized by cognitive impairment. Therefore the description of the cellular processes regulated by the Rac GTPases, and the identification of the molecular networks underlying these processes during interneuron development is relevant to the understanding of the role of GABAergic interneurons in cognitive functions.

  13. Roles of Rac1 and Rac3 GTPases during the development of cortical and hippocampal GABAergic interneurons

    PubMed Central

    de Curtis, Ivan

    2014-01-01

    Rac GTPases are regulators of the cytoskeleton that play an important role in several aspects of neuronal and brain development. Two distinct Rac GTPases are expressed in the developing nervous system, the widely expressed Rac1 and the neural-specific Rac3 proteins. Recent experimental evidence supports a central role of these two Rac proteins in the development of inhibitory GABAergic interneurons, important modulatory elements of the brain circuitry. The combined inactivation of the genes for the two Rac proteins has profound effects on distinct aspects of interneuron development, and has highlighted a synergistic contribution of the two proteins to the postmitotic maturation of specific populations of cortical and hippocampal interneurons. Rac function is modulated by different types of regulators, and can influence the activity of specific effectors. Some of these proteins have been associated to the development and maturation of interneurons. Cortical interneuron dysfunction is implicated in several neurological and psychiatric diseases characterized by cognitive impairment. Therefore the description of the cellular processes regulated by the Rac GTPases, and the identification of the molecular networks underlying these processes during interneuron development is relevant to the understanding of the role of GABAergic interneurons in cognitive functions. PMID:25309333

  14. Government - contractor interaction

    NASA Technical Reports Server (NTRS)

    Thomas, D. M.

    1983-01-01

    The development of the Administrative Contracting Officer represents an advance in the Government system of contract management because it provides an individual with knowledge, time, and a specialized function to insure performance of Government contracts. However, the development has created a dichotomy between the award and the post-award function which increases the adversary relationship with Government contractors. This paper advocates that this adversary relationship can be decreased if PCOs and ACOs are provided with opportunities to serve in the assignments of the other.

  15. Rac1 Activation Caused by Membrane Translocation of a Guanine Nucleotide Exchange Factor in Akt2-Mediated Insulin Signaling in Mouse Skeletal Muscle

    PubMed Central

    Takenaka, Nobuyuki; Nihata, Yuma; Satoh, Takaya

    2016-01-01

    Insulin-stimulated glucose uptake in skeletal muscle is mediated by the glucose transporter GLUT4, which is translocated to the plasma membrane following insulin stimulation. Several lines of evidence suggested that the protein kinase Akt2 plays a key role in this insulin action. The small GTPase Rac1 has also been implicated as a regulator of insulin-stimulated GLUT4 translocation, acting downstream of Akt2. However, the mechanisms whereby Akt2 regulates Rac1 activity remain obscure. The guanine nucleotide exchange factor FLJ00068 has been identified as a direct regulator of Rac1 in Akt2-mediated signaling, but its characterization was performed mostly in cultured myoblasts. Here, we provide in vivo evidence that FLJ00068 indeed acts downstream of Akt2 as a Rac1 regulator by using mouse skeletal muscle. Small interfering RNA knockdown of FLJ00068 markedly diminished GLUT4 translocation to the sarcolemma following insulin administration or ectopic expression of a constitutively activated mutant of either phosphoinositide 3-kinase or Akt2. Additionally, insulin and these constitutively activated mutants caused the activation of Rac1 as shown by immunofluorescent microscopy using a polypeptide probe specific to activated Rac1 in isolated gastrocnemius muscle fibers and frozen sections of gastrocnemius muscle. This Rac1 activation was also abrogated by FLJ00068 knockdown. Furthermore, we observed translocation of FLJ00068 to the cell periphery following insulin stimulation in cultured myoblasts. Localization of FLJ00068 in the plasma membrane in insulin-stimulated, but not unstimulated, myoblasts and mouse gastrocnemius muscle was further affirmed by subcellular fractionation and subsequent immunoblotting. Collectively, these results strongly support a critical role of FLJ00068 in Akt2-mediated Rac1 activation in mouse skeletal muscle insulin signaling. PMID:27163697

  16. Action!

    ERIC Educational Resources Information Center

    Senese, Joseph

    1998-01-01

    A small group of teachers at one Illinois high school is helping to effect and promote change. Through the Action Research Laboratory (ARL), teams of teachers conduct collaborative action research to improve classroom practices. Data from the first two years of the ARL indicate that teachers are eager to participate in, and have thrived in, their…

  17. Rac1 activity regulates proliferation of aggressive metastatic melanoma

    SciTech Connect

    Bauer, Natalie N. Chen Yihwen; Samant, Rajeev S.; Shevde, Lalita A.; Fodstad, Oystein

    2007-11-01

    Molecular mechanisms underlying the different capacity of two in vivo selected human melanoma cell variants to form experimental metastases were studied. The doubling times of the FEMX-I and FEMX-V cell sublines in vitro were 15 and 25 h, respectively. The invasive capacity of FEMX-I cells was 8-fold higher than FEMX-V cells, and the time to form approximately 10 mm s.c. tumors in nude mice was 21 versus 35 days. FEMX-I displayed a spindle-like formation in vitro, whereas FEMX-V cells had a rounded shape. Hence, we examined known determinants of cell shape and proliferation, the small GTPases. The four studied showed equal expression in both cell types, but Rac1 activity was significantly decreased in FEMX-V cells. Rac1 stimulates NF{kappa}B, and we found that endogenous NF{kappa}B activity of FEMX-V cells was 2% of that of FEMX-I cells. Inhibition of Rac1 resulted in blocked NF{kappa}B activity. Specific inhibition of either Rac1 or NF{kappa}B significantly reduced proliferation and invasion of FEMX-I cells, the more pronounced effects observed with Rac1 inhibition. These data indicate that Rac1 activity in FEMX cells regulates cell proliferation and invasion, in part via its effect on NF{kappa}B, signifying Rac1 as a key molecule in melanoma progression and metastasis.

  18. Optogenetics: optical control of a photoactivatable Rac in living cells.

    PubMed

    Yin, Taofei; Wu, Yi I

    2015-01-01

    Recent developments in optogenetics have extended optical control of signaling to intracellular proteins, including Rac, a small G protein in the Rho family. A blue light-sensing LOV (light, oxygen, or voltage) domain derived from Avena sativa (oat) phototropin was fused to the N-terminus of a constitutively active mutant of Rac, via an α-helix (Jα) that is conserved among plant phototropins. The fused LOV domain occluded binding of downstream effectors to Rac in the dark. Exposure to blue light caused a conformational change of the LOV domain and unwinding of the Jα helix, relieving steric inhibition. The LOV domain incorporates a flavin as the photon-absorbing cofactor and can be activated by light in a reversible and repeatable fashion. In cultured cells, global illumination with blue light rapidly activated Rac and led to cell spreading and membrane ruffling. Localized and pulsed illumination generated a gradient of Rac activity and induced directional migration. In this chapter, we will describe the techniques in detail and present some examples of applications of using photoactivatable Rac (PA-Rac) in living cells.

  19. Inhibition of Rac1 promotes BMP-2-induced osteoblastic differentiation.

    PubMed

    Onishi, M; Fujita, Y; Yoshikawa, H; Yamashita, T

    2013-01-01

    Small G proteins of the Rho family are pivotal regulators of several signaling networks. The Ras homolog family (Rho) and one of its targets, Rho-associated protein kinase (ROCK), participate in a wide variety of biological processes, including bone formation. A previous study has demonstrated that the ROCK inhibitor Y-27632 enhanced bone formation induced by recombinant human bone morphogenetic protein-2 (BMP-2) in vivo and in vitro. However, the effect of other Rho family members, such as Ras-related C3 botulinum toxin substrate 1 (Rac1) and cell division cycle 42 (Cdc42), on bone formation remains unknown. In this study, we investigated whether Rac1 also participates in BMP-2-induced osteogenesis. Expression of a dominant-negative mutant of Rac1 enhanced BMP-2-induced osteoblastic differentiation in C2C12 cells, whereas a constitutively active mutant of Rac1 attenuated that effect. Knockdown of T-lymphoma invasion and metastasis 1 (Tiam1), a Rac-specific guanine nucleotide exchange factor, enhanced BMP-2-induced alkaline phosphatase activity. Further, we demonstrated that BMP-2 stimulated Rac1 activity. These results indicate that the activation of Rac1 attenuates osteoblastic differentiation in C2C12 cells.

  20. Rac1 modulates cardiomyocyte adhesion during mouse embryonic development

    SciTech Connect

    Abu-Issa, Radwan

    2015-01-24

    Highlights: • Conditional knockout of Rac1 using Nkx2.5 Cre line is lethal at E13.5. • The myocardium of the mutant is thin and disorganized. • The phenotype is not due to cardiomyocyte low proliferation or apoptosis. • The phenotype is due to specific defect in cardiomyocyte adhesion. - Abstract: Rac1, a member of the Rho subfamily of small GTPases, is involved in morphogenesis and differentiation of many cell types. Here we define a role of Rac1 in cardiac development by specifically deleting Rac1 in the pre-cardiac mesoderm using the Nkx2.5-Cre transgenic driver line. Rac1-conditional knockout embryos initiate heart development normally until embryonic day 11.5 (E11.5); their cardiac mesoderm is specified, and the heart tube is formed and looped. However, by E12.5-E13.5 the mutant hearts start failing and embryos develop edema and hemorrhage which is probably the cause for the lethality observed soon after. The hearts of Rac1-cKO embryos exhibit disorganized and thin myocardial walls and defects in outflow tract alignment. No significant differences of cardiomyocyte death or proliferation were found between developing control and mutant embryos. To uncover the role of Rac1 in the heart, E11.5 primary heart cells were cultured and analyzed in vitro. Rac1-deficient cardiomyocytes were less spread, round and loosely attached to the substrate and to each other implying that Rac1-mediated signaling is required for appropriate cell–cell and/or cellmatrix adhesion during cardiac development.

  1. Loss of Either Rac1 or Rac3 GTPase Differentially Affects the Behavior of Mutant Mice and the Development of Functional GABAergic Networks

    PubMed Central

    Pennucci, Roberta; Talpo, Francesca; Astro, Veronica; Montinaro, Valentina; Morè, Lorenzo; Cursi, Marco; Castoldi, Valerio; Chiaretti, Sara; Bianchi, Veronica; Marenna, Silvia; Cambiaghi, Marco; Tonoli, Diletta; Leocani, Letizia; Biella, Gerardo; D'Adamo, Patrizia; de Curtis, Ivan

    2016-01-01

    Rac GTPases regulate the development of cortical/hippocampal GABAergic interneurons by affecting the early development and migration of GABAergic precursors. We have addressed the function of Rac1 and Rac3 proteins during the late maturation of hippocampal interneurons. We observed specific phenotypic differences between conditional Rac1 and full Rac3 knockout mice. Rac1 deletion caused greater generalized hyperactivity and cognitive impairment compared with Rac3 deletion. This phenotype matched with a more evident functional impairment of the inhibitory circuits in Rac1 mutants, showing higher excitability and reduced spontaneous inhibitory currents in the CA hippocampal pyramidal neurons. Morphological analysis confirmed a differential modification of the inhibitory circuits: deletion of either Rac caused a similar reduction of parvalbumin-positive inhibitory terminals in the pyramidal layer. Intriguingly, cannabinoid receptor-1-positive terminals were strongly increased only in the CA1 of Rac1-depleted mice. This increase may underlie the stronger electrophysiological defects in this mutant. Accordingly, incubation with an antagonist for cannabinoid receptors partially rescued the reduction of spontaneous inhibitory currents in the pyramidal cells of Rac1 mutants. Our results show that Rac1 and Rac3 have independent roles in the formation of GABAergic circuits, as highlighted by the differential effects of their deletion on the late maturation of specific populations of interneurons. PMID:26582364

  2. Loss of Either Rac1 or Rac3 GTPase Differentially Affects the Behavior of Mutant Mice and the Development of Functional GABAergic Networks.

    PubMed

    Pennucci, Roberta; Talpo, Francesca; Astro, Veronica; Montinaro, Valentina; Morè, Lorenzo; Cursi, Marco; Castoldi, Valerio; Chiaretti, Sara; Bianchi, Veronica; Marenna, Silvia; Cambiaghi, Marco; Tonoli, Diletta; Leocani, Letizia; Biella, Gerardo; D'Adamo, Patrizia; de Curtis, Ivan

    2016-02-01

    Rac GTPases regulate the development of cortical/hippocampal GABAergic interneurons by affecting the early development and migration of GABAergic precursors. We have addressed the function of Rac1 and Rac3 proteins during the late maturation of hippocampal interneurons. We observed specific phenotypic differences between conditional Rac1 and full Rac3 knockout mice. Rac1 deletion caused greater generalized hyperactivity and cognitive impairment compared with Rac3 deletion. This phenotype matched with a more evident functional impairment of the inhibitory circuits in Rac1 mutants, showing higher excitability and reduced spontaneous inhibitory currents in the CA hippocampal pyramidal neurons. Morphological analysis confirmed a differential modification of the inhibitory circuits: deletion of either Rac caused a similar reduction of parvalbumin-positive inhibitory terminals in the pyramidal layer. Intriguingly, cannabinoid receptor-1-positive terminals were strongly increased only in the CA1 of Rac1-depleted mice. This increase may underlie the stronger electrophysiological defects in this mutant. Accordingly, incubation with an antagonist for cannabinoid receptors partially rescued the reduction of spontaneous inhibitory currents in the pyramidal cells of Rac1 mutants. Our results show that Rac1 and Rac3 have independent roles in the formation of GABAergic circuits, as highlighted by the differential effects of their deletion on the late maturation of specific populations of interneurons.

  3. 76 FR 16603 - Butte County Resource Advisory Committee (RAC); Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-24

    ... eataylor@fs.fed.us . Other RAC information may be obtained at http://www.fs.usda.gov and http://www.fs.fed.us/srs . Dated: March 18, 2011. Matt Janowiak, Acting Deputy Forest Supervisor. BILLING CODE P...

  4. The small GTPase Rac1 regulates auditory hair cell morphogenesis

    PubMed Central

    Grimsley-Myers, Cynthia M.; Sipe, Conor W.; Géléoc, Gwenaëllle S.G.; Lu, Xiaowei

    2010-01-01

    Morphogenesis of sensory hair cells, in particular their mechanotransduction organelle, the stereociliary bundle, requires highly organized remodeling of the actin cytoskeleton. The roles of Rho family small GTPases during this process remain unknown. Here we show that deletion of Rac1 in the otic epithelium resulted in severe defects in cochlear epithelial morphogenesis. The mutant cochlea was severely shortened with a reduced number of auditory hair cells and cellular organization of the auditory sensory epithelium was abnormal. Rac1 mutant hair cells also displayed defects in planar cell polarity and morphogenesis of the stereociliary bundle, including bundle fragmentation or deformation, and mispositioning or absence of the kinocilium. We further demonstrate that a Rac-PAK signaling pathway mediates kinocilium-stereocilia interactions and is required for cohesion of the stereociliary bundle. Together, these results reveal a critical function of Rac1 in morphogenesis of the auditory sensory epithelium and stereociliary bundle. PMID:20016102

  5. 76 FR 9540 - Humboldt County Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-18

    ... Rivers National Forest Office, 1330 Bayshore Way, Eureka, CA 95501. FOR FURTHER INFORMATION CONTACT: Adam...: Notice of meeting. SUMMARY: The Humboldt County Resource Advisory Committee (RAC) will meet in...

  6. 76 FR 14897 - Humboldt County Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... Rivers National Forest Office, 1330 Bayshore Way, Eureka, CA 95501. FOR FURTHER INFORMATION CONTACT: Adam...: Notice of meeting. SUMMARY: The Humboldt County Resource Advisory Committee (RAC) will meet in...

  7. Characterization of EHop-016, novel small molecule inhibitor of Rac GTPase.

    PubMed

    Montalvo-Ortiz, Brenda L; Castillo-Pichardo, Linette; Hernández, Eliud; Humphries-Bickley, Tessa; De la Mota-Peynado, Alina; Cubano, Luis A; Vlaar, Cornelis P; Dharmawardhane, Suranganie

    2012-04-13

    The Rho GTPase Rac regulates actin cytoskeleton reorganization to form cell surface extensions (lamellipodia) required for cell migration/invasion during cancer metastasis. Rac hyperactivation and overexpression are associated with aggressive cancers; thus, interference of the interaction of Rac with its direct upstream activators, guanine nucleotide exchange factors (GEFs), is a viable strategy for inhibiting Rac activity. We synthesized EHop-016, a novel inhibitor of Rac activity, based on the structure of the established Rac/Rac GEF inhibitor NSC23766. Herein, we demonstrate that EHop-016 inhibits Rac activity in the MDA-MB-435 metastatic cancer cells that overexpress Rac and exhibits high endogenous Rac activity. The IC(50) of 1.1 μM for Rac inhibition by EHop-016 is ∼100-fold lower than for NSC23766. EHop-016 is specific for Rac1 and Rac3 at concentrations of ≤5 μM. At higher concentrations, EHop-016 inhibits the close homolog Cdc42. In MDA-MB-435 cells that demonstrate high active levels of the Rac GEF Vav2, EHop-016 inhibits the association of Vav2 with a nucleotide-free Rac1(G15A), which has a high affinity for activated GEFs. EHop-016 also inhibits the Rac activity of MDA-MB-231 metastatic breast cancer cells and reduces Rac-directed lamellipodia formation in both cell lines. EHop-016 decreases Rac downstream effects of PAK1 (p21-activated kinase 1) activity and directed migration of metastatic cancer cells. Moreover, at effective concentrations (<5 μM), EHop-016 does not affect the viability of transformed mammary epithelial cells (MCF-10A) and reduces viability of MDA-MB-435 cells by only 20%. Therefore, EHop-016 holds promise as a targeted therapeutic agent for the treatment of metastatic cancers with high Rac activity.

  8. Rational design and applications of a Rac GTPase-specific small molecule inhibitor.

    PubMed

    Akbar, Huzoor; Cancelas, Jose; Williams, David A; Zheng, Jie; Zheng, Yi

    2006-01-01

    Rac GTPases are involved in the regulation of multiple cell functions and have been implicated in the pathology of certain human diseases. Dominant negative mutants of Rac have been the tool of choice in studying Rac function in cells. Given the difficulty of introducing high concentrations of the Rac mutants into primary cells and nonspecific effects of the mutants on Rho guanine nucleotide exchange factor (GEF) activities, it is desirable to develop small molecule inhibitors that could specifically inhibit Rac activities. Here we describe the rational design, characterization, and applications of a first-generation Rac-specific small molecule inhibitor. On the basis of the structure-function information of Rac interaction with GEFs, in a computer-based virtual screening we have identified NSC23766, a highly soluble and membrane permeable compound, as a specific inhibitor of a subset of GEF binding to Rac and, therefore, Rac activation by these GEFs. In fibroblast cells, NSC23766 inhibited Rac1 GTP-loading without affecting Cdc42 or RhoA activity and suppressed cell proliferation induced by a Rac GEF Tiam1. It has little effect on cell growth induced by a constitutively active Rac1 mutant. In addition, NSC23766 inhibited: (1) the anchorage-independent growth and invasion phenotypes of human prostate cancer PC-3 cells; (2) Rac activation and Rac-dependent aggregation of platelets stimulated by thrombin; and (3) Rac1 and Rac2 activities of hematopoietic stem/progenitor cells and induced their mobilization from mouse bone marrow to peripheral blood. Thus, NSC23766 is a lead small molecule inhibitor of Rac activity and could be useful for studying Rac-mediated cellular functions and for modulating pathological conditions in which Rac-deregulation may play a role.

  9. Contractor Accountability Act

    THOMAS, 111th Congress

    Rep. Sutton, Betty [D-OH-13

    2009-03-05

    05/04/2009 Referred to the Subcommittee on Government Management, Organization, and Procurement. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  10. Neuronal Rac1 Is Required for Learning-Evoked Neurogenesis

    PubMed Central

    Anderson, Matthew P.; Freewoman, Julia; Cord, Branden; Babu, Harish; Brakebusch, Cord

    2013-01-01

    Hippocampus-dependent learning and memory relies on synaptic plasticity as well as network adaptations provided by the addition of adult-born neurons. We have previously shown that activity-induced intracellular signaling through the Rho family small GTPase Rac1 is necessary in forebrain projection neurons for normal synaptic plasticity in vivo, and here we show that selective loss of neuronal Rac1 also impairs the learning-evoked increase in neurogenesis in the adult mouse hippocampus. Earlier work has indicated that experience elevates the abundance of adult-born neurons in the hippocampus primarily by enhancing the survival of neurons produced just before the learning event. Loss of Rac1 in mature projection neurons did reduce learning-evoked neurogenesis but, contrary to our expectations, these effects were not mediated by altering the survival of young neurons in the hippocampus. Instead, loss of neuronal Rac1 activation selectively impaired a learning-evoked increase in the proliferation and accumulation of neural precursors generated during the learning event itself. This indicates that experience-induced alterations in neurogenesis can be mechanistically resolved into two effects: (1) the well documented but Rac1-independent signaling cascade that enhances the survival of young postmitotic neurons; and (2) a previously unrecognized Rac1-dependent signaling cascade that stimulates the proliferative production and retention of new neurons generated during learning itself. PMID:23884931

  11. Adhesion-related kinase induction of migration requires phosphatidylinositol-3-kinase and ras stimulation of rac activity in immortalized gonadotropin-releasing hormone neuronal cells.

    PubMed

    Nielsen-Preiss, Sheila M; Allen, Melissa P; Xu, Mei; Linseman, Daniel A; Pawlowski, John E; Bouchard, R J; Varnum, Brian C; Heidenreich, Kim A; Wierman, Margaret E

    2007-06-01

    GnRH neurons migrate into the hypothalamus during development. Although migratory defects may result in disordered activation of the reproductive axis and lead to delayed or absent sexual maturation, specific factors regulating GnRH neuronal migration remain largely unknown. The receptor tyrosine kinase, adhesion-related kinase (Ark) (also known as Axl, UFO, and Tyro7), has been implicated in the migration of GnRH neuronal cells. Binding of its ligand, growth arrest-specific gene 6 (Gas6), promotes cytoskeletal remodeling and migration of NLT GnRH neuronal cells via Rac and p38 MAPK. Here, we examined the Axl effectors proximal to Rac in the signaling pathway. Gas6/Axl-induced lamellipodia formation and migration were blocked after phosphatidylinositol-3-kinase (PI3K) inhibition in GnRH neuronal cells. The p85 subunit of PI3K coimmunoprecipitated with Axl and was phosphorylated in a Gas6-sensitive manner. In addition, PI3K inhibition in GnRH neuronal cells diminished Gas6-induced Rac activation. Exogenous expression of a dominant-negative form of Ras also decreased GnRH neuronal lamellipodia formation, migration, and Rac activation. PI3K inhibition blocked Ras in addition to Rac activation and migration. In contrast, pharmacological blockade of the phospholipase C gamma effectors, protein kinase C or calcium/calmodulin protein kinase II, had no effect on Gas6/Axl signaling to promote Rac activation or stimulate cytoskeletal reorganization and migration. Together, these data show that the PI3K-Ras pathway is a major mediator of Axl actions upstream of Rac to induce GnRH neuronal cell migration. PMID:17332061

  12. Novel Activities of Select NSAID R-Enantiomers against Rac1 and Cdc42 GTPases.

    PubMed

    Oprea, Tudor I; Sklar, Larry A; Agola, Jacob O; Guo, Yuna; Silberberg, Melina; Roxby, Joshua; Vestling, Anna; Romero, Elsa; Surviladze, Zurab; Murray-Krezan, Cristina; Waller, Anna; Ursu, Oleg; Hudson, Laurie G; Wandinger-Ness, Angela

    2015-01-01

    Rho family GTPases (including Rac, Rho and Cdc42) collectively control cell proliferation, adhesion and migration and are of interest as functional therapeutic targets in numerous epithelial cancers. Based on high throughput screening of the Prestwick Chemical Library® and cheminformatics we identified the R-enantiomers of two approved drugs (naproxen and ketorolac) as inhibitors of Rac1 and Cdc42. The corresponding S-enantiomers are considered the active component in racemic drug formulations, acting as non-steroidal anti-inflammatory drugs (NSAIDs) with selective activity against cyclooxygenases. Here, we show that the S-enantiomers of naproxen and ketorolac are inactive against the GTPases. Additionally, more than twenty other NSAIDs lacked inhibitory action against the GTPases, establishing the selectivity of the two identified NSAIDs. R-naproxen was first identified as a lead compound and tested in parallel with its S-enantiomer and the non-chiral 6-methoxy-naphthalene acetic acid (active metabolite of nabumetone, another NSAID) as a structural series. Cheminformatics-based substructure analyses-using the rotationally constrained carboxylate in R-naproxen-led to identification of racemic [R/S] ketorolac as a suitable FDA-approved candidate. Cell based measurement of GTPase activity (in animal and human cell lines) demonstrated that the R-enantiomers specifically inhibit epidermal growth factor stimulated Rac1 and Cdc42 activation. The GTPase inhibitory effects of the R-enantiomers in cells largely mimic those of established Rac1 (NSC23766) and Cdc42 (CID2950007/ML141) specific inhibitors. Docking predicts that rotational constraints position the carboxylate moieties of the R-enantiomers to preferentially coordinate the magnesium ion, thereby destabilizing nucleotide binding to Rac1 and Cdc42. The S-enantiomers can be docked but are less favorably positioned in proximity to the magnesium. R-naproxen and R-ketorolac have potential for rapid translation and

  13. Novel Activities of Select NSAID R-Enantiomers against Rac1 and Cdc42 GTPases.

    PubMed

    Oprea, Tudor I; Sklar, Larry A; Agola, Jacob O; Guo, Yuna; Silberberg, Melina; Roxby, Joshua; Vestling, Anna; Romero, Elsa; Surviladze, Zurab; Murray-Krezan, Cristina; Waller, Anna; Ursu, Oleg; Hudson, Laurie G; Wandinger-Ness, Angela

    2015-01-01

    Rho family GTPases (including Rac, Rho and Cdc42) collectively control cell proliferation, adhesion and migration and are of interest as functional therapeutic targets in numerous epithelial cancers. Based on high throughput screening of the Prestwick Chemical Library® and cheminformatics we identified the R-enantiomers of two approved drugs (naproxen and ketorolac) as inhibitors of Rac1 and Cdc42. The corresponding S-enantiomers are considered the active component in racemic drug formulations, acting as non-steroidal anti-inflammatory drugs (NSAIDs) with selective activity against cyclooxygenases. Here, we show that the S-enantiomers of naproxen and ketorolac are inactive against the GTPases. Additionally, more than twenty other NSAIDs lacked inhibitory action against the GTPases, establishing the selectivity of the two identified NSAIDs. R-naproxen was first identified as a lead compound and tested in parallel with its S-enantiomer and the non-chiral 6-methoxy-naphthalene acetic acid (active metabolite of nabumetone, another NSAID) as a structural series. Cheminformatics-based substructure analyses-using the rotationally constrained carboxylate in R-naproxen-led to identification of racemic [R/S] ketorolac as a suitable FDA-approved candidate. Cell based measurement of GTPase activity (in animal and human cell lines) demonstrated that the R-enantiomers specifically inhibit epidermal growth factor stimulated Rac1 and Cdc42 activation. The GTPase inhibitory effects of the R-enantiomers in cells largely mimic those of established Rac1 (NSC23766) and Cdc42 (CID2950007/ML141) specific inhibitors. Docking predicts that rotational constraints position the carboxylate moieties of the R-enantiomers to preferentially coordinate the magnesium ion, thereby destabilizing nucleotide binding to Rac1 and Cdc42. The S-enantiomers can be docked but are less favorably positioned in proximity to the magnesium. R-naproxen and R-ketorolac have potential for rapid translation and

  14. Novel Activities of Select NSAID R-Enantiomers against Rac1 and Cdc42 GTPases

    PubMed Central

    Oprea, Tudor I.; Sklar, Larry A.; Agola, Jacob O.; Guo, Yuna; Silberberg, Melina; Roxby, Joshua; Vestling, Anna; Romero, Elsa; Surviladze, Zurab; Murray-Krezan, Cristina; Waller, Anna; Ursu, Oleg; Hudson, Laurie G.; Wandinger-Ness, Angela

    2015-01-01

    Rho family GTPases (including Rac, Rho and Cdc42) collectively control cell proliferation, adhesion and migration and are of interest as functional therapeutic targets in numerous epithelial cancers. Based on high throughput screening of the Prestwick Chemical Library® and cheminformatics we identified the R-enantiomers of two approved drugs (naproxen and ketorolac) as inhibitors of Rac1 and Cdc42. The corresponding S-enantiomers are considered the active component in racemic drug formulations, acting as non-steroidal anti-inflammatory drugs (NSAIDs) with selective activity against cyclooxygenases. Here, we show that the S-enantiomers of naproxen and ketorolac are inactive against the GTPases. Additionally, more than twenty other NSAIDs lacked inhibitory action against the GTPases, establishing the selectivity of the two identified NSAIDs. R-naproxen was first identified as a lead compound and tested in parallel with its S-enantiomer and the non-chiral 6-methoxy-naphthalene acetic acid (active metabolite of nabumetone, another NSAID) as a structural series. Cheminformatics-based substructure analyses—using the rotationally constrained carboxylate in R-naproxen—led to identification of racemic [R/S] ketorolac as a suitable FDA-approved candidate. Cell based measurement of GTPase activity (in animal and human cell lines) demonstrated that the R-enantiomers specifically inhibit epidermal growth factor stimulated Rac1 and Cdc42 activation. The GTPase inhibitory effects of the R-enantiomers in cells largely mimic those of established Rac1 (NSC23766) and Cdc42 (CID2950007/ML141) specific inhibitors. Docking predicts that rotational constraints position the carboxylate moieties of the R-enantiomers to preferentially coordinate the magnesium ion, thereby destabilizing nucleotide binding to Rac1 and Cdc42. The S-enantiomers can be docked but are less favorably positioned in proximity to the magnesium. R-naproxen and R-ketorolac have potential for rapid translation and

  15. Rac GTPases play critical roles in early T-cell development

    PubMed Central

    Dumont, Celine; Corsoni-Tadrzak, Agnieszka; Ruf, Sandra; de Boer, Jasper; Williams, Adam; Turner, Martin; Kioussis, Dimitris

    2009-01-01

    The Rac1 and Rac2 GTPases play important roles in many processes including cytoskeletal reorganization, proliferation, and survival, and are required for B-cell development. Previous studies had shown that deficiency in Rac2 did not affect T-cell development, whereas the function of Rac1 in this process has not been investigated. We now show that simultaneous absence of both GTPases resulted in a very strong developmental block at the pre-TCR checkpoint and in defective positive selection. Unexpectedly, deficiency of Rac1 and Rac2 also resulted in the aberrant survival of thymocytes lacking expression of TCRβ, showing hallmarks of hyperactive Notch signaling. Furthermore, we found a similar novel phenotype in the absence of Vav1, Vav2, and Vav3, which function as guanine nucleotide exchange factors for Rac1 and Rac2. These results show that a pathway containing Vav and Rac proteins may negatively regulate Notch signaling during early thymic development. PMID:19088377

  16. Rac1 expression in epithelial ovarian cancer: effect on cell EMT and clinical outcome.

    PubMed

    Leng, Ruobing; Liao, Gang; Wang, Haixia; Kuang, Jun; Tang, Liangdan

    2015-02-01

    Ras-related C3 botulinum toxin substrate 1 (rac1) has been implicated in tumor epithelial-mesenchymal transition (EMT); however, limited information is available regarding the role of rac1 in epithelial ovarian cancer (EOC). This study aimed to evaluate the correlation of rac1 expression with EMT and EOC prognosis. Rac1 protein levels of 150 EOC specimens were evaluated by immunohistochemical staining. Survival analysis was performed to determine the correlation between rac1 expression and survival. Cellular and molecular changes were also examined after rac1 in ovarian cancer cells was silenced in vitro and in vivo. The mechanism of rac1 on EMT was investigated by Western blot analysis. Rac1 was highly expressed in EOC. Rac1 overexpression was closely associated with advanced stage based on International Federation of Gynecology and Obstetrics, poor grade, serum Ca-125, and residual tumor size. Survival analyses demonstrated that patients with high rac1 expression levels were more susceptible to early tumor recurrence with very poor prognosis. This study revealed that rac1 downregulation decreased cell EMT and proliferation capability in vitro and in vivo. Rac1 expression possibly altered cell EMT by interacting with p21-activated kinase 1 and p38 mitogen-activated protein kinase signaling pathways. The present study showed that rac1 overexpression is associated with cell EMT and poor EOC prognosis. Rac1 possibly plays an important role in predicting EOC metastasis.

  17. Rac1 expression in epithelial ovarian cancer: effect on cell EMT and clinical outcome.

    PubMed

    Leng, Ruobing; Liao, Gang; Wang, Haixia; Kuang, Jun; Tang, Liangdan

    2015-02-01

    Ras-related C3 botulinum toxin substrate 1 (rac1) has been implicated in tumor epithelial-mesenchymal transition (EMT); however, limited information is available regarding the role of rac1 in epithelial ovarian cancer (EOC). This study aimed to evaluate the correlation of rac1 expression with EMT and EOC prognosis. Rac1 protein levels of 150 EOC specimens were evaluated by immunohistochemical staining. Survival analysis was performed to determine the correlation between rac1 expression and survival. Cellular and molecular changes were also examined after rac1 in ovarian cancer cells was silenced in vitro and in vivo. The mechanism of rac1 on EMT was investigated by Western blot analysis. Rac1 was highly expressed in EOC. Rac1 overexpression was closely associated with advanced stage based on International Federation of Gynecology and Obstetrics, poor grade, serum Ca-125, and residual tumor size. Survival analyses demonstrated that patients with high rac1 expression levels were more susceptible to early tumor recurrence with very poor prognosis. This study revealed that rac1 downregulation decreased cell EMT and proliferation capability in vitro and in vivo. Rac1 expression possibly altered cell EMT by interacting with p21-activated kinase 1 and p38 mitogen-activated protein kinase signaling pathways. The present study showed that rac1 overexpression is associated with cell EMT and poor EOC prognosis. Rac1 possibly plays an important role in predicting EOC metastasis. PMID:25585684

  18. Independent contractor arrangements and IRS audits.

    PubMed

    Pelfrey, S; Theisen, B A

    1995-01-01

    As government auditors begin their challenges, nurse executives need to review their operations to remove any potential audit risks. Although a common practice for many institutions, the use of independent contractor arrangements may be ruled inappropriate. As a result, many individuals may be reclassified as employees, leading to Internal Revenue Service (IRS) assessments of penalties and back payroll taxes. It always is prudent to anticipate IRS actions and shore up any areas that may lead to tax assessments before they are imposed on the institution.

  19. Overseas Contractor Reform Act

    THOMAS, 111th Congress

    Rep. Welch, Peter [D-VT-At Large

    2010-05-20

    09/16/2010 Received in the Senate and Read twice and referred to the Committee on Homeland Security and Governmental Affairs. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

  20. Debarment and suspension. [of contractors

    NASA Technical Reports Server (NTRS)

    Whelan, Thomas J.

    1987-01-01

    The changing Government attitude toward contractor debarment and suspension is examined, with emphasis on the fact that the Government is more alert to fraud, waste, and abuse. Consideration is given to causes of debarment or suspension, procedures and due process hearings, settlement agreements, compliance programs, and recent related legislation. It is concluded that the change in the Government contracting environment in recent years should be sufficient incentive for contractors to monitor their operations more closely.

  1. Regulating Rac in the Nervous System: Molecular Function and Disease Implication of Rac GEFs and GAPs

    PubMed Central

    Bai, Yanyang; Xiang, Xiaoliang; Liang, Chunmei

    2015-01-01

    Rho family GTPases, including RhoA, Rac1, and Cdc42 as the most studied members, are master regulators of actin cytoskeletal organization. Rho GTPases control various aspects of the nervous system and are associated with a number of neuropsychiatric and neurodegenerative diseases. The activity of Rho GTPases is controlled by two families of regulators, guanine nucleotide exchange factors (GEFs) as the activators and GTPase-activating proteins (GAPs) as the inhibitors. Through coordinated regulation by GEFs and GAPs, Rho GTPases act as converging signaling molecules that convey different upstream signals in the nervous system. So far, more than 70 members of either GEFs or GAPs of Rho GTPases have been identified in mammals, but only a small subset of them have well-known functions. Thus, characterization of important GEFs and GAPs in the nervous system is crucial for the understanding of spatiotemporal dynamics of Rho GTPase activity in different neuronal functions. In this review, we summarize the current understanding of GEFs and GAPs for Rac1, with emphasis on the molecular function and disease implication of these regulators in the nervous system. PMID:25879033

  2. Confirmatory radiological survey of the Grand Junction Projects Office Remedial Action Project exterior portions, 1989-1995

    SciTech Connect

    Forbes, G.H.; Egidi, P.V.

    1997-04-01

    The purpose of this independent assessment was to provide the U.S. Department of Energy (DOE) with an independent verification (IV) that the soil at the Grand Junction Projects Office (GJPO) complies with applicable DOE guidelines. Oak Ridge National Laboratory/ Environmental Technology Section (ORNL/ETS) which is also located at the GJPO, was assigned by DOE as the Independent Verification Contractor (IVC). The assessment included reviews of the decontamination and decommissioning plan, annual environmental monitoring reports, data in the pre- and post-remedial action reports, reassessment reports and IV surveys. Procedures and field methods used during the remediation were reviewed, commented on, and amended as needed. The IV surveys included beta-gamma and gamma radiation scans, soil sampling and analyses. Based on the data presented in the post-remedial action report and the results of the IV surveys, the remediation of the outdoor portions of the GJPO has achieved the objectives. Residual deposits of uranium contamination may exist under asphalt because the original characterization was not designed to identify uranium and subsequent investigations were limited. The IVC recommends that this be addressed with the additional remediation. The IVC is working with the remedial action contractor (RAC) to assure that final documentation WM be sufficient for certification. The IVC will address additional remediation of buildings, associated utilities, and groundwater in separate reports. Therefore, this is considered a partial verification.

  3. Cocaine activates Rac1 to control structural and behavioral plasticity in caudate putamen.

    PubMed

    Li, Juan; Zhang, Lei; Chen, Zhenzhong; Xie, Minjuan; Huang, Lu; Xue, Jinhua; Liu, Yutong; Liu, Nuyun; Guo, Fukun; Zheng, Yi; Kong, Jiming; Zhang, Lin; Zhang, Lu

    2015-03-01

    Repeated exposure to cocaine was previously found to cause sensitized behavioral responses and structural remodeling on medium spiny neurons of the nucleus accumbens (NAc) and caudate putamen (CPu). Rac1 has emerged as a key integrator of environmental cues that regulates dendritic cytoskeletons. In this study, we investigated the role of Rac1 in cocaine-induced dendritic and behavioral plasticity in the CPu. We found that Rac1 activation was reduced in the NAc but increased in the CPu following repeated cocaine treatment. Inhibition of Rac1 activity by a Rac1-specific inhibitor NSC23766, overexpression of a dominant negative mutant of Rac1 (T17N-Rac1) or local knockout of Rac1 attenuated the cocaine-induced increase in dendrites and spine density in the CPu, whereas overexpression of a constitutively active Rac1 exert the opposite effect. Moreover, NSC23766 reversed the increased number of asymmetric spine synapses in the CPu following chronic cocaine exposure. Downregulation of Rac1 activity likewise attenuates behavioral reward responses to cocaine exposure, with activation of Rac1 producing the opposite effect. Thus, Rac1 signaling is differentially regulated in the NAc and CPu after repeated cocaine treatment, and induction of Rac1 activation in the CPu is important for cocaine exposure-induced dendritic remodeling and behavioral plasticity.

  4. Rac1 signaling modulates BCL-6-mediated repression of gene transcription.

    PubMed

    Barros, Patrícia; Jordan, Peter; Matos, Paulo

    2009-08-01

    Rac1 is a member of the Rho family of small GTPases that not only regulates signaling pathways involved in cell adhesion and migration but also regulates gene transcription. Here we show that the transcriptional repressor BCL-6 is regulated by Rac1 signaling. Transfection of active Rac1 mutants into colorectal DLD-1 cells led to increased expression of a BCL-6-controlled luciferase reporter construct. Conversely, inhibition of endogenous Rac1 activation by the Rac1 inhibitor NSC23766 decreased reporter activity. Moreover, BCL-6 lost its typical localization to nuclear dots upon activation of Rac1 and became predominantly soluble in a non-chromatin-bound cell fraction. Rac1 signaling also regulated the expression of endogenous BCL-6-regulated genes, including the p50 precursor NF-kappaB1/p105 and the cell adhesion molecule CD44. Interestingly, these effects were not stimulated by the alternative splice variant Rac1b. The mechanism of BCL-6 inhibition does not involve formation of a stable Rac1/BCL-6 complex and is independent of Rac-induced reactive oxygen species production or Jun NH(2)-terminal kinase activation. We show that PAK1 mediates inhibition downstream of Rac and can directly phosphorylate BCL-6. Together, these data provide substantial evidence that Rac1 signaling inhibits the transcriptional repressor BCL-6 in colorectal cells and reveal a novel pathway that links Rac1 signaling to the regulation of gene transcription.

  5. Rac regulates vascular endothelial growth factor stimulated motility.

    PubMed

    Soga, N; Connolly, J O; Chellaiah, M; Kawamura, J; Hruska, K A

    2001-01-01

    During angiogenesis endothelial cells migrate towards a chemotactic stimulus. Understanding the mechanism of endothelial cell migration is critical to the therapeutic manipulation of angiogenesis and ultimately cancer prevention. Vascular endothelial growth factor (VEGF) is a potent chemotactic stimulus of endothelial cells during angiogenesis. The endothelial cell signal transduction pathway of VEGF represents a potential target for cancer therapy, but the mechanisms of post-receptor signal transduction including the roles of rho family GTPases in regulating the cytoskeletal effects of VEGF in endothelial cells are not understood. Here we analyze the mechanisms of cell migration in the mouse brain endothelial cell line (bEND3). Stable transfectants containing a tetracycline repressible expression vector were used to induce expression of Rac mutants. Endothelial cell haptotaxis was stimulated by constitutively active V12Rac on collagen and vitronectin coated supports, and chemotaxis was further stimulated by VEGF. Osteopontin coated supports were the most stimulatory to bEND3 haptotaxis, but VEGF was not effective in further increasing migration on osteopontin coated supports. Haptotaxis on support coated with collagen, vitronectin, and to a lesser degree osteopontin was inhibited by N17 Rac. N17 Rac expression blocked stimulation of endothelial cell chemotaxis by VEGF. As part of the chemotactic stimulation, VEGF caused a loss of actin organization at areas of cell-cell contact and increased stress fiber expression in endothelial cells which were directed towards pores in the transwell membrane. N17 Rac prevented the stimulation of cell-cell contact disruption and the stress fiber stimulation by VEGF. These data demonstrate two pathways of regulating endothelial cell motility, one in which Rac is activated by matrix/integrin stimulation and is a crucial modulator of endothelial cell haptotaxis. The other pathway, in the presence of osteopontin, is Rac independent

  6. Rac regulates vascular endothelial growth factor stimulated motility.

    PubMed

    Soga, N; Connolly, J O; Chellaiah, M; Kawamura, J; Hruska, K A

    2001-01-01

    During angiogenesis endothelial cells migrate towards a chemotactic stimulus. Understanding the mechanism of endothelial cell migration is critical to the therapeutic manipulation of angiogenesis and ultimately cancer prevention. Vascular endothelial growth factor (VEGF) is a potent chemotactic stimulus of endothelial cells during angiogenesis. The endothelial cell signal transduction pathway of VEGF represents a potential target for cancer therapy, but the mechanisms of post-receptor signal transduction including the roles of rho family GTPases in regulating the cytoskeletal effects of VEGF in endothelial cells are not understood. Here we analyze the mechanisms of cell migration in the mouse brain endothelial cell line (bEND3). Stable transfectants containing a tetracycline repressible expression vector were used to induce expression of Rac mutants. Endothelial cell haptotaxis was stimulated by constitutively active V12Rac on collagen and vitronectin coated supports, and chemotaxis was further stimulated by VEGF. Osteopontin coated supports were the most stimulatory to bEND3 haptotaxis, but VEGF was not effective in further increasing migration on osteopontin coated supports. Haptotaxis on support coated with collagen, vitronectin, and to a lesser degree osteopontin was inhibited by N17 Rac. N17 Rac expression blocked stimulation of endothelial cell chemotaxis by VEGF. As part of the chemotactic stimulation, VEGF caused a loss of actin organization at areas of cell-cell contact and increased stress fiber expression in endothelial cells which were directed towards pores in the transwell membrane. N17 Rac prevented the stimulation of cell-cell contact disruption and the stress fiber stimulation by VEGF. These data demonstrate two pathways of regulating endothelial cell motility, one in which Rac is activated by matrix/integrin stimulation and is a crucial modulator of endothelial cell haptotaxis. The other pathway, in the presence of osteopontin, is Rac independent

  7. Technical Assistance Contractor management plan. Revision 1

    SciTech Connect

    1995-08-01

    The Technical Assistance Contractor (TAC) for the Uranium Mill Tailings Remedial Action (UMTRA) Project comprises Jacobs Engineering Group Inc. (JEG) as the prime contractor and three teaming partner subcontractors: Roy F. Weston, Inc. (RFW), AGRA Earth and Environmental, Inc. (AGRA), and Geraghty and Miller, Inc. (G and M). The TAC contract`s scope is to provide technical, analytical, environmental, engineering, design, inspection, and management support services to the US Department of Energy (DOE) for both Surface and Ground Water Projects. The TAC team supports the DOE in completing surface remedial action and initiating ground water remediation work for start-up, characterization, compliance planning, design, construction oversight, and remedial operations. The TAC provides the DOE UMTRA Project Team with a dedicated management, scientific, and technical resource base in Albuquerque, New Mexico, which is supplemented by corporate resources. A carefully developed and maintained staff of technical experts is available to assess, analyze, develop, and execute cost-effective solutions to the demanding technical and institutional problems presented by the UMTRA Project.

  8. 77 FR 29635 - Access to Confidential Business Information by Several Student Services Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-18

    ... AGENCY Access to Confidential Business Information by Several Student Services Contractors AGENCY: Environmental Protection Agency (EPA). ACTION: Notice. SUMMARY: EPA will be authorizing several Student Services contractors to access information which has been submitted to EPA under all sections of the Toxic...

  9. 78 FR 13394 - 30-Day Notice of Proposed Information Collection: Office of Language Services Contractor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-27

    ... Notice of Proposed Information Collection: Office of Language Services Contractor Application Form ACTION... Language Services Contractor Application Form. OMB Control Number: 1405-0191. Type of Request: Extension of... U.S. Department of State, Office of Language Services, the information collected is used to...

  10. Overexpression of Rac1 in leukemia patients and its role in leukemia cell migration and growth

    SciTech Connect

    Wang, Jiying; Rao, Qing; Wang, Min; Wei, Hui; Xing, Haiyan; Liu, Hang; Wang, Yanzhong; Tang, Kejing; Peng, Leiwen; Tian, Zheng; Wang, Jianxiang

    2009-09-04

    Rac1 belongs to the Rho family that act as critical mediators of signaling pathways controlling cell migration and proliferation and contributes to the interactions of hematopoietic stem cells with their microenvironment. Alteration of Rac1 might result in unbalanced interactions and ultimately lead to leukemogenesis. In this study, we analyze the expression of Rac1 protein in leukemia patients and determine its role in the abnormal behaviours of leukemic cells. Rac1 protein is overexpressed in primary acute myeloid leukemia cells as compared to normal bone marrow mononuclear cells. siRNA-mediated silencing of Rac1 in leukemia cell lines induced inhibition of cell migration, proliferation, and colony formation. Additionally, blocking Rac1 activity by an inhibitor of Rac1-GTPase, NSC23766, suppressed cell migration and growth. We conclude that overexpression of Rac1 contributes to the accelerated migration and high proliferation potential of leukemia cells, which could be implicated in leukemia development and progression.

  11. Essential roles of mgcRacGAP in multilineage differentiation and survival of murine hematopoietic cells

    SciTech Connect

    Yamada, Takayuki; Kurosaki, Tomohiro; Hikida, Masaki

    2008-08-08

    MgcRacGAP, a negative regulator for Rho family GTPases, has been shown to play important roles in cytokinesis using several cell lines. However, the physiological role of mgcRacGAP in multilineage hematopoietic development remains unclear. Here, we conditionally ablated mgcRacGAP in vivo to clarify this issue. As the result, we found that normal hematopoietic development including proliferation and survival requires mgcRacGAP. We also found that depletion of mgcRacGAP in hematopoietic cells results in a marked decrease in c-Kit{sup +}Sca-1{sup +}Lin{sup -} cells, suggesting that mgcRacGAP is required for the maintenance of the hematopoietic stem cells. In addition, B cells in which mgcRacGAP had been selectively ablated showed proliferation failure and fell into apoptosis. Taken together, mgcRacGAP is now shown to play a indispensable role in the development of hematopoietic cells in vivo.

  12. Overexpression of Rac1 in leukemia patients and its role in leukemia cell migration and growth.

    PubMed

    Wang, Jiying; Rao, Qing; Wang, Min; Wei, Hui; Xing, Haiyan; Liu, Hang; Wang, Yanzhong; Tang, Kejing; Peng, Leiwen; Tian, Zheng; Wang, Jianxiang

    2009-09-01

    Rac1 belongs to the Rho family that act as critical mediators of signaling pathways controlling cell migration and proliferation and contributes to the interactions of hematopoietic stem cells with their microenvironment. Alteration of Rac1 might result in unbalanced interactions and ultimately lead to leukemogenesis. In this study, we analyze the expression of Rac1 protein in leukemia patients and determine its role in the abnormal behaviours of leukemic cells. Rac1 protein is overexpressed in primary acute myeloid leukemia cells as compared to normal bone marrow mononuclear cells. siRNA-mediated silencing of Rac1 in leukemia cell lines induced inhibition of cell migration, proliferation, and colony formation. Additionally, blocking Rac1 activity by an inhibitor of Rac1-GTPase, NSC23766, suppressed cell migration and growth. We conclude that overexpression of Rac1 contributes to the accelerated migration and high proliferation potential of leukemia cells, which could be implicated in leukemia development and progression.

  13. 48 CFR 252.229-7004 - Status of contractors as a direct contractor (Spain).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... direct contractor (Spain). 252.229-7004 Section 252.229-7004 Federal Acquisition Regulations System... contractor (Spain). As prescribed in 229.402-70(d), use the following clause: Status of Contractor as a Director Contractor (Spain) (JUN 1997) (a) “Direct Contractor,” as used in this clause, means an...

  14. Rac limits TGF-β-induced VEGF synthesis in osteoblasts.

    PubMed

    Yamamoto, Naohiro; Otsuka, Takanobu; Kondo, Akira; Matsushima-Nishiwaki, Rie; Kuroyanagi, Gen; Kozawa, Osamu; Tokuda, Haruhiko

    2015-04-15

    We previously showed that transforming growth factor-β (TGF-β) stimulates vascular endothelial growth factor (VEGF) synthesis via p44/p42 mitogen-activated protein (MAP) kinase, p38 MAP kinase and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) in osteoblast-like MC3T3-E1 cells. In the present study, we investigated the involvement of Rac, which is a member of the Rho family of small GTPases, in the TGF-β-stimulated VEGF synthesis in MC3T3-E1 cells. TGF-β markedly increased the levels of GTP-bound Rac. NSC23766, a selective inhibitor of Rac-guanine nucleotide exchange factor interaction, significantly increased both the release of VEGF and the mRNA expression levels induced by TGF-β. In addition, the release of VEGF stimulated by TGF-β was amplified in Rac-knock down cells. Meanwhile, SIS3, a specific inhibitor of TGF-β-dependent Smad3 phosphorylation, significantly reduced the TGF-β-stimulated VEGF release. However, the phosphorylation of Smad2 or Smad3 induced by TGF-β was hardly affected by NSC23766. On the other hand, NSC23766 enhanced the TGF-β-induced phosphorylation of p38 MAP kinase without affecting the phosphorylation of p44/p42 MAP kinase or SAPK/JNK. Furthermore, the phosphorylation of p38 MAP kinase induced by TGF-β was markedly upregulated in the Rac-knock down cells. These results strongly suggest that Rac negatively regulates the TGF-β-stimulated VEGF synthesis via the inhibition of p38 MAP kinase in osteoblasts.

  15. Rac is involved in the interkinetic nuclear migration of cortical progenitor cells.

    PubMed

    Minobe, Sayaka; Sakakibara, Akira; Ohdachi, Tomoko; Kanda, Rieko; Kimura, Miyako; Nakatani, Sayaka; Tadokoro, Ryosuke; Ochiai, Wataru; Nishizawa, Yuji; Mizoguchi, Akira; Kawauchi, Takeshi; Miyata, Takaki

    2009-04-01

    The small GTPase Rac regulates neuronal behavior, but whether it also functions in neural progenitor cells has not yet been explored. Here we report that Rac contributes to the regulation of nuclear migration in neocortical progenitor cells. Rac1 is expressed by progenitor cells in a unique spatiotemporal pattern. Cross-sectional immunohistochemical examination revealed intense Rac1 immunoreactivity at the ventricular surface. Similar staining patterns were obtained by immunofluorescence for a Rac-activator, Tiam1, and by reactions to detect the GTP-bound (active) form of Rac. En face inspection of the ventricular surface revealed that apical Rac1 localization was most frequent in M-phase cells, and the endfeet of cells in other cell cycle phases also showed apical Rac1 distribution at lower frequencies. To ask whether progenitor cell behavior prior to and during M phase is Rac-dependent, we monitored individual DiI-labeled progenitor cells live in the presence of a Rac inhibitor, NSC23766. We observed significantly retarded adventricular nuclear migration, as well as cytokinesis failures. Similar inhibitory effects were obtained by forced expression of a dominant-negative Rac1. These results suggest that Rac may play a role in interkinetic nuclear migration in the developing mouse brain.

  16. 77 FR 17098 - Proposed Extension of Existing Information Collection; Independent Contractor Registration and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Mine... Contractor Registration and Identification AGENCY: Mine Safety and Health Administration, Labor. ACTION... requirements can be properly assessed. The Mine Safety and Health Administration is soliciting...

  17. Rac regulation of transformation, gene expression, and actin organization by multiple, PAK-independent pathways.

    PubMed Central

    Westwick, J K; Lambert, Q T; Clark, G J; Symons, M; Van Aelst, L; Pestell, R G; Der, C J

    1997-01-01

    Rac1 and RhoA are members of the Rho family of Ras-related proteins and function as regulators of actin cytoskeletal organization, gene expression, and cell cycle progression. Constitutive activation of Rac1 and RhoA causes tumorigenic transformation of NIH 3T3 cells, and their functions may be required for full Ras transformation. The effectors by which Rac1 and RhoA mediate these diverse activities, as well as the interrelationship between these events, remain poorly understood. Rac1 is distinct from RhoA in its ability to bind and activate the p65 PAK serine/threonine kinase, to induce lamellipodia and membrane ruffling, and to activate the c-Jun NH2-terminal kinase (JNK). To assess the role of PAK in Rac1 function, we identified effector domain mutants of Rac1 and Rac1-RhoA chimeric proteins that no longer bound PAK. Surprisingly, PAK binding was dispensable for Rac1-induced transformation and lamellipodium formation, as well as activation of JNK, p38, and serum response factor (SRF). However, the ability of Rac1 to bind to and activate PAK correlated with its ability to stimulate transcription from the cyclin D1 promoter. Furthermore, Rac1 activation of JNK or SRF, or induction of lamellipodia, was neither necessary nor sufficient for Rac1 transforming activity. Finally, the signaling pathways that mediate Rac1 activation of SRF or JNK were distinct from those that mediate Rac1 induction of lamellipodia. Taken together, these observations suggest that Rac1 regulates at least four distinct effector-mediated functions and that multiple pathways may contribute to Rac1-induced cellular transformation. PMID:9032259

  18. Audit of health benefit costs at the Department`s Management and Operating Contractors

    SciTech Connect

    Not Available

    1994-06-23

    The audit disclosed that the Department and certain of its contractors had initiated several positive actions to contain health benefit costs: improving data collection, increasing training, reviewing changes to health plans, improving the language in one contract, increasing the employees, share of health costs at one contractor, and initiating self-insurance at another contractor. Despite these actions, further improvements are needed in the administration of the contractor employee health benefit plans. It was found that the Department did not have the policies and procedures necessary to ensure that the health benefit costs met the tests for reasonableness. The audit of $95 million in health benefit costs incurred at six Management and Operating contractors showed that $15.4 million of these costs were excessive compared to national norms.

  19. Employee and independent contractor relationships.

    PubMed

    Wren, K R; Wren, T L; Monti, E J; Turco, S J

    1999-05-01

    Most practitioners find themselves at a disadvantage in dealing with business issues and relationships. As health care continues to change, knowledge of contracts and business relationships will help CRNA practitioners navigate new as well as traditional practice settings. This article discusses the advantages and disadvantages of two business relationships: employee and independent contractor. PMID:10504911

  20. 76 FR 51344 - Butte County Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ...The Butte County Resource Advisory Committee (RAC) will hold a meeting on August 29, 2011 in Oroville, CA. The purpose of the meeting is to review Cycle 2 project applications for potential funding recommendations to Lassen, Plumas or Mendocino National Forest Supervisors. The funding is made available under Title II provisions of the Secure Rural Schools and Community Self-Determination Act......

  1. Exome sequencing identifies recurrent somatic RAC1 mutations in melanoma

    SciTech Connect

    Krauthammer, Michael; Kong, Yong; Ha, Byung Hak; Evans, Perry; Bacchiocchi, Antonella; McCusker, James P.; Cheng, Elaine; Davis, Matthew J.; Goh, Gerald; Choi, Murim; Ariyan, Stephan; Narayan, Deepak; Dutton-Regester, Ken; Capatana, Ana; Holman, Edna C.; Bosenberg, Marcus; Sznol, Mario; Kluger, Harriet M.; Brash, Douglas E.; Stern, David F.; Materin, Miguel A.; Lo, Roger S.; Mane, Shrikant; Ma, Shuangge; Kidd, Kenneth K.; Hayward, Nicholas K.; Lifton, Richard P.; Schlessinger, Joseph; Boggon, Titus J.; Halaban, Ruth

    2012-10-11

    We characterized the mutational landscape of melanoma, the form of skin cancer with the highest mortality rate, by sequencing the exomes of 147 melanomas. Sun-exposed melanomas had markedly more ultraviolet (UV)-like C>T somatic mutations compared to sun-shielded acral, mucosal and uveal melanomas. Among the newly identified cancer genes was PPP6C, encoding a serine/threonine phosphatase, which harbored mutations that clustered in the active site in 12% of sun-exposed melanomas, exclusively in tumors with mutations in BRAF or NRAS. Notably, we identified a recurrent UV-signature, an activating mutation in RAC1 in 9.2% of sun-exposed melanomas. This activating mutation, the third most frequent in our cohort of sun-exposed melanoma after those of BRAF and NRAS, changes Pro29 to serine (RAC1{sup P29S}) in the highly conserved switch I domain. Crystal structures, and biochemical and functional studies of RAC1{sup P29S} showed that the alteration releases the conformational restraint conferred by the conserved proline, causes an increased binding of the protein to downstream effectors, and promotes melanocyte proliferation and migration. These findings raise the possibility that pharmacological inhibition of downstream effectors of RAC1 signaling could be of therapeutic benefit.

  2. 75 FR 12723 - Plumas County Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-17

    ... agency #0;statements of organization and functions are examples of documents #0;appearing in this section...; ] DEPARTMENT OF AGRICULTURE Forest Service Plumas County Resource Advisory Committee (RAC) AGENCY: Forest... for Cycle 10 funding and select projects to be recommended to the Plumas National Forest...

  3. 75 FR 21220 - Del Norte Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ... agency #0;statements of organization and functions are examples of documents #0;appearing in this section...; ] DEPARTMENT OF AGRICULTURE Forest Service Del Norte Resource Advisory Committee (RAC) AGENCY: Forest Service... Rivers National Forest, 1330 Bayshore Way, Eureka, CA 95503 (707) 441-3673; e-mail...

  4. 77 FR 64099 - Snohomish County Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-18

    ... (360) 436-2301, email pforbes@fs.fed.us . Individuals who use telecommunication devices for the deaf.... More information will be posted on the Mt. Baker-Snoqualmie National Forest Web site at http://www.fs.fed.us/r6/mbs/projects/rac.shtml . Comments may be sent via email to pforbes@fs.fed.us or...

  5. 75 FR 36061 - Humboldt Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-24

    ... Rivers National Forest Office, 1330 Bayshore Way, Eureka, CA 95501. FOR FURTHER INFORMATION CONTACT: Julie Ranieri, Committee Coordinator, Six Rivers National Forest, 1330 Bayshore Way, Eureka, CA 95503... meeting. SUMMARY: The Humboldt Resource Advisory Committee (RAC) will meet in Eureka, California....

  6. 75 FR 27703 - Humboldt Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-18

    ... Rivers National Forest Office, 1330 Bayshore Way, Eureka, CA 95501. FOR FURTHER INFORMATION CONTACT: Julie Ranieri, Committee Coordinator, Six Rivers National Forest, 1330 Bayshore Way, Eureka, CA 95503... meeting. SUMMARY: The Humboldt Resource Advisory Committee (RAC) will meet in Eureka, California....

  7. Debates, divisions, and decisions: recombinant DNA advisory committee (RAC) authorization of the first human gene transfer experiments.

    PubMed Central

    Carmen, I H

    1992-01-01

    Possibly the most far-reaching, controversial research currently being conducted in the international biological science community involves human gene therapy experimentation. In this paper, I report the dynamics of the political process which ultimately found the Recombinant DNA Advisory Committee (RAC) of the National Institutes of Health approving for the first time protocols of this genre. A full appreciation of the policy-making dialogue shows that significant participants perceived the process from very different vantage points regarding the way in which the American political system works and the way in which it ought to work. I argue that, if we are to understand how the RAC should proceed in orchestrating a human gene therapy policy agenda, then we must flesh out and critically analyze these competing vantage points. To that end, I postulate seven possible "action models" for characterizing how protocol assessments of the type at issue might be developed given the nature of our politics, reaching the conclusion that one of these models holds out the most promise for synthesizing efficaciously the key factors involved. In conclusion, I discuss how the RAC might profitably employ this preferred strategy in these and other cases. PMID:1734711

  8. Integration of the Rac1- and actin-binding properties of Coronin-1C

    PubMed Central

    Tilley, Frances C; Williamson, Rosalind C; Race, Paul R; Rendall, Thomas C; Bass, Mark D

    2015-01-01

    The coronin family of actin-binding proteins regulate actin branching by inhibiting Arp2/3. We recently reported 2 interactions that were unique to coronin-1C: binding of a Rac1 inhibitor, RCC2, to the unique linker region and Rac1 itself to the propeller domain in a manner that differs from that proposed for other coronins. Through these interactions coronin-1C redistributes Rac1 from the back of the cell to the leading edge for either activation or sequestration by the associated Rac1-inhibitor, RCC2. Here we investigate the relationship between the Rac1- and actin-binding properties of coronin-1C and find that, although actin appears to be involved in the retrafficking of Rac1, signaling by Rac1 lies upstream of the stress fiber-formation, for which the coronins were originally characterized. PMID:25862165

  9. Caspase 3-Mediated Inactivation of Rac GTPases Promotes Drug-Induced Apoptosis in Human Lymphoma Cells

    PubMed Central

    Zhang, Baolin; Zhang, Yaqin; Shacter, Emily

    2003-01-01

    The Rac members of the Rho family GTPases control signaling pathways that regulate diverse cellular activities, including cytoskeletal organization, gene transcription, and cell transformation. Rac is implicated in apoptosis, but little is known about the mechanism by which it responds to apoptotic stimuli. Here we demonstrate that endogenous Rac GTPases are caspase 3 substrates that are cleaved in human lymphoma cells during drug-induced apoptosis. Cleavage of Rac1 occurs at two unconventional caspase 3 sites, VVGD11/G and VMVD47/G, and results in inactivation of the GTPase and effector functions of the protein (binding to the p21-activated protein kinase PAK1). Expression of caspase 3-resistant Rac1 mutants in the cells suppresses drug-induced apoptosis. Thus, proteolytic inactivation of Rac GTPases represents a novel, irreversible mechanism of Rac downregulation that allows maximal cell death following drug treatment. PMID:12897143

  10. Rac1 promotes diethylnitrosamine (DEN)-induced formation of liver tumors.

    PubMed

    Bopp, Anita; Wartlick, Friedrich; Henninger, Christian; Schwarz, Michael; Kaina, Bernd; Fritz, Gerhard

    2015-03-01

    To elucidate the function of the Ras-homologous GTPase Rac1 in hepatocarcinogenesis induced by diethylnitrosamine (DEN), mice lacking hepatic Rac1 expression were treated with DEN and compared to the wild-type (WT). Rac1 knock-out (KO) mice were found to have a lower tumor yield as compared to Rac1 proficient mice. The small-sized tumors formed in the absence of Rac1 lack an activated Ras/Raf/mitogen-activated protein kinase pathway, as indicated by the absence of p-ERK expression. Apparently, Rac1 is required for Ras-driven oncogenic pathways. Moreover, tumors in Rac1 deficient mice were glutamine synthase (GS) negative. They displayed a high number of p-H3-positive and cyclinB1 expressing cells, pointing to a defect in mitotic progression. To elucidate the influence of Rac1 on mechanisms of tumor initiation, acute DEN-induced hepatic stress responses were monitored. Rac1 deficiency caused fairly complex, partially time-dependent, alterations in both basal and/or DEN-induced messenger RNA (mRNA) and protein levels of susceptibility-related genes. Basal protein expression of DNA repair factors Brca1 and DNA repair protein RAD51 homolog (Rad51) and the cell cycle regulatory factor p27 was enhanced in the absence of Rac1. Following DEN treatment, p21 mRNA and protein expression was stimulated independent of the Rac1 status. Lack of Rac1 increased mechanisms of the DNA damage response (DDR), as shown by elevated protein levels of p-ATR, p-p53 and γH2AX 24h after DEN treatment. The data show that Rac1 is essential for DEN-stimulated hepatocarcinogenesis. We hypothesize that it promotes tumor initiation by counteracting the elimination of initiated cells and, moreover, alleviates the outgrowth of transformed cells. Hence, pharmacological targeting of Rac1 could be suitable for chemoprevention.

  11. 48 CFR 952.251-70 - Contractor employee travel discounts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... identification signed by the authorized Contracting Officer. (b) Contracted airlines. Contractors are not... Government contractors, the Contractor may review commercial publications such as the Official Airline...

  12. 45 CFR 5b.12 - Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... must contain a provision requiring the contractor to comply with the Act and this part. (b) All... beyond that date. (c) A contractor and any employee of such contractor shall be considered employees of... employee standards of conduct listed in appendix A of this part where the contract contains a...

  13. 32 CFR 310.12 - Government contractors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 2 2013-07-01 2013-07-01 false Government contractors. 310.12 Section 310.12... PROGRAM DOD PRIVACY PROGRAM Systems of Records § 310.12 Government contractors. (a) Applicability to government contractors. (1) When a DoD Component contract requires the operation or maintenance of a...

  14. 32 CFR 310.12 - Government contractors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Government contractors. 310.12 Section 310.12... PROGRAM DOD PRIVACY PROGRAM Systems of Records § 310.12 Government contractors. (a) Applicability to government contractors. (1) When a DoD Component contract requires the operation or maintenance of a...

  15. 32 CFR 310.12 - Government contractors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 2 2011-07-01 2011-07-01 false Government contractors. 310.12 Section 310.12... PROGRAM DOD PRIVACY PROGRAM Systems of Records § 310.12 Government contractors. (a) Applicability to government contractors. (1) When a DoD Component contract requires the operation or maintenance of a...

  16. 32 CFR 310.12 - Government contractors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 2 2012-07-01 2012-07-01 false Government contractors. 310.12 Section 310.12... PROGRAM DOD PRIVACY PROGRAM Systems of Records § 310.12 Government contractors. (a) Applicability to government contractors. (1) When a DoD Component contract requires the operation or maintenance of a...

  17. 32 CFR 310.12 - Government contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Government contractors. 310.12 Section 310.12... PROGRAM DOD PRIVACY PROGRAM Systems of Records § 310.12 Government contractors. (a) Applicability to government contractors. (1) When a DoD Component contract requires the operation or maintenance of a...

  18. Space plasma contractor research, 1988

    NASA Technical Reports Server (NTRS)

    Williams, John D.; Wilbur, Paul J.

    1989-01-01

    Results of experiments conducted on hollow cathode-based plasma contractors are reported. Specific tests in which attempts were made to vary plasma conditions in the simulated ionospheric plasma are described. Experimental results showing the effects of contractor flowrate and ion collecting surface size on contactor performance and contactor plasma plume geometry are presented. In addition to this work, one-dimensional solutions to spherical and cylindircal space-charge limited double-sheath problems are developed. A technique is proposed that can be used to apply these solutions to the problem of current flow through elongated double-sheaths that separate two cold plasmas. Two conference papers which describe the essential features of the plasma contacting process and present data that should facilitate calibration of comprehensive numerical models of the plasma contacting process are also included.

  19. Inhibition of Rac1 GTPase activity affects porcine oocyte maturation and early embryo development

    PubMed Central

    Song, Si-Jing; Wang, Qiao-Chu; Jia, Ru-Xia; Cui, Xiang-Shun; Kim, Nam-Hyung; Sun, Shao-Chen

    2016-01-01

    Mammalian oocyte asymmetric division relies on the eccentric positioning of the spindle, resulting in the polar body formation. Small signaling G protein Rac1 is a member of GTPases, which regulates a diverse array of cellular events, including the control of cell growth, cytoskeletal reorganization, and the activation of protein kinases. However, effects of Rac1 on the porcine oocyte maturation and early embryo development are not fully understood. In present study we investigated the role of Rac1 in oocyte maturation and embryo cleavage. We first found that Rac1 localized at the cortex of the porcine oocytes, and disrupting the Rac1 activities by treating with NSC 23766 led to the failure of polar body emission. In addition, a majority of treated oocytes exhibited abnormal spindle morphology, indicating that Rac1 may involve into porcine oocyte spindle formation. This might be due to the regulation of Rac1 on MAPK, since p-MAPK expression decreased after NSC 23766 treatments. Moreover, we found that the position of most meiotic spindles in treated oocytes were away from the cortex, indicating the roles of Rac1 on meiotic spindle positioning. Our results also showed that inhibition of Rac1 activity caused the failure of early embryo development. Therefore, our study showed the critical roles of Rac1 GTPase on porcine oocyte maturation and early embryo cleavage. PMID:27694954

  20. RAC1 activation drives pathologic interactions between the epidermis and immune cells

    PubMed Central

    Winge, Mårten C.G.; Ohyama, Bungo; Dey, Clara N.; Boxer, Lisa M.; Li, Wei; Ehsani-Chimeh, Nazanin; Truong, Allison K.; Wu, Diane; Armstrong, April W.; Makino, Teruhiko; Davidson, Matthew; Starcevic, Daniela; Nguyen, Ngon T.; Hashimoto, Takashi; Homey, Bernard; Khavari, Paul A.; Bradley, Maria; Waterman, Elizabeth A.; Marinkovich, M. Peter

    2016-01-01

    Interactions between the epidermis and the immune system govern epidermal tissue homeostasis. These epidermis-immune interactions are altered in the inflammatory disease psoriasis; however, the pathways that underlie this aberrant immune response are not well understood. Here, we determined that Ras-related C3 botulinum toxin substrate 1 (RAC1) is a key mediator of epidermal dysfunction. RAC1 activation was consistently elevated in psoriatic epidermis and primary psoriatic human keratinocytes (PHKCs) exposed to psoriasis-related stimuli, but not in skin from patients with basal or squamous cell carcinoma. Expression of a constitutively active form of RAC1 (RACV12) in mice resulted in the development of lesions similar to those of human psoriasis that required the presence of an intact immune system. RAC1V12-expressing mice and human psoriatic skin showed similar RAC1-dependent signaling as well as transcriptional overlap of differentially expressed epidermal and immune pathways. Coculture of PHKCs with immunocytes resulted in the upregulation of RAC1-dependent proinflammatory cytokines, an effect that was reproduced by overexpressing RAC1 in normal human keratinocytes. In keratinocytes, modulating RAC1 activity altered differentiation, proliferation, and inflammatory pathways, including STAT3, NFκB, and zinc finger protein 750 (ZNF750). Finally, RAC1 inhibition in xenografts composed of human PHKCs and immunocytes abolished psoriasiform hyperplasia and inflammation in vivo. These studies implicate RAC1 as a potential therapeutic target for psoriasis and as a key orchestrator of pathologic epidermis-immune interactions. PMID:27294528

  1. A palmitoylation switch mechanism regulates Rac1 function and membrane organization

    PubMed Central

    Navarro-Lérida, Inmaculada; Sánchez-Perales, Sara; Calvo, María; Rentero, Carles; Zheng, Yi; Enrich, Carlos; Del Pozo, Miguel A

    2012-01-01

    The small GTPase Rac1 plays important roles in many processes, including cytoskeletal reorganization, cell migration, cell-cycle progression and gene expression. The initiation of Rac1 signalling requires at least two mechanisms: GTP loading via the guanosine triphosphate (GTP)/guanosine diphosphate (GDP) cycle, and targeting to cholesterol-rich liquid-ordered plasma membrane microdomains. Little is known about the molecular mechanisms governing this specific compartmentalization. We show that Rac1 can incorporate palmitate at cysteine 178 and that this post-translational modification targets Rac1 for stabilization at actin cytoskeleton-linked ordered membrane regions. Palmitoylation of Rac1 requires its prior prenylation and the intact C-terminal polybasic region and is regulated by the triproline-rich motif. Non-palmitoylated Rac1 shows decreased GTP loading and lower association with detergent-resistant (liquid-ordered) membranes (DRMs). Cells expressing no Rac1 or a palmitoylation-deficient mutant have an increased content of disordered membrane domains, and markers of ordered membranes isolated from Rac1-deficient cells do not correctly partition in DRMs. Importantly, cells lacking Rac1 palmitoylation show spreading and migration defects. These data identify palmitoylation as a mechanism for Rac1 function in actin cytoskeleton remodelling by controlling its membrane partitioning, which in turn regulates membrane organization. PMID:22157745

  2. ROLE OF RAC-1 DEPENDENT NADPH OXIDASE IN THE GROWTH OF PANCREATIC CANCER

    PubMed Central

    Du, Juan; Liu, Jingru; Smith, Brian J.; Tsao, Ming-Sound; Cullen, Joseph J.

    2010-01-01

    K-ras mutations occur in as high as 95% of patients with pancreatic cancer. K-ras activates Rac1-dependent NADPH oxidase, a key source of superoxide. Superoxide plays an important role in pancreatic cancer cell proliferation and scavenging or decreasing the levels of superoxide inhibits pancreatic cancer cell growth both in vitro and in vivo. DNA microarray analysis and RT-PCR has demonstrated that Rac1 is also upregulated in pancreatic cancer. The aim of this study was to determine if inhibiting Rac1 would alter pancreatic tumor cell behavior. Human pancreatic cancer cells with mutant K-ras (MIA PaCa-2), wild-type K-ras (BxPC-3), and the immortal H6c7 cell line (pancreatic ductal epithelium) expressing K-ras oncogene (H6c7eR-KrasT) that is tumorigenic, were infected with a dominant/negative Rac1 construct (AdN17Rac1). In cells with mutant K-ras, AdN17Rac1 decreased rac activity, decreased superoxide levels, and inhibited in vitro growth. However in the BxPC-3 cell line, AdN17Rac1 did not change rac activity, superoxide levels, or in vitro cell growth. Additionally, AdN17Rac1 decreased superoxide levels and inhibited in vitro growth in the KrasT tumorigenic cell line, but had no effect in the immortalized H6c7 cell line. In human pancreatic tumor xenografts, intratumoral injections of AdN17Rac1 inhibited tumor growth. These results suggest that activation of Rac1-dependent superoxide generation leads to pancreatic cancer cell proliferation. In pancreatic cancer inhibition of Rac1 may be a potential therapeutic target. PMID:21037555

  3. Neuronal filopodium formation induced by the membrane glycoprotein M6a (Gpm6a) is facilitated by coronin-1a, Rac1, and p21-activated kinase 1 (Pak1).

    PubMed

    Alvarez Juliá, Anabel; Frasch, Alberto C; Fuchsova, Beata

    2016-04-01

    Stress-responsive neuronal membrane glycoprotein M6a (Gpm6a) functions in neurite extension, filopodium and spine formation and synaptogenesis. The mechanisms of Gpm6a action in these processes are incompletely understood. Previously, we identified the actin regulator coronin-1a (Coro1a) as a putative Gpm6a interacting partner. Here, we used co-immunoprecipitation assays with the anti-Coro1a antibody to show that Coro1a associates with Gpm6a in rat hippocampal neurons. By immunofluorescence microscopy, we demonstrated that in hippocampal neurons Coro1a localizes in F-actin-enriched regions and some of Coro1a spots co-localize with Gpm6a labeling. Notably, the over-expression of a dominant-negative form of Coro1a as well as its down-regulation by siRNA interfered with Gpm6a-induced filopodium formation. Coro1a is known to regulate the plasma membrane translocation and activation of small GTPase Rac1. We show that Coro1a co-immunoprecipitates with Rac1 together with Gpm6a. Pharmacological inhibition of Rac1 resulted in a significant decrease in filopodium formation by Gpm6a. The same was observed upon the co-expression of Gpm6a with the inactive GDP-bound form of Rac1. In this case, the elevated membrane recruitment of GDP-bound Rac1 was detected as well. Moreover, the kinase activity of the p21-activated kinase 1 (Pak1), a main downstream effector of Rac1 that acts downstream of Coro1a, was required for Gpm6a-induced filopodium formation. Taken together, our results provide evidence that a signaling pathway including Coro1a, Rac1, and Pak1 facilitates Gpm6a-induced filopodium formation. Formation of filopodia by membrane glycoprotein M6a (Gpm6a) requires actin regulator coronin-1a (Coro1a), known to regulate plasma membrane localization and activation of Rac1 and its downstream effector Pak1. Coro1a associates with Gpm6a. Blockage of Coro1a, Rac1, or Pak1 interferes with Gpm6a-induced filopodium formation. Moreover, Gpm6a facilitates Rac1 membrane recruitment

  4. Neuronal filopodium formation induced by the membrane glycoprotein M6a (Gpm6a) is facilitated by coronin-1a, Rac1, and p21-activated kinase 1 (Pak1).

    PubMed

    Alvarez Juliá, Anabel; Frasch, Alberto C; Fuchsova, Beata

    2016-04-01

    Stress-responsive neuronal membrane glycoprotein M6a (Gpm6a) functions in neurite extension, filopodium and spine formation and synaptogenesis. The mechanisms of Gpm6a action in these processes are incompletely understood. Previously, we identified the actin regulator coronin-1a (Coro1a) as a putative Gpm6a interacting partner. Here, we used co-immunoprecipitation assays with the anti-Coro1a antibody to show that Coro1a associates with Gpm6a in rat hippocampal neurons. By immunofluorescence microscopy, we demonstrated that in hippocampal neurons Coro1a localizes in F-actin-enriched regions and some of Coro1a spots co-localize with Gpm6a labeling. Notably, the over-expression of a dominant-negative form of Coro1a as well as its down-regulation by siRNA interfered with Gpm6a-induced filopodium formation. Coro1a is known to regulate the plasma membrane translocation and activation of small GTPase Rac1. We show that Coro1a co-immunoprecipitates with Rac1 together with Gpm6a. Pharmacological inhibition of Rac1 resulted in a significant decrease in filopodium formation by Gpm6a. The same was observed upon the co-expression of Gpm6a with the inactive GDP-bound form of Rac1. In this case, the elevated membrane recruitment of GDP-bound Rac1 was detected as well. Moreover, the kinase activity of the p21-activated kinase 1 (Pak1), a main downstream effector of Rac1 that acts downstream of Coro1a, was required for Gpm6a-induced filopodium formation. Taken together, our results provide evidence that a signaling pathway including Coro1a, Rac1, and Pak1 facilitates Gpm6a-induced filopodium formation. Formation of filopodia by membrane glycoprotein M6a (Gpm6a) requires actin regulator coronin-1a (Coro1a), known to regulate plasma membrane localization and activation of Rac1 and its downstream effector Pak1. Coro1a associates with Gpm6a. Blockage of Coro1a, Rac1, or Pak1 interferes with Gpm6a-induced filopodium formation. Moreover, Gpm6a facilitates Rac1 membrane recruitment

  5. The Truncated Form of Glycoprotein gp2 of Equine Herpesvirus 1 (EHV-1) Vaccine Strain KyA Is Not Functionally Equivalent to Full-Length gp2 Encoded by EHV-1 Wild-Type Strain RacL11

    PubMed Central

    von Einem, Jens; Wellington, Janet; Whalley, J. Millar; Osterrieder, Kerstin; O'Callaghan, Dennis J.; Osterrieder, Nikolaus

    2004-01-01

    Most equine herpesvirus 1 (EHV-1) strains, including the naturally occurring virulent RacL11 isolate, encode a large glycoprotein, gp2 (250 kDa), which is expressed from gene 71. Besides other alterations in the viral genome, the avirulent strain KyA harbors an in-frame deletion of 1,242 nucleotides in gene 71. To examine the contributions of gp2 variation to virus growth and virulence, mutant RacL11 and KyA viruses expressing full-length or truncated gp2 were generated. Western blot analyses demonstrated expression of a 250-kDa gp2 in cells infected with RacL11 virus or a mutant KyA virus harboring full-length gene 71, whereas a 75- to 80-kDa gp2 was detected in cells infected with KyA or mutant RacL11 virus expressing KyA gp2. The RacL11 gp2 precursor of 250 kDa in size and its truncated KyA counterpart of 80 kDa, as well as the 42-kDa carboxy-terminal gp2 subunit, were incorporated into virus particles. Absence of gp2 in RacL11 resulted in a 6-fold reduction of extracellular virus titers and a 13% reduction of plaque diameters, whereas gp2-negative KyA exhibited a 55% reduction in plaque diameter and a 51-fold decrease in extracellular virus titers. The massive growth defects of gp2-negative KyA could be restored by reinsertion of the truncated but not the full-length gp2 gene. The virulence of the generated gp2 mutant viruses was compared to the virulence of KyA and RacL11 in a murine infection model. RacL11 lacking gp2 was apathogenic for BALB/c mice, and insertion of the truncated KyA gp2 gene into RacL11 was unable to restore virulence. Similarly, replacement in the KyA genome of the truncated with the full-length RacL11 gene 71 did not result in the generation of virulent virus. From the results we conclude that full-length and truncated EHV-1 gp2 are not functionally equivalent and cannot compensate for the action of their homologues in allogeneic virus backgrounds. PMID:14990719

  6. The truncated form of glycoprotein gp2 of equine herpesvirus 1 (EHV-1) vaccine strain KyA is not functionally equivalent to full-length gp2 encoded by EHV-1 wild-type strain RacL11.

    PubMed

    von Einem, Jens; Wellington, Janet; Whalley, J Millar; Osterrieder, Kerstin; O'Callaghan, Dennis J; Osterrieder, Nikolaus

    2004-03-01

    Most equine herpesvirus 1 (EHV-1) strains, including the naturally occurring virulent RacL11 isolate, encode a large glycoprotein, gp2 (250 kDa), which is expressed from gene 71. Besides other alterations in the viral genome, the avirulent strain KyA harbors an in-frame deletion of 1,242 nucleotides in gene 71. To examine the contributions of gp2 variation to virus growth and virulence, mutant RacL11 and KyA viruses expressing full-length or truncated gp2 were generated. Western blot analyses demonstrated expression of a 250-kDa gp2 in cells infected with RacL11 virus or a mutant KyA virus harboring full-length gene 71, whereas a 75- to 80-kDa gp2 was detected in cells infected with KyA or mutant RacL11 virus expressing KyA gp2. The RacL11 gp2 precursor of 250 kDa in size and its truncated KyA counterpart of 80 kDa, as well as the 42-kDa carboxy-terminal gp2 subunit, were incorporated into virus particles. Absence of gp2 in RacL11 resulted in a 6-fold reduction of extracellular virus titers and a 13% reduction of plaque diameters, whereas gp2-negative KyA exhibited a 55% reduction in plaque diameter and a 51-fold decrease in extracellular virus titers. The massive growth defects of gp2-negative KyA could be restored by reinsertion of the truncated but not the full-length gp2 gene. The virulence of the generated gp2 mutant viruses was compared to the virulence of KyA and RacL11 in a murine infection model. RacL11 lacking gp2 was apathogenic for BALB/c mice, and insertion of the truncated KyA gp2 gene into RacL11 was unable to restore virulence. Similarly, replacement in the KyA genome of the truncated with the full-length RacL11 gene 71 did not result in the generation of virulent virus. From the results we conclude that full-length and truncated EHV-1 gp2 are not functionally equivalent and cannot compensate for the action of their homologues in allogeneic virus backgrounds.

  7. 48 CFR 1009.204-70 - Contractor publicity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Contractor publicity. 1009... ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Qualifications Requirements 1009.204-70 Contractor publicity... Contractor Publicity in all solicitations and contracts....

  8. Ubiquitination of Rac1 by inhibitors of apoptosis (IAPs).

    PubMed

    Oberoi-Khanuja, Tripat Kaur; Rajalingam, Krishnaraj

    2014-01-01

    Ubiquitination of proteins has emerged as a vital posttranslational modification at the crux of numerous signalling pathways, regulating them in various ways. Most members of the small GTPase family including Ras and Rho proteins are regulated by GEFs, GAPs, and RhoGDIs that modulate their cycling between the active and inactive states. Ubiquitination has added another layer to the regulation of small GTPases. Recently, we have uncovered that inhibitors of apoptosis (IAPs) function as direct E3 ubiquitin ligases for Rho GTPase Rac1 and target it for proteasomal degradation. Here, we describe in vitro and in vivo ubiquitination assays for detecting the conjugation of ubiquitin to Rac1 by XIAP and cIAP1.

  9. IAPs as E3 ligases of Rac1: shaping the move.

    PubMed

    Oberoi-Khanuja, Tripat Kaur; Rajalingam, Krishnaraj

    2012-01-01

    Inhibitors of Apoptosis Proteins (IAPs) are well-studied E3 ubiquitin ligases predominantly known for regulation of apoptosis. We uncovered that IAPs can function as a direct E3 ubiquitin ligase of RhoGTPase Rac1. cIAP1 and XIAP directly conjugate polyubiquitin chains to Lysine 147 of activated Rac1 and target it for proteasomal degradation. Consistently, loss of these IAPs by various strategies led to stabilization of Rac1 and mesenchymal mode of migration in tumor cells. IAPs also regulate Rac1 degradation upon RhoGDI1 depletion and CNF1 toxin treatment. Our observations revealed an evolutionarily conserved role of IAPs in regulating Rac1 stability shedding light on to the mechanisms behind ubiquitination-dependent inactivation of Rac1 signaling.

  10. Activated Rac1 requires gp130 for Stat3 activation, cell proliferation and migration

    SciTech Connect

    Arulanandam, Rozanne; Geletu, Mulu; Feracci, Helene; Raptis, Leda

    2010-03-10

    Rac1 (Rac) is a member of the Rho family of small GTPases which controls cell migration by regulating the organization of actin filaments. Previous results suggested that mutationally activated forms of the Rho GTPases can activate the Signal Transducer and Activator of Transcription-3 (Stat3), but the exact mechanism is a matter of controversy. We recently demonstrated that Stat3 activity of cultured cells increases dramatically following E-cadherin engagement. To better understand this pathway, we now compared Stat3 activity levels in mouse HC11 cells before and after expression of the mutationally activated Rac1 (Rac{sup V12}), at different cell densities. The results revealed for the first time a dramatic increase in protein levels and activity of both the endogenous Rac and Rac{sup V12} with cell density, which was due to inhibition of proteasomal degradation. In addition, Rac{sup V12}-expressing cells had higher Stat3, tyrosine-705 phosphorylation and activity levels at all densities, indicating that Rac{sup V12} is able to activate Stat3. Further examination of the mechanism of Stat3 activation showed that Rac{sup V12} expression caused a surge in mRNA of Interleukin-6 (IL6) family cytokines, known potent Stat3 activators. Knockdown of gp130, the common subunit of this family reduced Stat3 activity, indicating that these cytokines may be responsible for the Stat3 activation by Rac{sup V12}. The upregulation of IL6 family cytokines was required for cell migration and proliferation induced by Rac{sup V12}, as shown by gp130 knockdown experiments, thus demonstrating that the gp130/Stat3 axis represents an essential effector of activated Rac for the regulation of key cellular functions.

  11. 45 CFR 30.14 - Contracting with private collection contractors and with entities that locate and recover...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... collection action, and refer debts to Justice for litigation; (2) The private collection contractor is not... Treasury for debt collection under 31 U.S.C. 3711(g) and 31 CFR 285.12(e). (c) Debts arising under the Social Security Act (which can be collected by private collection contractors only by Treasury after...

  12. 45 CFR 30.14 - Contracting with private collection contractors and with entities that locate and recover...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... collection action, and refer debts to Justice for litigation; (2) The private collection contractor is not... Treasury for debt collection under 31 U.S.C. 3711(g) and 31 CFR 285.12(e). (c) Debts arising under the Social Security Act (which can be collected by private collection contractors only by Treasury after...

  13. Melatonin suppresses hypoxia-induced migration of HUVECs via inhibition of ERK/Rac1 activation.

    PubMed

    Yang, Ling; Zheng, Jianchao; Xu, Rui; Zhang, Yujie; Gu, Luo; Dong, Jing; Zhu, Yichao; Zhou, Ruijue; Zheng, Lu; Zhang, Xiaoying; Du, Jun

    2014-01-01

    Melatonin, a naturally-occurring hormone, possesses antioxidant properties and ameliorates vascular endothelial dysfunction. In this study, we evaluate the impact of melatonin on the migratory capability of human umbilical vein endothelial cells (HUVECs) to hypoxia and further investigate whether ERK/Rac1 signaling is involved in this process. Here, we found that melatonin inhibited hypoxia-stimulated hypoxia-inducible factor-1α (HIF-1α) expression and cell migration in a dose-dependent manner. Mechanistically, melatonin inhibited Rac1 activation and suppressed the co-localized Rac1 and F-actin on the membrane of HUVECs under hypoxic condition. In addition, the blockade of Rac1 activation with ectopic expression of an inactive mutant form of Rac1-T17N suppressed HIF-1α expression and cell migration in response to hypoxia, as well, but constitutive activation of Rac1 mutant Rac1-V12 restored HIF-1α expression, preventing the inhibition of melatonin on cell migration. Furthermore, the anti-Rac1 effect of melatonin in HUVECs appeared to be associated with its inhibition of ERK phosphorylation, but not that of the PI3k/Akt signaling pathway. Taken together, our work indicates that melatonin exerts an anti-migratory effect on hypoxic HUVECs by blocking ERK/Rac1 activation and subsequent HIF-1α upregulation. PMID:25123138

  14. Extending the Impact of RAC1b Overexpression to Follicular Thyroid Carcinomas

    PubMed Central

    Faria, Márcia; Capinha, Liliana; Simões-Pereira, Joana; Bugalho, Maria João; Silva, Ana Luísa

    2016-01-01

    RAC1b is a hyperactive variant of the small GTPase RAC1 known to be a relevant molecular player in different cancers. Previous studies from our group lead to the evidence that its overexpression in papillary thyroid carcinoma (PTC) is associated with an unfavorable prognosis. In the present study, we intended to extend the analysis of RAC1b expression to thyroid follicular neoplasms and to seek for clinical correlations. RAC1b expression levels were determined by RT-qPCR in thyroid follicular tumor samples comprising 23 follicular thyroid carcinomas (FTCs) and 33 follicular thyroid adenomas (FTAs). RAC1b was found to be overexpressed in 33% of carcinomas while no RAC1b overexpression was documented among follicular adenomas. Patients with a diagnosis of FTC were divided into two groups based on longitudinal evolution and final outcome. RAC1b overexpression was significantly associated with both the presence of distant metastases (P = 0.01) and poorer clinical outcome (P = 0.01) suggesting that, similarly to that previously found in PTCs, RAC1b overexpression in FTCs is also associated with worse outcomes. Furthermore, the absence of RAC1b overexpression in follicular adenomas hints its potential as a molecular marker likely to contribute, in conjunction with other putative markers, to the preoperative differential diagnosis of thyroid follicular lesions. PMID:27127508

  15. Extending the Impact of RAC1b Overexpression to Follicular Thyroid Carcinomas.

    PubMed

    Faria, Márcia; Capinha, Liliana; Simões-Pereira, Joana; Bugalho, Maria João; Silva, Ana Luísa

    2016-01-01

    RAC1b is a hyperactive variant of the small GTPase RAC1 known to be a relevant molecular player in different cancers. Previous studies from our group lead to the evidence that its overexpression in papillary thyroid carcinoma (PTC) is associated with an unfavorable prognosis. In the present study, we intended to extend the analysis of RAC1b expression to thyroid follicular neoplasms and to seek for clinical correlations. RAC1b expression levels were determined by RT-qPCR in thyroid follicular tumor samples comprising 23 follicular thyroid carcinomas (FTCs) and 33 follicular thyroid adenomas (FTAs). RAC1b was found to be overexpressed in 33% of carcinomas while no RAC1b overexpression was documented among follicular adenomas. Patients with a diagnosis of FTC were divided into two groups based on longitudinal evolution and final outcome. RAC1b overexpression was significantly associated with both the presence of distant metastases (P = 0.01) and poorer clinical outcome (P = 0.01) suggesting that, similarly to that previously found in PTCs, RAC1b overexpression in FTCs is also associated with worse outcomes. Furthermore, the absence of RAC1b overexpression in follicular adenomas hints its potential as a molecular marker likely to contribute, in conjunction with other putative markers, to the preoperative differential diagnosis of thyroid follicular lesions. PMID:27127508

  16. Rac1 signaling regulates neutrophil-dependent tissue damage in experimental colitis.

    PubMed

    Yu, Changhui; Zhang, Su; Song, Lei; Wang, Yusheng; Hwaiz, Rundk; Luo, Lingtao; Thorlacius, Henrik

    2014-10-15

    Excessive neutrophil recruitment in the colon is a major feature in acute colitis although the signaling mechanisms behind colonic recruitment of neutrophils remain elusive. Herein, we hypothesized that Rac1 activity might play an important role in neutrophil infiltration in the inflamed colon. Female Balb/c mice were treated with the Rac1 inhibitor NSC23766 (0.5 and 5mg/kg) before and daily after administration of 5% dextran sodium sulfate (DSS). Colonic tissue was collected for quantification of neutrophil recruitment, interleukin-6 (IL-6) and CXC chemokine formation as well as histological damage score five days after challenge with DSS. Rac1 activity was determined by western blot and Mac-1 expression by flow cytometry in neutrophils. Administration of NSC23766 decreased DSS-induced neutrophil recruitment and tissue damage in the colon. Rac1 inhibition decreased colonic formation of IL-6 and CXC chemokines in experimental colitis. Chemokine challenge increased Rac1 activity in neutrophils and NSC23766 markedly reduced this neutrophil activity of Rac1. Inhibition of Rac1 abolished CXC chemokine-induced neutrophil chemotaxis and up-regulation of Mac-1 in vitro. Taken together, Rac1 signaling plays a significant role in controlling accumulation of neutrophils and tissue injury in experimental colitis. Thus, our novel results suggest that targeting Rac1 signaling might be a useful way to protect against neutrophil-mediated tissue injury in acute colitis.

  17. National radon contractor proficiency program. Proficiency report

    SciTech Connect

    Not Available

    1991-02-01

    The report lists those individual contractors who have met the requirements of the Radon Contractor Proficiency (PCP) Program as of December 15, 1990. These requirements are designed to provide minimum proficiency criteria for individuals who design and supervise the installation of radon mitigation systems in buildings. The RCP Program measures the proficiency of an individual contractor, not their company. The report provides the program requirements, RCP mitigation guidelines, State Radon contacts, and information on how to use the RCP tables.

  18. Will RAC change RCM? Hospital leaders are gearing up for the potential of RAC audits to impact the revenue cycle management process.

    PubMed

    Wagner, Steven K

    2010-05-01

    Hospital leaders making headway in anticipating the potential impact of possible RAC audits under the Medicare program are examining their revenue cycle management programs and making those RCM programs more rigorous and specific. Hospitals with experience in the early federal RAC audit demonstration project have accumulated numerous learnings from their participation in the early demo project. One clear learning has been the significant financial impact of going through a RAC audit. CIOs will need to work closely and productively with CFOs, health information management professionals, and others, in order to drill down to the levels at which revenue cycle management programs needto be examined in order to strengthen their effectiveness.

  19. Nectin-4 mutations causing ectodermal dysplasia with syndactyly perturb the rac1 pathway and the kinetics of adherens junction formation.

    PubMed

    Fortugno, Paola; Josselin, Emmanuelle; Tsiakas, Konstantinos; Agolini, Emanuele; Cestra, Gianluca; Teson, Massimo; Santer, René; Castiglia, Daniele; Novelli, Giuseppe; Dallapiccola, Bruno; Kurth, Ingo; Lopez, Marc; Zambruno, Giovanna; Brancati, Francesco

    2014-08-01

    Defective nectin-1 and -4 have been implicated in ectodermal dysplasia (ED) syndromes with variably associated features including orofacial and limb defects. In particular, nectin-1 mutations cause cleft lip/palate ED (CLPED1; OMIM#225060), whereas defective nectin-4 is associated with ED-syndactyly syndrome (EDSS1; OMIM#613573). Although the broad phenotypic overlap suggests a common mode of action of nectin-1 and -4, little is known about the pathogenic mechanisms involved. We report the identification of, to our knowledge, a previously undescribed nectin-4 homozygous p.Val242Met missense mutation in a patient with EDSS1. We used patient skin biopsy and primary keratinocytes, as well as nectin-4 ectopic expression in epithelial cell lines, to characterize functional consequences of p.Val242Met and p.Thr185Met mutations, the latter previously identified in compound heterozygosity with a truncating mutation. We show that nectin-4-altered expression perturbs nectin-1 clustering at keratinocyte contact sites and delays, but does not impede cell-cell aggregation and cadherin recruitment at adherens junctions (AJs). Moreover, trans-interaction of nectin-1 and -4 induces the activation of Rac1, a member of the Rho family of small GTPases, and regulates E-cadherin-mediated cell-cell adhesion. These data outline a synergistic action of nectin-1 and -4 in the early steps of AJ formation and implicate this interaction in modulating the Rac1 signaling pathway.

  20. Functional characterization and cellular dynamics of the CDC-42 - RAC - CDC-24 module in Neurospora crassa.

    PubMed

    Araujo-Palomares, Cynthia L; Richthammer, Corinna; Seiler, Stephan; Castro-Longoria, Ernestina

    2011-01-01

    Rho-type GTPases are key regulators that control eukaryotic cell polarity, but their role in fungal morphogenesis is only beginning to emerge. In this study, we investigate the role of the CDC-42 - RAC - CDC-24 module in Neurospora crassa. rac and cdc-42 deletion mutants are viable, but generate highly compact colonies with severe morphological defects. Double mutants carrying conditional and loss of function alleles of rac and cdc-42 are lethal, indicating that both GTPases share at least one common essential function. The defects of the GTPase mutants are phenocopied by deletion and conditional alleles of the guanine exchange factor (GEF) cdc-24, and in vitro GDP-GTP exchange assays identify CDC-24 as specific GEF for both CDC-42 and RAC. In vivo confocal microscopy shows that this module is organized as membrane-associated cap that covers the hyphal apex. However, the specific localization patterns of the three proteins are distinct, indicating different functions of RAC and CDC-42 within the hyphal tip. CDC-42 localized as confined apical membrane-associated crescent, while RAC labeled a membrane-associated ring excluding the region labeled by CDC42. The GEF CDC-24 occupied a strategic position, localizing as broad apical membrane-associated crescent and in the apical cytosol excluding the Spitzenkörper. RAC and CDC-42 also display distinct localization patterns during branch initiation and germ tube formation, with CDC-42 accumulating at the plasma membrane before RAC. Together with the distinct cellular defects of rac and cdc-42 mutants, these localizations suggest that CDC-42 is more important for polarity establishment, while the primary function of RAC may be maintaining polarity. In summary, this study identifies CDC-24 as essential regulator for RAC and CDC-42 that have common and distinct functions during polarity establishment and maintenance of cell polarity in N. crassa.

  1. New insights into the dimerization of small GTPase Rac/ROP guanine nucleotide exchange factors in rice

    PubMed Central

    Akamatsu, Akira; Uno, Kazumi; Kato, Midori; Wong, Hann Ling; Shimamoto, Ko; Kawano, Yoji

    2015-01-01

    Molecular links between receptor-kinases and Rac/ROP family small GTPases mediated by activator guanine nucleotide exchange factors (GEFs) govern diverse biological processes. However, it is unclear how the Rac/ROP GTPases orchestrate such a wide variety of activities. Here, we show that rice OsRacGEF1 forms homodimers, and heterodimers with OsRacGEF2, at the plasma membrane (PM) and the endoplasmic reticulum (ER). OsRacGEF2 does not bind directly to the receptor-like kinase (RLK) OsCERK1, but forms a complex with OsCERK1 through OsRacGEF1 at the ER. This complex is transported from ER to the PM and there associates with OsRac1, resulting in the formation of a stable immune complex. Such RLK-GEF heterodimer complexes may explain the diversity of Rac/ROP family GTPase signalings. PMID:26251883

  2. Phosphorylation of Threonine 794 on Tie1 by Rac1/PAK1 Reveals a Novel Angiogenesis Regulatory Pathway

    PubMed Central

    Reinardy, Jessica L.; Corey, Daniel M.; Golzio, Christelle; Mueller, Sarah B.; Katsanis, Nicholas; Kontos, Christopher D.

    2015-01-01

    The endothelial receptor tyrosine kinase (RTK) Tie1 was discovered over 20 years ago, yet its precise function and mode of action remain enigmatic. To shed light on Tie1’s role in endothelial cell biology, we investigated a potential threonine phosphorylation site within the juxtamembrane domain of Tie1. Expression of a non-phosphorylatable mutant of this site (T794A) in zebrafish (Danio rerio) significantly disrupted vascular development, resulting in fish with stunted and poorly branched intersomitic vessels. Similarly, T794A-expressing human umbilical vein endothelial cells formed significantly shorter tubes with fewer branches in three-dimensional Matrigel cultures. However, mutation of T794 did not alter Tie1 or Tie2 tyrosine phosphorylation or downstream signaling in any detectable way, suggesting that T794 phosphorylation may regulate a Tie1 function independent of its RTK properties. Although T794 is within a consensus Akt phosphorylation site, we were unable to identify a physiological activator of Akt that could induce T794 phosphorylation, suggesting that Akt is not the physiological Tie1-T794 kinase. However, the small GTPase Ras-related C3 botulinum toxin substrate 1 (Rac1), which is required for angiogenesis and capillary morphogenesis, was found to associate with phospho-T794 but not the non-phosphorylatable T794A mutant. Pharmacological activation of Rac1 induced downstream activation of p21-activated kinase (PAK1) and T794 phosphorylation in vitro, and inhibition of PAK1 abrogated T794 phosphorylation. Our results provide the first demonstration of a signaling pathway mediated by Tie1 in endothelial cells, and they suggest that a novel feedback loop involving Rac1/PAK1 mediated phosphorylation of Tie1 on T794 is required for proper angiogenesis. PMID:26436659

  3. MYADM regulates Rac1 targeting to ordered membranes required for cell spreading and migration.

    PubMed

    Aranda, Juan F; Reglero-Real, Natalia; Kremer, Leonor; Marcos-Ramiro, Beatriz; Ruiz-Sáenz, Ana; Calvo, María; Enrich, Carlos; Correas, Isabel; Millán, Jaime; Alonso, Miguel A

    2011-04-15

    Membrane organization into condensed domains or rafts provides molecular platforms for selective recruitment of proteins. Cell migration is a general process that requires spatiotemporal targeting of Rac1 to membrane rafts. The protein machinery responsible for making rafts competent to recruit Rac1 remains elusive. Some members of the MAL family of proteins are involved in specialized processes dependent on this type of membrane. Because condensed membrane domains are a general feature of the plasma membrane of all mammalian cells, we hypothesized that MAL family members with ubiquitous expression and plasma membrane distribution could be involved in the organization of membranes for cell migration. We show that myeloid-associated differentiation marker (MYADM), a protein with unique features within the MAL family, colocalizes with Rac1 in membrane protrusions at the cell surface and distributes in condensed membranes. MYADM knockdown (KD) cells had altered membrane condensation and showed deficient incorporation of Rac1 to membrane raft fractions and, similar to Rac1 KD cells, exhibited reduced cell spreading and migration. Results of rescue-of-function experiments by expression of MYADM or active Rac1L61 in cells knocked down for Rac1 or MYADM, respectively, are consistent with the idea that MYADM and Rac1 act on parallel pathways that lead to similar functional outcomes. PMID:21325632

  4. Rac1 is a novel regulator of contraction-stimulated glucose uptake in skeletal muscle.

    PubMed

    Sylow, Lykke; Jensen, Thomas E; Kleinert, Maximilian; Mouatt, Joshua R; Maarbjerg, Stine J; Jeppesen, Jacob; Prats, Clara; Chiu, Tim T; Boguslavsky, Shlomit; Klip, Amira; Schjerling, Peter; Richter, Erik A

    2013-04-01

    In skeletal muscle, the actin cytoskeleton-regulating GTPase, Rac1, is necessary for insulin-dependent GLUT4 translocation. Muscle contraction increases glucose transport and represents an alternative signaling pathway to insulin. Whether Rac1 is activated by muscle contraction and regulates contraction-induced glucose uptake is unknown. Therefore, we studied the effects of in vivo exercise and ex vivo muscle contractions on Rac1 signaling and its regulatory role in glucose uptake in mice and humans. Muscle Rac1-GTP binding was increased after exercise in mice (~60-100%) and humans (~40%), and this activation was AMP-activated protein kinase independent. Rac1 inhibition reduced contraction-stimulated glucose uptake in mouse muscle by 55% in soleus and by 20-58% in extensor digitorum longus (EDL; P < 0.01). In agreement, the contraction-stimulated increment in glucose uptake was decreased by 27% (P = 0.1) and 40% (P < 0.05) in soleus and EDL muscles, respectively, of muscle-specific inducible Rac1 knockout mice. Furthermore, depolymerization of the actin cytoskeleton decreased contraction-stimulated glucose uptake by 100% and 62% (P < 0.01) in soleus and EDL muscles, respectively. These are the first data to show that Rac1 is activated during muscle contraction in murine and human skeletal muscle and suggest that Rac1 and possibly the actin cytoskeleton are novel regulators of contraction-stimulated glucose uptake.

  5. Genetic structure and evolution of RAC-GTPases in Arabidopsis thaliana.

    PubMed Central

    Winge, P; Brembu, T; Kristensen, R; Bones, A M

    2000-01-01

    Rho GTPases regulate a number of important cellular functions in eukaryotes, such as organization of the cytoskeleton, stress-induced signal transduction, cell death, cell growth, and differentiation. We have conducted an extensive screening, characterization, and analysis of genes belonging to the Ras superfamily of GTPases in land plants (embryophyta) and found that the Rho family is composed mainly of proteins with homology to RAC-like proteins in terrestrial plants. Here we present the genomic and cDNA sequences of the RAC gene family from the plant Arabidopsis thaliana. On the basis of amino acid alignments and genomic structure comparison of the corresponding genes, the 11 encoded AtRAC proteins can be divided into two distinct groups of which one group apparently has evolved only in vascular plants. Our phylogenetic analysis suggests that the plant RAC genes underwent a rapid evolution and diversification prior to the emergence of the embryophyta, creating a group that is distinct from rac/cdc42 genes in other eukaryotes. In embryophyta, RAC genes have later undergone an expansion through numerous large gene duplications. Five of these RAC duplications in Arabidopsis thaliana are reported here. We also present an hypothesis suggesting that the characteristic RAC proteins in higher plants have evolved to compensate the loss of RAS proteins. PMID:11102387

  6. 44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Under 44 CFR part 351, the role of a RAC is to assist State and local government officials to develop.... (b) Prior to a determination under subpart A (44 CFR 352.6(d)) that Federal facilities and resources... under subpart A (44 CFR 352.6(d)) that Federal facilities and resources are needed, the RAC will...

  7. 44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Under 44 CFR part 351, the role of a RAC is to assist State and local government officials to develop.... (b) Prior to a determination under subpart A (44 CFR 352.6(d)) that Federal facilities and resources... under subpart A (44 CFR 352.6(d)) that Federal facilities and resources are needed, the RAC will...

  8. IAPs regulate the plasticity of cell migration by directly targeting Rac1 for degradation.

    PubMed

    Oberoi, Tripat Kaur; Dogan, Taner; Hocking, Jennifer C; Scholz, Rolf-Peter; Mooz, Juliane; Anderson, Carrie L; Karreman, Christiaan; Meyer zu Heringdorf, Dagmar; Schmidt, Gudula; Ruonala, Mika; Namikawa, Kazuhiko; Harms, Gregory S; Carpy, Alejandro; Macek, Boris; Köster, Reinhard W; Rajalingam, Krishnaraj

    2012-01-01

    Inhibitors of apoptosis proteins (IAPs) are a highly conserved class of multifunctional proteins. Rac1 is a well-studied Rho GTPase that controls numerous basic cellular processes. While the regulation of nucleotide binding to Rac1 is well understood, the molecular mechanisms controlling Rac1 degradation are not known. Here, we demonstrate X-linked IAP (XIAP) and cellular IAP1 (c-IAP1) directly bind to Rac1 in a nucleotide-independent manner to promote its polyubiquitination at Lys147 and proteasomal degradation. These IAPs are also required for degradation of Rac1 upon CNF1 toxin treatment or RhoGDI depletion. Consistently, downregulation of XIAP or c-IAP1 by various strategies led to an increase in Rac1 protein levels in primary and tumour cells, leading to an elongated morphology and enhanced cell migration. Further, XIAP counteracts Rac1-dependent cellular polarization in the developing zebrafish hindbrain and promotes the delamination of neurons from the normal tissue architecture. These observations unveil an evolutionarily conserved role of IAPs in controlling Rac1 stability thereby regulating the plasticity of cell migration and morphogenesis.

  9. Inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear.

    PubMed

    Jiang, Lizhu; Mao, Rongrong; Tong, Jianbin; Li, Jinnan; Chai, Anping; Zhou, Qixin; Yang, Yuexiong; Wang, Liping; Li, Lingjiang; Xu, Lin

    2016-10-01

    Promoting extinction of fear memory is the main treatment of fear disorders, especially post-traumatic stress disorder (PTSD). However, fear extinction is often incomplete in these patients. Our previous study had shown that Rac1 activity in hippocampus plays a crucial role in the learning of contextual fear memory in rats. Here, we further investigated whether Rac1 activity also modulated the extinction of contextual fear memory. We found that massed extinction obviously upregulated hippocampal Rac1 activity and induced long-term extinction of contextual fear in rats. Intrahippocampal injection of the Rac1 inhibitor NSC23766 prevents extinction of contextual fear in massed extinction training rats. In contrast, long-spaced extinction downregulated Rac1 activity and caused less extinction. And Rac1 activator CN04-A promotes extinction of contextual fear in long-spaced extinction rats. Our study demonstrates that inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear, suggesting that modulating Rac1 activity of the hippocampus may be promising therapy of fear disorders.

  10. Mitochondrial Dysfunction in Human Leukemic Stem/Progenitor Cells upon Loss of RAC2

    PubMed Central

    Capala, Marta E.; Maat, Henny; Bonardi, Francesco; van den Boom, Vincent; Kuipers, Jeroen; Vellenga, Edo; Giepmans, Ben N. G.; Schuringa, Jan Jacob

    2015-01-01

    Leukemic stem cells (LSCs) reside within bone marrow niches that maintain their relatively quiescent state and convey resistance to conventional treatment. Many of the microenvironmental signals converge on RAC GTPases. Although it has become clear that RAC proteins fulfill important roles in the hematopoietic compartment, little has been revealed about the downstream effectors and molecular mechanisms. We observed that in BCR-ABL-transduced human hematopoietic stem/progenitor cells (HSPCs) depletion of RAC2 but not RAC1 induced a marked and immediate decrease in proliferation, progenitor frequency, cobblestone formation and replating capacity, indicative for reduced self-renewal. Cell cycle analyses showed reduced cell cycle activity in RAC2-depleted BCR-ABL leukemic cobblestones coinciding with an increased apoptosis. Moreover, a decrease in mitochondrial membrane potential was observed upon RAC2 downregulation, paralleled by severe mitochondrial ultrastructural malformations as determined by automated electron microscopy. Proteome analysis revealed that RAC2 specifically interacted with a set of mitochondrial proteins including mitochondrial transport proteins SAM50 and Metaxin 1, and interactions were confirmed in independent co-immunoprecipitation studies. Downregulation of SAM50 also impaired the proliferation and replating capacity of BCR-ABL-expressing cells, again associated with a decreased mitochondrial membrane potential. Taken together, these data suggest an important role for RAC2 in maintaining mitochondrial integrity. PMID:26016997

  11. Inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear.

    PubMed

    Jiang, Lizhu; Mao, Rongrong; Tong, Jianbin; Li, Jinnan; Chai, Anping; Zhou, Qixin; Yang, Yuexiong; Wang, Liping; Li, Lingjiang; Xu, Lin

    2016-10-01

    Promoting extinction of fear memory is the main treatment of fear disorders, especially post-traumatic stress disorder (PTSD). However, fear extinction is often incomplete in these patients. Our previous study had shown that Rac1 activity in hippocampus plays a crucial role in the learning of contextual fear memory in rats. Here, we further investigated whether Rac1 activity also modulated the extinction of contextual fear memory. We found that massed extinction obviously upregulated hippocampal Rac1 activity and induced long-term extinction of contextual fear in rats. Intrahippocampal injection of the Rac1 inhibitor NSC23766 prevents extinction of contextual fear in massed extinction training rats. In contrast, long-spaced extinction downregulated Rac1 activity and caused less extinction. And Rac1 activator CN04-A promotes extinction of contextual fear in long-spaced extinction rats. Our study demonstrates that inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear, suggesting that modulating Rac1 activity of the hippocampus may be promising therapy of fear disorders. PMID:27329554

  12. 76 FR 17106 - Secure Rural Schools Resource Advisory Committee (RAC) Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-28

    ... Forest Service Secure Rural Schools Resource Advisory Committee (RAC) Meeting AGENCY: Forest Service, U.S... the Secure Rural Schools Act and Community Self-Determination Act, Public Law 110-343. SUMMARY: On... Schools Resource Advisory Committee (RAC). The public is invited to attend the meeting and provide...

  13. A Critical Role for Rac1 in Tumor Progression of Human Colorectal Adenocarcinoma Cells

    PubMed Central

    Espina, Carolina; Céspedes, María Virtudes; García-Cabezas, Miguel Angel; del Pulgar, María Teresa Gómez; Boluda, Alicia; Oroz, Lourdes García; Cejas, Paloma; Nistal, Manuel; Mangues, Ramón; Lacal, Juan Carlos

    2008-01-01

    Colorectal adenocarcinoma is the second cause of cancer mortality in developed countries. Rac1 is a member of the family of Rho GTPases that regulates many intracellular signaling pathways, including those involved in tumorigenesis, invasion, and metastasis. We have investigated the role of Rac1 in colorectal tumor progression by genetic modification of the human colorectal adenocarcinoma cell line SW620 to either overexpress Rac1 or lack Rac1 expression. Tumor behavior was studied by orthotopic injection of stably modified cell lines into the cecal wall of athymic nude mice, a model that replicates the histopathological appearance and clinical behavior of human colorectal adenocarcinoma in humans. While overexpression of Rac1 resulted in an accelerated tumorigenic process, inducing a faster mortality rate, inhibition of Rac1 completely suppressed tumor formation. These results suggest that Rac1 plays a major role in colorectal adenocarcinoma progression. Finally, interference with Rac1 function may provide an important tool to block the malignant phenotype of colorectal adenocarcinoma cells. PMID:18165265

  14. Independent contractors or employees? Reducing reclassification risks.

    PubMed

    Moore, W B; Groth, C D

    1993-05-01

    With the aggressive stance taken by the IRS regarding worker classification, many organizations may be risking significant retroactive assessments with respect to the use of independent contractors. Employers should be aware of the 20 primary factors considered by the IRS when examining independent contractor relationships and prepare in advance for IRS classification review or audit.

  15. 48 CFR 1553.209 - Contractor qualifications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor qualifications. 1553.209 Section 1553.209 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS FORMS Prescription of Forms 1553.209 Contractor qualifications....

  16. 78 FR 11164 - Policy on Contractor Profits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-15

    ... Defense Acquisition Regulations System Policy on Contractor Profits AGENCY: Defense Acquisition..., at 703- 693-1145. Please cite NDAA FY 2013 Profit Policy Public Meeting. SUPPLEMENTARY INFORMATION... Year 2013. Section 804, Department of Defense Policy on Contractor Profits, included a requirement...

  17. 48 CFR 253.209 - Contractor qualifications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Contractor qualifications. 253.209 Section 253.209 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS FORMS Prescription of Forms 253.209 Contractor qualifications....

  18. 48 CFR 253.209 - Contractor qualifications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Contractor qualifications. 253.209 Section 253.209 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS FORMS Prescription of Forms 253.209 Contractor qualifications....

  19. 48 CFR 253.209 - Contractor qualifications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Contractor qualifications. 253.209 Section 253.209 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS FORMS Prescription of Forms 253.209 Contractor qualifications....

  20. 48 CFR 253.209 - Contractor qualifications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Contractor qualifications. 253.209 Section 253.209 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS FORMS Prescription of Forms 253.209 Contractor qualifications....

  1. 18 CFR 3b.4 - Government contractors.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Government contractors. 3b.4 Section 3b.4 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION... PERSONAL INFORMATION General § 3b.4 Government contractors. Systems of records operated by a...

  2. 49 CFR 10.27 - Government contractors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Government contractors. 10.27 Section 10.27 Transportation Office of the Secretary of Transportation MAINTENANCE OF AND ACCESS TO RECORDS PERTAINING TO INDIVIDUALS Maintenance of Records § 10.27 Government contractors. When the Department provides by a...

  3. 49 CFR 10.27 - Government contractors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Government contractors. 10.27 Section 10.27 Transportation Office of the Secretary of Transportation MAINTENANCE OF AND ACCESS TO RECORDS PERTAINING TO INDIVIDUALS Maintenance of Records § 10.27 Government contractors. When the Department provides by a...

  4. 4 CFR 83.19 - Government contractors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 4 Accounts 1 2010-01-01 2010-01-01 false Government contractors. 83.19 Section 83.19 Accounts GOVERNMENT ACCOUNTABILITY OFFICE RECORDS PRIVACY PROCEDURES FOR PERSONNEL RECORDS § 83.19 Government contractors. When GAO provides by a contract for the operation by or on behalf of GAO of a system of...

  5. 18 CFR 3b.4 - Government contractors.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Government contractors. 3b.4 Section 3b.4 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION... PERSONAL INFORMATION General § 3b.4 Government contractors. Systems of records operated by a...

  6. 18 CFR 3b.4 - Government contractors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Government contractors. 3b.4 Section 3b.4 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION... PERSONAL INFORMATION General § 3b.4 Government contractors. Systems of records operated by a...

  7. 4 CFR 83.19 - Government contractors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 4 Accounts 1 2013-01-01 2013-01-01 false Government contractors. 83.19 Section 83.19 Accounts GOVERNMENT ACCOUNTABILITY OFFICE RECORDS PRIVACY PROCEDURES FOR PERSONNEL RECORDS § 83.19 Government contractors. When GAO provides by a contract for the operation by or on behalf of GAO of a system of...

  8. 18 CFR 3b.4 - Government contractors.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Government contractors. 3b.4 Section 3b.4 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION... PERSONAL INFORMATION General § 3b.4 Government contractors. Systems of records operated by a...

  9. 18 CFR 3b.4 - Government contractors.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Government contractors. 3b.4 Section 3b.4 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION... PERSONAL INFORMATION General § 3b.4 Government contractors. Systems of records operated by a...

  10. 49 CFR 10.27 - Government contractors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Government contractors. 10.27 Section 10.27 Transportation Office of the Secretary of Transportation MAINTENANCE OF AND ACCESS TO RECORDS PERTAINING TO INDIVIDUALS Maintenance of Records § 10.27 Government contractors. When the Department provides by a...

  11. 4 CFR 83.19 - Government contractors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 4 Accounts 1 2014-01-01 2013-01-01 true Government contractors. 83.19 Section 83.19 Accounts GOVERNMENT ACCOUNTABILITY OFFICE RECORDS PRIVACY PROCEDURES FOR PERSONNEL RECORDS § 83.19 Government contractors. When GAO provides by a contract for the operation by or on behalf of GAO of a system of...

  12. 4 CFR 83.19 - Government contractors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 4 Accounts 1 2011-01-01 2011-01-01 false Government contractors. 83.19 Section 83.19 Accounts GOVERNMENT ACCOUNTABILITY OFFICE RECORDS PRIVACY PROCEDURES FOR PERSONNEL RECORDS § 83.19 Government contractors. When GAO provides by a contract for the operation by or on behalf of GAO of a system of...

  13. 49 CFR 10.27 - Government contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Government contractors. 10.27 Section 10.27 Transportation Office of the Secretary of Transportation MAINTENANCE OF AND ACCESS TO RECORDS PERTAINING TO INDIVIDUALS Maintenance of Records § 10.27 Government contractors. When the Department provides by a...

  14. 4 CFR 83.19 - Government contractors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 4 Accounts 1 2012-01-01 2012-01-01 false Government contractors. 83.19 Section 83.19 Accounts GOVERNMENT ACCOUNTABILITY OFFICE RECORDS PRIVACY PROCEDURES FOR PERSONNEL RECORDS § 83.19 Government contractors. When GAO provides by a contract for the operation by or on behalf of GAO of a system of...

  15. 49 CFR 10.27 - Government contractors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Government contractors. 10.27 Section 10.27 Transportation Office of the Secretary of Transportation MAINTENANCE OF AND ACCESS TO RECORDS PERTAINING TO INDIVIDUALS Maintenance of Records § 10.27 Government contractors. When the Department provides by a...

  16. 7 CFR 1726.27 - Contractor's bonds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Contractor's bonds. 1726.27 Section 1726.27 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES General § 1726.27 Contractor's bonds. (a)...

  17. 7 CFR 1726.27 - Contractor's bonds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Contractor's bonds. 1726.27 Section 1726.27 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES General § 1726.27 Contractor's bonds. (a)...

  18. 7 CFR 1726.27 - Contractor's bonds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Contractor's bonds. 1726.27 Section 1726.27 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES General § 1726.27 Contractor's bonds. (a)...

  19. 7 CFR 1726.27 - Contractor's bonds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 11 2014-01-01 2014-01-01 false Contractor's bonds. 1726.27 Section 1726.27 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES General § 1726.27 Contractor's bonds. (a)...

  20. 7 CFR 1726.27 - Contractor's bonds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Contractor's bonds. 1726.27 Section 1726.27 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES General § 1726.27 Contractor's bonds. (a)...

  1. 48 CFR 4.102 - Contractor's signature.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contractor's signature. 4... ADMINISTRATIVE MATTERS Contract Execution 4.102 Contractor's signature. (a) Individuals. A contract with an... be signed by that individual, and the signature shall be followed by the individual's typed,...

  2. Inhibition of Rac controls NPM-ALK-dependent lymphoma development and dissemination.

    PubMed

    Colomba, A; Giuriato, S; Dejean, E; Thornber, K; Delsol, G; Tronchère, H; Meggetto, F; Payrastre, B; Gaits-Iacovoni, F

    2011-06-01

    Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) is a tyrosine kinase oncogene responsible for the pathogenesis of the majority of human ALK-positive lymphomas. We recently reported that it activated the Rac1 GTPase in anaplastic large-cell lymphoma (ALCL), leading to Rac-dependent formation of active invadopodia required for invasiveness. Herein, we went further into the study of this pathway and used the inhibitor of Rac, NSC23766, to validate its potential as a molecular target in ALCL in vitro and in vivo in a xenograft model and in a conditional model of NPM-ALK transgenic mice. Our data demonstrate that Rac regulates important effectors of NPM-ALK-induced transformation such as Erk1/2, p38 and Akt. Moreover, inhibition of Rac signaling abrogates NPM-ALK-elicited disease progression and metastasis in mice, highlighting the potential of small GTPases and their regulators as additional therapic targets in lymphomas.

  3. Aegeline from Aegle marmelos stimulates glucose transport via Akt and Rac1 signaling, and contributes to a cytoskeletal rearrangement through PI3K/Rac1.

    PubMed

    Gautam, Sudeep; Ishrat, Nayab; Singh, Rohit; Narender, Tadigoppula; Srivastava, Arvind K

    2015-09-01

    Aegeline is an alkaloidal-amide, isolated from the leaves of Aegle marmelos and have shown antihyperglycemic as well as antidyslipidemic activities in the validated animal models of type 2 diabetes mellitus. Here we delineate, aegeline enhanced GLUT4 translocation mediated 2-deoxy-glucose uptake in both time and concentration-dependent manner. 2-deoxy-glucose uptake was completely stymied by the transport inhibitors (wortmannin and genistein) in C2C12 myotubes. Pharmacological inhibition of Akt (also known as protein kinase B) and Ras-related C3 botulinum toxin substrate 1 (Rac1) suggest that both Akt and Rac1 operate aegeline-stimulated glucose transport via distinct parallel pathways. Moreover, aegeline activates p21 protein-activated kinase 1 (PAK1) and cofilin (an actin polymerization regulator). Rac1 inhibitor (Rac1 inhib II) and PAK1 inhibitor (IPA-3) completely blocked aegeline-induced phosphorylation of cofilin and p21 protein-activated kinase 1 (PAK1). In summary, these findings suggest that aegeline stimulates the glucose transport through Akt and Rac1 dependent distinct parallel pathways and have cytoskeletal roles via stimulation of the PI3-kinase-Rac1-PAK1-cofilin pathway in the skeletal muscle cells. Therefore, multiple targets of aegeline in the improvement of insulin sensitivity of the skeletal muscle cells may be suggested. PMID:26102565

  4. Aegeline from Aegle marmelos stimulates glucose transport via Akt and Rac1 signaling, and contributes to a cytoskeletal rearrangement through PI3K/Rac1.

    PubMed

    Gautam, Sudeep; Ishrat, Nayab; Singh, Rohit; Narender, Tadigoppula; Srivastava, Arvind K

    2015-09-01

    Aegeline is an alkaloidal-amide, isolated from the leaves of Aegle marmelos and have shown antihyperglycemic as well as antidyslipidemic activities in the validated animal models of type 2 diabetes mellitus. Here we delineate, aegeline enhanced GLUT4 translocation mediated 2-deoxy-glucose uptake in both time and concentration-dependent manner. 2-deoxy-glucose uptake was completely stymied by the transport inhibitors (wortmannin and genistein) in C2C12 myotubes. Pharmacological inhibition of Akt (also known as protein kinase B) and Ras-related C3 botulinum toxin substrate 1 (Rac1) suggest that both Akt and Rac1 operate aegeline-stimulated glucose transport via distinct parallel pathways. Moreover, aegeline activates p21 protein-activated kinase 1 (PAK1) and cofilin (an actin polymerization regulator). Rac1 inhibitor (Rac1 inhib II) and PAK1 inhibitor (IPA-3) completely blocked aegeline-induced phosphorylation of cofilin and p21 protein-activated kinase 1 (PAK1). In summary, these findings suggest that aegeline stimulates the glucose transport through Akt and Rac1 dependent distinct parallel pathways and have cytoskeletal roles via stimulation of the PI3-kinase-Rac1-PAK1-cofilin pathway in the skeletal muscle cells. Therefore, multiple targets of aegeline in the improvement of insulin sensitivity of the skeletal muscle cells may be suggested.

  5. Regulation of Synaptic Rac1 Activity, Long-Term Potentiation Maintenance, and Learning and Memory by BCR and ABR Rac GTPase-Activating Proteins

    PubMed Central

    Oh, Daeyoung; Han, Seungnam; Seo, Jinsoo; Lee, Jae-Ran; Choi, Jeonghoon; Groffen, John; Kim, Karam; Cho, Yi Sul; Choi, Han-Saem; Shin, Hyewon; Woo, Jooyeon; Won, Hyejung; Park, Soon Kwon; Kim, Soo-Young; Jo, Jihoon; Whitcomb, Daniel J.; Cho, Kwangwook; Kim, Hyun; Bae, Yong Chul; Heisterkamp, Nora; Choi, Se-Young; Kim, Eunjoon

    2016-01-01

    Rho family small GTPases are important regulators of neuronal development. Defective Rho regulation causes nervous system dysfunctions including mental retardation and Alzheimer’s disease. Rac1, a member of the Rho family, regulates dendritic spines and excitatory synapses, but relatively little is known about how synaptic Rac1 is negatively regulated. Breakpoint cluster region (BCR) is a Rac GTPase-activating protein known to form a fusion protein with the c-Abl tyrosine kinase in Philadelphia chromosome-positive chronic myelogenous leukemia. Despite the fact that BCR mRNAs are abundantly expressed in the brain, the neural functions of BCR protein have remained obscure. We report here that BCR and its close relative active BCR-related (ABR) localize at excitatory synapses and directly interact with PSD-95, an abundant postsynaptic scaffolding protein. Mice deficient for BCR or ABR show enhanced basal Rac1 activity but only a small increase in spine density. Importantly, mice lacking BCR or ABR exhibit a marked decrease in the maintenance, but not induction, of long-term potentiation, and show impaired spatial and object recognition memory. These results suggest that BCR and ABR have novel roles in the regulation of synaptic Rac1 signaling, synaptic plasticity, and learning and memory, and that excessive Rac1 activity negatively affects synaptic and cognitive functions. PMID:20962234

  6. Inhibition of Rac1 activity by controlled release of NSC23766 from chitosan microspheres effectively ameliorates osteoarthritis development in vivo

    PubMed Central

    Zhu, Shouan; Lu, Ping; Liu, Huanhuan; Chen, Pengfei; Wu, Yan; Wang, Yanyan; Sun, Heng; Zhang, Xiaolei; Xia, Qingqing; Heng, Boon Chin; Zhou, Yiting; Ouyang, Hong Wei

    2015-01-01

    Background Osteoarthritis (OA) is a degenerative joint disease characterised by cartilage degradation and chondrocyte hypertrophy. A recent study showed that Rac1 promoted expression of MMP13 and chondrocyte hypertrophy within the growth plate. These findings warrant further investigations on the roles of Rac1 in OA development and therapy in animal models. Objective To investigate the role and mechanistic pathway of Rac1 involvement in pathological changes of OA chondrocytes in vitro and OA development in vivo, as well as to develop a strategy of modulating Rac1 activity for OA treatment. Material and methods OA and normal cartilage from human or mice were used for immunohistochemical study and Rac1 activity assay. Chondrocytes treated with IL1β and the untreated control were subjected to the Rac1 activity assay. Chondrocytes transfected with CA-Rac1, DN-Rac1 or GFP were cultured under conditions for inducing calcification. To evaluate the effect of Rac1 in OA development, an OA model was created by anterior cruciate ligament transection in mice. CA-Rac1, DN-Rac1 and GFP lentivirus, or NSC23766, were injected intra-articularly. Joints were subjected to histological analysis. Results It was found that there is aberrant Rac1 activation in human OA cartilage. Rac1 activity could also be elevated by IL1β. Additionally, activated Rac1 promoted expression of MMP13, ADAMTS-5 and COLX by chondrocytes, partially through the β-catenin pathway. Moreover, activation of Rac1 in knee joints by CA-Rac1 lentivirus accelerated OA progression, while inhibition of Rac1 activity by DN-Rac1 lentivirus or Rac1 inhibitor NSC23766 delayed OA development. Therefore, we developed a strategy of controlled release of NSC23766 from chitosan microspheres to OA joints, which effectively protected cartilage from destruction. Conclusions These findings demonstrated that Rac1 activity is implicated in OA development. Also, controlled release of Rac1 inhibitor is a promising strategy for OA

  7. Hippocampal Activation of Rac1 Regulates the Forgetting of Object Recognition Memory.

    PubMed

    Liu, Yunlong; Du, Shuwen; Lv, Li; Lei, Bo; Shi, Wei; Tang, Yikai; Wang, Lianzhang; Zhong, Yi

    2016-09-12

    Forgetting is a universal feature for most types of memories. The best-defined and extensively characterized behaviors that depict forgetting are natural memory decay and interference-based forgetting [1, 2]. Molecular mechanisms underlying the active forgetting remain to be determined for memories in vertebrates. Recent progress has begun to unravel such mechanisms underlying the active forgetting [3-11] that is induced through the behavior-dependent activation of intracellular signaling pathways. In Drosophila, training-induced activation of the small G protein Rac1 mediates natural memory decay and interference-based forgetting of aversive conditioning memory [3]. In mice, the activation of photoactivable-Rac1 in recently potentiated spines in a motor learning task erases the motor memory [12]. These lines of evidence prompted us to investigate a role for Rac1 in time-based natural memory decay and interference-based forgetting in mice. The inhibition of Rac1 activity in hippocampal neurons through targeted expression of a dominant-negative Rac1 form extended object recognition memory from less than 72 hr to over 72 hr, whereas Rac1 activation accelerated memory decay within 24 hr. Interference-induced forgetting of this memory was correlated with Rac1 activation and was completely blocked by inhibition of Rac1 activity. Electrophysiological recordings of long-term potentiation provided independent evidence that further supported a role for Rac1 activation in forgetting. Thus, Rac1-dependent forgetting is evolutionarily conserved from invertebrates to vertebrates.

  8. Rac Regulates Giardia lamblia Encystation by Coordinating Cyst Wall Protein Trafficking and Secretion

    PubMed Central

    Krtková, Jana; Thomas, Elizabeth B.; Alas, Germain C. M.; Schraner, Elisabeth M.; Behjatnia, Habib R.; Hehl, Adrian B.

    2016-01-01

    ABSTRACT Encystation of the common intestinal parasite Giardia lamblia involves the production, trafficking, and secretion of cyst wall material (CWM). However, the molecular mechanism responsible for the regulation of these sequential processes remains elusive. Here, we examined the role of GlRac, Giardia’s sole Rho family GTPase, in the regulation of endomembrane organization and cyst wall protein (CWP) trafficking. Localization studies indicated that GlRac is associated with the endoplasmic reticulum (ER) and the Golgi apparatus-like encystation-specific vesicles (ESVs). Constitutive GlRac signaling increased levels of the ER marker PDI2, induced ER swelling, reduced overall CWP1 production, and promoted the early maturation of ESVs. Quantitative analysis of cells expressing constitutively active hemagglutinin (HA)-tagged GlRac (HA-RacCA) revealed fewer but larger ESVs than control cells. Consistent with the phenotype of premature maturation of ESVs in HA-RacCA-expressing cells, constitutive GlRac signaling resulted in increased CWP1 secretion and, conversely, morpholino depletion of GlRac blocked CWP1 secretion. Wild-type cells unexpectedly secreted large quantities of CWP1 into the medium, and free CWP1 was used cooperatively during cyst formation. These results, in part, could account for the previously reported observation that G. lamblia encysts more efficiently at high cell densities. These studies of GlRac show that it regulates encystation at several levels, and our findings support its coordinating role as a regulator of CWP trafficking and secretion. The central role of GlRac in regulating membrane trafficking and the cytoskeleton, both of which are essential to Giardia parasitism, further suggests its potential as a novel target for drug development to treat giardiasis. PMID:27555307

  9. Hippocampal Activation of Rac1 Regulates the Forgetting of Object Recognition Memory.

    PubMed

    Liu, Yunlong; Du, Shuwen; Lv, Li; Lei, Bo; Shi, Wei; Tang, Yikai; Wang, Lianzhang; Zhong, Yi

    2016-09-12

    Forgetting is a universal feature for most types of memories. The best-defined and extensively characterized behaviors that depict forgetting are natural memory decay and interference-based forgetting [1, 2]. Molecular mechanisms underlying the active forgetting remain to be determined for memories in vertebrates. Recent progress has begun to unravel such mechanisms underlying the active forgetting [3-11] that is induced through the behavior-dependent activation of intracellular signaling pathways. In Drosophila, training-induced activation of the small G protein Rac1 mediates natural memory decay and interference-based forgetting of aversive conditioning memory [3]. In mice, the activation of photoactivable-Rac1 in recently potentiated spines in a motor learning task erases the motor memory [12]. These lines of evidence prompted us to investigate a role for Rac1 in time-based natural memory decay and interference-based forgetting in mice. The inhibition of Rac1 activity in hippocampal neurons through targeted expression of a dominant-negative Rac1 form extended object recognition memory from less than 72 hr to over 72 hr, whereas Rac1 activation accelerated memory decay within 24 hr. Interference-induced forgetting of this memory was correlated with Rac1 activation and was completely blocked by inhibition of Rac1 activity. Electrophysiological recordings of long-term potentiation provided independent evidence that further supported a role for Rac1 activation in forgetting. Thus, Rac1-dependent forgetting is evolutionarily conserved from invertebrates to vertebrates. PMID:27593377

  10. Rac1 modulates acute and subacute genotoxin-induced hepatic stress responses, fibrosis and liver aging

    PubMed Central

    Bopp, A; Wartlick, F; Henninger, C; Kaina, B; Fritz, G

    2013-01-01

    To investigate the importance of the Ras-homologous GTPase Rac1 for the hepatic response to genotoxic insults and liver aging, rac1 was deleted in liver of mice by Mx1-Cre-based recombination. Knockout of rac1 caused complex changes in basal as well as doxorubicin and ionizing radiation-induced mRNA expression of various genotoxic stress response-related genes, including hspa1b, rad51, wrn and xpc. Rac1 deletion protected the liver from acute toxicity following doxorubicin treatment. Moreover, the level of S139 phosphorylated histone H2AX (γH2AX), which is indicative of DNA damage, and mRNA expression of pro-inflammatory (IL-6) and pro-fibrotic (CTGF, TGFβ, αSMA) factors were mitigated in rac1 knockout animals. By contrast, lack of rac1 promoted subacute hepatotoxicity, which was determined 3 weeks after injection of multiple low doses of doxorubicin by assaying the γH2AX level, mitotic index and pro-fibrotic gene expression. Regarding ionizing radiation, rac1 deficiency had no major effects on DNA damage induction or acute pro-inflammatory and pro-fibrotic stress responses. Mice lacking hepatic rac1 for extended period of time (15 months) revealed increased mRNA expression of fibrosis-related factors (CTGF, TGFβ, collagen, MMP1) and fibrotic tissue remodeling. In addition, protein expression of the senescence marker p16 was enhanced in the absence of rac1. Taken together, the data provide evidence that Rac1 is required for doxorubicin-induced DNA damage induction. It is also involved in both the acute and delayed inflammatory and fibrotic stress response in the liver following doxorubicin, but not ionizing radiation, treatment and, furthermore, protects against endogenous liver aging. PMID:23519127

  11. 48 CFR 970.4402 - Contractor purchasing system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor purchasing... SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Management and Operating Contractor Purchasing 970.4402 Contractor purchasing system....

  12. Technical assistance contractor management plan: Surface and ground water

    SciTech Connect

    Not Available

    1994-09-01

    This report presents the general management structure of the Technical Assistance Contractor (TAC) for the Uranium Mill Tailings Remedial Action (UMTRA) Project. This team is a partnership of four major private subcontractors, which teamed together, are striving to be the leader in environmental restoration of uranium mining and milling operations. It will provide a pool of experts in various aspects of the technologies necessary to accomplish this goal, available to DOE to deal with mission concerns. The report expands on goals from TAC`s mission statement, which include management concerns, environment, safety, and health, quality, technical support, communications, and personnel.

  13. The GTPase Rac regulates the proliferation and invasion of fibroblast-like synoviocytes from rheumatoid arthritis patients.

    PubMed

    Chan, Amanda; Akhtar, Mumtaz; Brenner, Max; Zheng, Yi; Gulko, Percio S; Symons, Marc

    2007-01-01

    Fibroblast-like synoviocytes (FLS) isolated from joints of rheumatoid arthritis (RA) patients display proliferative and invasive properties reminiscent of those of malignant tumor cells. Rac small GTPases play an important role in tumor cell proliferation and invasion. We therefore investigated the potential role of Rac proteins in the proliferative and invasive behavior of RA-FLS. We showed that inhibiting Rac activity with the Rac-specific small molecule inhibitor NSC23766 causes a strong inhibition of RA-FLS proliferation, without affecting cell survival. Rac inhibition also results in a strong reduction in RA-FLS invasion through reconstituted extracellular matrix and a less marked inhibition of two-dimensional migration as measured by monolayer wound healing. We also showed that small interfering RNA-mediated depletion of Rac1 inhibits RA-FLS proliferation and invasion to a similar extent as NSC23766. These results demonstrate for the first time that Rac proteins play an important role in the aggressive behavior of FLS isolated from RA patients. In addition, we observed that inhibiting Rac proteins prevents JNK activation and that the JNK inhibitor SP600125 strongly inhibits RA-FLS invasion, suggesting that Rac-mediated JNK activation contributes to the role of Rac proteins in the invasive behavior of RA-FLS. In conclusion, Rac-controlled signaling pathways may present a new source of drug targets for therapeutic intervention in RA.

  14. Eiger-induced cell death relies on Rac1-dependent endocytosis

    PubMed Central

    Ruan, W; Srinivasan, A; Lin, S; Kara, k-I; Barker, P A

    2016-01-01

    Signaling via tumor necrosis factor receptor (TNFR) superfamily members regulates cellular life and death decisions. A subset of mammalian TNFR proteins, most notably the p75 neurotrophin receptor (p75NTR), induces cell death through a pathway that requires activation of c-Jun N-terminal kinases (JNKs). However the receptor-proximal signaling events that mediate this remain unclear. Drosophila express a single tumor necrosis factor (TNF) ligand termed Eiger (Egr) that activates JNK-dependent cell death. We have exploited this model to identify phylogenetically conserved signaling events that allow Egr to induce JNK activation and cell death in vivo. Here we report that Rac1, a small GTPase, is specifically required in Egr-mediated cell death. rac1 loss of function blocks Egr-induced cell death, whereas Rac1 overexpression enhances Egr-induced killing. We identify Vav as a GEF for Rac1 in this pathway and demonstrate that dLRRK functions as a negative regulator of Rac1 that normally acts to constrain Egr-induced death. Thus dLRRK loss of function increases Egr-induced cell death in the fly. We further show that Rac1-dependent entry of Egr into early endosomes is a crucial prerequisite for JNK activation and for cell death and show that this entry requires the activity of Rab21 and Rab7. These findings reveal novel regulatory mechanisms that allow Rac1 to contribute to Egr-induced JNK activation and cell death. PMID:27054336

  15. Cooperation of distinct Rac-dependent pathways to stabilise E-cadherin adhesion

    PubMed Central

    Erasmus, Jennifer C.; Welsh, Natalie J.; Braga, Vania M.M.

    2015-01-01

    The precise mechanisms via which Rac1 is activated by cadherin junctions are not fully known. In keratinocytes Rac1 activation by cadherin junctions requires EGFR signalling, but how EGFR does so is unclear. To address which activator could mediate E-cadherin signalling to Rac1, we investigated EGFR and two Rac1 GEFs, SOS1 and DOCK180. EGFR RNAi prevented junction-induced Rac1 activation and led to fragmented localization of E-cadherin at cadherin contacts. In contrast, depletion of another EGFR family member, ErbB3, did not interfere with either process. DOCK180 RNAi, but not SOS1, prevented E-cadherin-induced Rac1 activation. However, in a strong divergence from EGFR RNAi phenotype, DOCK180 depletion did not perturb actin recruitment or cadherin localisation at junctions. Rather, reduced DOCK180 levels impaired the resistance to mechanical stress of pre-formed cell aggregates. Thus, within the same cell type, EGFR and DOCK180 regulate Rac1 activation by newly-formed contacts, but control separate cellular events that cooperate to stabilise junctions. PMID:25957131

  16. Role of the Rho GTPase Rac in the activation of the phagocyte NADPH oxidase

    PubMed Central

    Pick, Edgar

    2014-01-01

    The superoxide-generating NADPH oxidase of phagocytes consists of the membrane-associated cytochrome b558 (a heterodimer of Nox2 and p22phox) and 4 cytosolic components: p47phox, p67phox, p40phox, and the small GTPase, Rac, in complex with RhoGDI. Superoxide is produced by the NADPH-driven reduction of molecular oxygen, via a redox gradient located in Nox2. Electron flow in Nox2 is initiated by interaction with cytosolic components, which translocate to the membrane, p67phox playing the central role. The participation of Rac is expressed in the following sequence: (1) Translocation of the RacGDP-RhoGDI complex to the membrane; (2) Dissociation of RacGDP from RhoGDI; (3) GDP to GTP exchange on Rac, mediated by a guanine nucleotide exchange factor; (4) Binding of RacGTP to p67phox; (5) Induction of a conformational change in p67phox, promoting interaction with Nox2. The particular involvement of Rac in NADPH oxidase assembly serves as a paradigm for signaling by Rho GTPases, in general. PMID:24598074

  17. p190RhoGAP has cellular RacGAP activity regulated by a polybasic region.

    PubMed

    Lévay, Magdolna; Bartos, Balázs; Ligeti, Erzsébet

    2013-06-01

    p190RhoGAP is a GTPase-activating protein (GAP) known to regulate actin cytoskeleton dynamics by decreasing RhoGTP levels through activation of the intrinsic GTPase activity of Rho. Although the GAP domain of p190RhoGAP stimulates the intrinsic' GTPase activity of several Rho family members (Rho, Rac, Cdc42) under in vitro conditions, p190RhoGAP is generally regarded as a GAP for RhoA in the cell. The cellular RacGAP activity of the protein has not been proven directly. We have previously shown that the in vitro RacGAP and RhoGAP activity of p190RhoGAP was inversely regulated through a polybasic region of the protein. Here we provide evidence that p190RhoGAP shows remarkable GAP activity toward Rac also in the cell. The cellular RacGAP activity of p190RhoGAP requires an intact polybasic region adjacent to the GAP domain whereas the RhoGAP activity is inhibited by the same domain. Our data indicate that through its alternating RacGAP and RhoGAP activity, p190RhoGAP plays a more complex role in the Rac-Rho antagonism than it was realized earlier.

  18. Dimerization of DOCK2 is essential for DOCK2-mediated Rac activation and lymphocyte migration.

    PubMed

    Terasawa, Masao; Uruno, Takehito; Mori, Sayako; Kukimoto-Niino, Mutsuko; Nishikimi, Akihiko; Sanematsu, Fumiyuki; Tanaka, Yoshihiko; Yokoyama, Shigeyuki; Fukui, Yoshinori

    2012-01-01

    The migratory properties of lymphocytes depend on DOCK2, an atypical Rac activator predominantly expressed in hematopoietic cells. Although DOCK2 does not contain the Dbl homology domain typically found in guanine nucleotide exchange factors (GEFs), DOCK2 mediates the GTP-GDP exchange reaction for Rac via its DOCK homology region (DHR)-2 (also known as CZH2 or Docker) domain. DOCK2 DHR-2 domain is composed of three lobes, and Rac binding site and catalytic center are generated entirely from lobes B and C. On the other hand, lobe A has been implicated in dimer formation, yet its physiological significance remains unknown. Here, we report that lobe A-mediated DOCK2 dimerization is crucial for Rac activation and lymphocyte migration. We found that unlike wild-type DOCK2, DOCK2 mutant lacking lobe A failed to restore motility and polarity when expressed in thymoma cells and primary T cells lacking endogenous expression of DOCK2. Similar results were obtained with the DOCK2 point mutant having a defect in dimerization. Deletion of lobe A from the DHR-2 domain did not affect Rac GEF activity in vitro. However, fluorescence resonance energy transfer analyses revealed that lobe A is required for DOCK2 to activate Rac effectively during cell migration. Our results thus indicate that DOCK2 dimerization is functionally important under the physiological condition where only limited amounts of DOCK2 and Rac are localized to the plasma membrane. PMID:23050005

  19. Rac1 Protein Regulates Glycogen Phosphorylase Activation and Controls Interleukin (IL)-2-dependent T Cell Proliferation*

    PubMed Central

    Arrizabalaga, Onetsine; Lacerda, Hadriano M.; Zubiaga, Ana M.; Zugaza, José L.

    2012-01-01

    Small GTPases of the Rho family have been implicated in important cellular processes such as cell migration and adhesion, protein secretion, and/or gene transcription. In the lymphoid system, these GTPases participate in the signaling cascades that are activated after engagement of antigen receptors. However, little is known about the role that Rho GTPases play in IL-2-mediated responses. Here, we show that IL-2 induces Rac1 activation in Kit 225 T cells. We identified by mass spectrometry the muscle isoform of glycogen phosphorylase (PYGM) as a novel Rac1 effector molecule in IL-2-stimulated cells. The interaction between the active form of Rac1 (Rac1-GTP) and PYGM was established directly through a domain comprising amino acids 191–270 of PYGM that exhibits significant homology with the Rac binding domain of PAK1. The integrity of this region was crucial for PYGM activation. Importantly, IL-2-dependent cellular proliferation was inhibited upon blocking both the activation of Rac1 and the activity of PYGM. These results reveal a new role for Rac1 in cell signaling, showing that this GTPase triggers T cell proliferation upon IL-2 stimulation by associating with PYGM and modulating its enzymatic activity. PMID:22337875

  20. Rac-null leukocytes are associated with increased inflammation-mediated alveolar bone loss.

    PubMed

    Sima, Corneliu; Gastfreund, Shoshi; Sun, Chunxiang; Glogauer, Michael

    2014-02-01

    Periodontitis is characterized by altered host-biofilm interactions that result in irreversible inflammation-mediated alveolar bone loss. Genetic and epigenetic factors that predispose to ineffective control of biofilm composition and maintenance of tissue homeostasis are not fully understood. We elucidated how leukocytes affect the course of periodontitis in Rac-null mice. Mouse models of acute gingivitis and periodontitis were used to assess the early inflammatory response and patterns of chronicity leading to loss of alveolar bone due to inflammation in Rac-null mice. Leukocyte margination was differentially impaired in these mice during attachment in conditional Rac1-null (granulocyte/monocyte lineage) mice and during rolling and attachment in Rac2-null (all blood cells) mice. Inflammatory responses to subgingival ligatures, assessed by changes in peripheral blood differential leukocyte numbers, were altered in Rac-null compared with wild-type mice. In response to persistent subgingival ligature-mediated challenge, Rac-null mice had increased loss of alveolar bone with patterns of resorption characteristic of aggressive forms of periodontitis. These findings were partially explained by higher osteoclastic coverage of the bone-periodontal ligament interface in Rac-null compared with wild-type mice. In conclusion, this study demonstrates that leukocyte defects, such as decreased endothelial margination and tissue recruitment, are rate-limiting steps in the periodontal inflammatory process that lead to more aggressive forms of periodontitis.

  1. Cooperation of distinct Rac-dependent pathways to stabilise E-cadherin adhesion.

    PubMed

    Erasmus, Jennifer C; Welsh, Natalie J; Braga, Vania M M

    2015-09-01

    The precise mechanisms via which Rac1 is activated by cadherin junctions are not fully known. In keratinocytes Rac1 activation by cadherin junctions requires EGFR signalling, but how EGFR does so is unclear. To address which activator could mediate E-cadherin signalling to Rac1, we investigated EGFR and two Rac1 GEFs, SOS1 and DOCK180. EGFR RNAi prevented junction-induced Rac1 activation and led to fragmented localization of E-cadherin at cadherin contacts. In contrast, depletion of another EGFR family member, ErbB3, did not interfere with either process. DOCK180 RNAi, but not SOS1, prevented E-cadherin-induced Rac1 activation. However, in a strong divergence from EGFR RNAi phenotype, DOCK180 depletion did not perturb actin recruitment or cadherin localisation at junctions. Rather, reduced DOCK180 levels impaired the resistance to mechanical stress of pre-formed cell aggregates. Thus, within the same cell type, EGFR and DOCK180 regulate Rac1 activation by newly-formed contacts, but control separate cellular events that cooperate to stabilise junctions. PMID:25957131

  2. The Role of Rac1 in the Growth Cone Dynamics and Force Generation of DRG Neurons

    PubMed Central

    Sayyad, Wasim A.; Fabris, Paolo; Torre, Vincent

    2016-01-01

    We used optical tweezers, video imaging, immunocytochemistry and a variety of inhibitors to analyze the role of Rac1 in the motility and force generation of lamellipodia and filopodia from developing growth cones of isolated Dorsal Root Ganglia neurons. When the activity of Rac1 was inhibited by the drug EHop-016, the period of lamellipodia protrusion/retraction cycles increased and the lamellipodia retrograde flow rate decreased; moreover, the axial force exerted by lamellipodia was reduced dramatically. Inhibition of Arp2/3 by a moderate amount of the drug CK-548 caused a transient retraction of lamellipodia followed by a complete recovery of their usual motility. This recovery was abolished by the concomitant inhibition of Rac1. The filopodia length increased upon inhibition of both Rac1 and Arp2/3, but the speed of filopodia protrusion increased when Rac1 was inhibited and decreased instead when Arp2/3 was inhibited. These results suggest that Rac1 acts as a switch that activates upon inhibition of Arp2/3. Rac1 also controls the filopodia dynamics necessary to explore the environment. PMID:26766136

  3. Eiger-induced cell death relies on Rac1-dependent endocytosis.

    PubMed

    Ruan, W; Srinivasan, A; Lin, S; Kara, k-I; Barker, P A

    2016-01-01

    Signaling via tumor necrosis factor receptor (TNFR) superfamily members regulates cellular life and death decisions. A subset of mammalian TNFR proteins, most notably the p75 neurotrophin receptor (p75NTR), induces cell death through a pathway that requires activation of c-Jun N-terminal kinases (JNKs). However the receptor-proximal signaling events that mediate this remain unclear. Drosophila express a single tumor necrosis factor (TNF) ligand termed Eiger (Egr) that activates JNK-dependent cell death. We have exploited this model to identify phylogenetically conserved signaling events that allow Egr to induce JNK activation and cell death in vivo. Here we report that Rac1, a small GTPase, is specifically required in Egr-mediated cell death. rac1 loss of function blocks Egr-induced cell death, whereas Rac1 overexpression enhances Egr-induced killing. We identify Vav as a GEF for Rac1 in this pathway and demonstrate that dLRRK functions as a negative regulator of Rac1 that normally acts to constrain Egr-induced death. Thus dLRRK loss of function increases Egr-induced cell death in the fly. We further show that Rac1-dependent entry of Egr into early endosomes is a crucial prerequisite for JNK activation and for cell death and show that this entry requires the activity of Rab21 and Rab7. These findings reveal novel regulatory mechanisms that allow Rac1 to contribute to Egr-induced JNK activation and cell death. PMID:27054336

  4. 48 CFR 227.7108 - Contractor data repositories.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... contractor's data management and distribution responsibilities must be identified in the contract or the... require, as a minimum, the data repository management contractor to— (1) Establish and maintain...

  5. 48 CFR 227.7108 - Contractor data repositories.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... contractor's data management and distribution responsibilities must be identified in the contract or the... require, as a minimum, the data repository management contractor to— (1) Establish and maintain...

  6. 48 CFR 227.7108 - Contractor data repositories.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... contractor's data management and distribution responsibilities must be identified in the contract or the... require, as a minimum, the data repository management contractor to— (1) Establish and maintain...

  7. 48 CFR 227.7108 - Contractor data repositories.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contractor's data management and distribution responsibilities must be identified in the contract or the... require, as a minimum, the data repository management contractor to— (1) Establish and maintain...

  8. Single Nucleotide Polymorphisms that Increase Expression of the GTPase RAC1 are Associated with Ulcerative Colitis

    PubMed Central

    Muise, Aleixo M; Walters, Thomas; Xu, Wei; Shen-Tu, Grace; Guo, Cong-Hui; Fattouh, Ramzi; Lam, Grace Y; Wolters, Victorien M; Bennitz, Joshua; Van Limbergen, Johan; Renbaum, Paul; Kasirer, Yair; Ngan, Bo-Yee; Turner, Dan; Denson, Lee A; Sherman, Philip M; Duerr, Richard H; Cho, Judy; Lees, Charlie W; Satsangi, Jack; Wilson, David C; Paterson, Andrew D; Griffiths, Anne M; Glogauer, Michael; Silverberg, Mark S; Brumell, John H

    2011-01-01

    Background & Aims RAC1 is a GTPase that has an evolutionarily conserved role in coordinating immune defenses, from plants to mammals. Chronic inflammatory bowel diseases (IBD) are associated with dysregulation of immune defenses. We studied the role of RAC1 in IBD using human genetic and functional studies and animal models of colitis. Methods We used a candidate gene approach to HapMap-Tag single nucleotide polymorphisms (SNPs) in a discovery cohort; findings were confirmed in 2 additional cohorts. RAC1 mRNA expression was examined from peripheral blood cells of patients. Colitis was induced in mice with conditional disruption of Rac1 in phagocytes by administration of dextran sulphate sodium (DSS). Results We observed a genetic association between RAC1 with ulcerative colitis (UC) in a discovery cohort, 2 independent replication cohorts, and in combined analysis for the SNPs rs10951982 (Pcombined UC = 3.3 × 10–8, odds ratio [OR]=1.43 [1.26–1.63]) and rs4720672 (Pcombined UC=4.7 × 10–6, OR=1.36 [1.19–1.58]). Patients with IBD who had the rs10951982 risk allele had increased expression of RAC1, compared to those without this allele. Conditional disruption of Rac1 in macrophage and neutrophils of mice protected them against DSS-induced colitis. Conclusion Studies of human tissue samples and knockout mice demonstrated a role for the GTPase RAC1 in the development of UC; increased expression of RAC1 was associated with susceptibility to colitis. PMID:21684284

  9. Nuclear expression of Rac1 in cervical premalignant lesions and cervical cancer cells

    PubMed Central

    2012-01-01

    Background Abnormal expression of Rho-GTPases has been reported in several human cancers. However, the expression of these proteins in cervical cancer has been poorly investigated. In this study we analyzed the expression of the GTPases Rac1, RhoA, Cdc42, and the Rho-GEFs, Tiam1 and beta-Pix, in cervical pre-malignant lesions and cervical cancer cell lines. Methods Protein expression was analyzed by immunochemistry on 102 cervical paraffin-embedded biopsies: 20 without Squamous Intraepithelial Lesions (SIL), 51 Low- grade SIL, and 31 High-grade SIL; and in cervical cancer cell lines C33A and SiHa, and non-tumorigenic HaCat cells. Nuclear localization of Rac1 in HaCat, C33A and SiHa cells was assessed by cellular fractionation and Western blotting, in the presence or not of a chemical Rac1 inhibitor (NSC23766). Results Immunoreacivity for Rac1, RhoA, Tiam1 and beta-Pix was stronger in L-SIL and H-SIL, compared to samples without SIL, and it was significantly associated with the histological diagnosis. Nuclear expression of Rac1 was observed in 52.9% L-SIL and 48.4% H-SIL, but not in samples without SIL. Rac1 was found in the nucleus of C33A and SiHa cells but not in HaCat cells. Chemical inhibition of Rac1 resulted in reduced cell proliferation in HaCat, C33A and SiHa cells. Conclusion Rac1 is expressed in the nucleus of epithelial cells in SILs and cervical cancer cell lines, and chemical inhibition of Rac1 reduces cellular proliferation. Further studies are needed to better understand the role of Rho-GTPases in cervical cancer progression. PMID:22443139

  10. Rac1 inhibition negatively regulates transcriptional activity of the amyloid precursor protein gene.

    PubMed

    Wang, Pi-Lin; Niidome, Tetsuhiro; Akaike, Akinori; Kihara, Takeshi; Sugimoto, Hachiro

    2009-07-01

    Rac1, a member of the Rho family GTPases, participates in a variety of cellular functions including lamellipodia formation, actin cytoskeleton organization, cell growth, apoptosis, and neuronal development. Recent studies have implicated Rac1 in cytoskeletal abnormalities, production of reactive oxygen species, and generation of the amyloid beta-peptide (Abeta) observed in Alzheimer's disease. In this study, we examined the relationship between Rac1 and amyloid precursor protein (APP), because the abnormal proteolytic processing of APP is a pathologic feature of Alzheimer's disease. In primary hippocampal neurons, the Rac1-specific inhibitor NSC23766 decreased both Rac1 activity and APP protein levels in a concentration-dependent manner. To elucidate how NSC23766 decreases APP protein levels, we examined the effects of NSC23766 on APP processing, degradation, and biosynthesis. NSC23766 did not increase the levels of the proteolytic products of APP, sAPPalpha, Abeta40, and Abeta42. The proteasome inhibitor lactacystin did not reverse the NSC23766-induced decrease in APP protein levels. NSC23766 did, however, decrease the levels of both APP mRNA and APP protein. Decreased levels of APP mRNA and protein were also observed when HEK293 cells were transfected with an expression vector containing a dominant-negative Rac1 mutant or with siRNA targeting Rac1. By overexpressing progressively deleted fragments of the APP promoter in HEK293 cells, we identified a Rac1 response site at positions -233 to -41 bp in the APP promoter. Taken together, our results suggest that Rac1 regulates transcription of the APP gene in primary hippocampal neurons.

  11. Role of Rac1 GTPase in JNK signaling and delayed neuronal cell death following global cerebral ischemia.

    PubMed

    Zhang, Quan-Guang; Wang, Ruimin; Han, Dong; Dong, Yan; Brann, Darrell W

    2009-04-10

    The overall goal of this study was to determine the role of Rac1 in POSH/MLK/JNK signaling and delayed neuronal cell death following cerebral ischemia. Temporal studies revealed that Rac1 GTPase activation was significantly elevated in hippocampus CA1 at 10 min to 72 h after cerebral ischemia reperfusion, with peak levels 30 min to 6 h after reperfusion. Total Rac1 protein levels were not significantly changed following cerebral ischemia. Rac1 has been shown to interact with POSH (plenty of SH3s), a scaffold protein that binds to and regulates MLK3 and JNK activation. Co-immunoprecipitation (Co-IP) studies revealed that POSH-Rac1-MLK3 complex formation displayed a significant and prolonged elevation after reperfusion, with a correlative increase in phosphorylation/activation of MLK3 as compared to sham controls. Intracerebroventricular administration of Rac1 antisense oligonucleotides (AS-ODNs) significantly attenuated Rac1 levels and Rac1 activation at 30 min after reperfusion, with a correlated significant attenuation of POSH-MLK3-Rac1 complex formation and MLK3 activation in hippocampus CA1. Infusion of Rac1 AS-ODNs also significantly attenuated post-ischemic activation of JNK, downstream of MLK3, and strongly protected the hippocampus CA1 from ischemic damage. Missense oligos had no effect on any of the parameters measured. The Rac1 AS-ODNs results were further confirmed by administration of a Rac1 inhibitor (NSC23766), which markedly attenuated activation of Rac1 and JNK, and significantly attenuated apoptotic delayed neuronal cell death following cerebral ischemia. As a whole, these studies demonstrate an important role for Rac1 in activation of the prodeath MLK3-JNK kinase signaling pathway and delayed neuronal cell death following cerebral ischemia.

  12. List of Contractors to Support Anthrax Remediation

    SciTech Connect

    Judd, Kathleen S.; Lesperance, Ann M.

    2010-05-14

    This document responds to a need identified by private sector businesses for information on contractors that may be qualified to support building remediation efforts following a wide-area anthrax release.

  13. Contractor and government - Teamwork and commitment

    NASA Technical Reports Server (NTRS)

    Griffin, G. D.

    1985-01-01

    Procedures being implemented at NASA to improve cooperation with contractors and increase productivity are reviewed from the NASA point of view. The goals of the U.S. space program for the coming 25 years are listed, and the importance of the commercial utilization of space in these plans is stressed. Consideration is given to the ongoing American Productivity Center White-Collar Productivity-Improvement Project, the implementation of the recommendations of the 1984 NASA/Contractor Conferences in present and future contracts, and the use of incentive contracts to create situations in which both NASA and the contractor benefit from increased productivity. Future plans call for increased industry responsibility in managing and operating the STS; steamlining of Shuttle operations; advanced design-to-cost procedures, increased commonality, better NASA-contractor communications, and more use of CAD/CAM and robotics for the Space Station; and accommodation of greatly expanded private investment and exploitation of space.

  14. 48 CFR 725.703 - Contractor employees.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-financed contract, except that they must be citizens of a Geographic Code 935 country, or non-U.S. citizens... SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Source, Origin, and Nationality 725.703 Contractor employees....

  15. 76 FR 39015 - Contractor Performance Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-05

    ...) which has connectivity with the Past Performance Information Retrieval System (PPIRS). (b) Frequency and... evaluations to the Past Performance Information Retrieval System (PPIRS). Evaluation reports will be... AGENCY 48 CFR Part 1509, 1542 and 1552 Contractor Performance Information AGENCY:...

  16. 48 CFR 725.703 - Contractor employees.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Source, Origin, and Nationality 725.703 Contractor employees. (a... the contract is awarded to a U.S. firm, at least half of the supervisors, and any other specified...

  17. 24 CFR 242.53 - Excluded contractors.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES... made with a general contractor that has an identity of interest, as defined by HUD, with the...

  18. Tumor-related alternatively spliced Rac1b is not regulated by Rho-GDP dissociation inhibitors and exhibits selective downstream signaling.

    PubMed

    Matos, Paulo; Collard, John G; Jordan, Peter

    2003-12-12

    Rac1 is a member of the Rho family of small GTPases, which control signaling pathways that regulate actin cytoskeletal dynamics and gene transcription. Rac1 is activated by guanine nucleotide exchange factors and inactivated by GTPase-activating proteins. In addition, Rho-GDP dissociation inhibitors (Rho-GDIs) can inhibit Rac1 by sequestering it in the cytoplasm. We have found previously that colorectal tumors express an alternatively spliced variant, Rac1b, containing 19 additional amino acids following the switch II region. Here we characterized the regulation and downstream signaling of Rac1b. Although little Rac1b protein is expressed in cells, the amount of activated Rac1b protein often exceeds that of activated Rac1, suggesting that Rac1b contributes significantly to the downstream signaling of Rac in cells. The regulation of both Rac1 and Rac1b activities is dependent on guanine nucleotide exchange factors and GTPase-activating proteins, but the difference in their activation is mainly determined by the inability of Rac1b to interact with Rho-GDI. As a consequence, most Rac1b remains bound to the plasma membrane and is not sequestered by Rho-GDI in the cytoplasm. Unlike Rac1, activated Rac1b is unable to induce lamellipodia formation and is unable to bind and activate p21-activated protein kinase nor activate the downstream protein kinase JNK. However, both Rac1 and Rac1b are able to activate NFkappaB to the same extent. These data suggest that alternative splicing of Rac1 leads to a highly active Rac variant that differs in regulation and downstream signaling.

  19. Regulation of lymphatic-blood vessel separation by endothelial Rac1

    PubMed Central

    D'Amico, Gabriela; Jones, Dylan T.; Nye, Emma; Sapienza, Karen; Ramjuan, Antoine R.; Reynolds, Louise E.; Robinson, Stephen D.; Kostourou, Vassiliki; Martinez, Dolores; Aubyn, Deborah; Grose, Richard; Thomas, Gareth J.; Spencer-Dene, Bradley; Zicha, Daniel; Davies, Derek; Tybulewicz, Victor; Hodivala-Dilke, Kairbaan M.

    2009-01-01

    Sprouting angiogenesis and lymphatic-blood vessel segregation both involve the migration of endothelial cells, but the precise migratory molecules that govern the decision of blood vascular endothelial cells to segregate into lymphatic vasculature are unknown. Here, we deleted endothelial Rac1 in mice (Tie1-Cre+;Rac1fl/fl) and revealed, unexpectedly, that whereas blood vessel morphology appeared normal, lymphatic-blood vessel separation was impaired, with corresponding edema, haemorrhage and embryonic lethality. Importantly, normal levels of Rac1 were essential for directed endothelial cell migratory responses to lymphatic-inductive signals. Our studies identify Rac1 as a crucial part of the migratory machinery required for endothelial cells to separate and form lymphatic vasculature. PMID:19906871

  20. Novel aspects of the roles of Rac1 GTPase in the cardiovascular system.

    PubMed

    Sawada, Naoki; Li, Yuxin; Liao, James K

    2010-04-01

    Rac1 GTPase is an established master regulator of cell motility through cortical actin re-organization and of reactive oxygen species generation through regulation of NADPH oxidase activity. Numerous molecular and cellular studies have implicated Rac1 in various cardiovascular pathologies: vascular smooth muscle proliferation, cardiomyocyte hypertrophy, and endothelial cell shape change. The physiological relevance of these in vitro findings, however, is just beginning to be reassessed with the newly developed, conditional mouse mutagenesis technology. Conditional gene targeting has also revealed unexpected, cell type-specific roles of Rac1. The aim of this review is to summarize the recent advance made in Rac1 research in the cardiovascular system, with special focus on its novel roles in the regulation of endothelial function, angiogenesis, and endothelium-mediated neuroprotection.

  1. Rac1 Is a Critical Mediator of Endothelium-Derived Neurotrophic Activity

    PubMed Central

    Sawada, Naoki; Kim, Hyung-Hwan; Moskowitz, Michael A.; Liao, James K.

    2009-01-01

    The therapeutic potential of neurotrophic factors has been hampered by their inability to achieve adequate tissue penetration. Brain blood vessels, however, could be an alternative target for neuro-salvage therapies by virtue of their close proximity to neurons. Here we show that hemizygous deletion of Rac1 in mouse endothelial cells (ECs) attenuates brain injury and edema after focal cerebral ischemia. Microarray analysis of Rac1+/− ECs revealed enrichment of stress response genes, basement membrane components, and neurotrophic factors that could affect neuronal survival. Consistent with these expression profiles, endothelial Rac1 hemizygosity enhanced antioxidative and endothelial barrier capacities and potentiated paracrine neuroprotective activities through the up-regulation of the neurotrophic factor, artemin. Endothelial Rac1, therefore, could be an important therapeutic target for promoting endothelial barrier integrity and neurotrophic activity. PMID:19278959

  2. WAVE regulatory complex activation by cooperating GTPases Arf and Rac1.

    PubMed

    Koronakis, Vassilis; Hume, Peter J; Humphreys, Daniel; Liu, Tao; Hørning, Ole; Jensen, Ole N; McGhie, Emma J

    2011-08-30

    The WAVE regulatory complex (WRC) is a critical element in the control of actin polymerization at the eukaryotic cell membrane, but how WRC is activated remains uncertain. While Rho GTPase Rac1 can bind and activate WRC in vitro, this interaction is of low affinity, suggesting other factors may be important. By reconstituting WAVE-dependent actin assembly on membrane-coated beads in mammalian cell extracts, we found that Rac1 was not sufficient to engender bead motility, and we uncovered a key requirement for Arf GTPases. In vitro, Rac1 and Arf1 were individually able to bind weakly to recombinant WRC and activate it, but when both GTPases were bound at the membrane, recruitment and concomitant activation of WRC were dramatically enhanced. This cooperativity between the two GTPases was sufficient to induce WAVE-dependent bead motility in cell extracts. Our findings suggest that Arf GTPases may be central components in WAVE signalling, acting directly, alongside Rac1.

  3. 75 FR 60452 - Clean Water Act; Contractor Access to Confidential Business Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-30

    ... AGENCY Clean Water Act; Contractor Access to Confidential Business Information AGENCY: Environmental Protection Agency (EPA). ACTION: Notice. SUMMARY: The Environmental Protection Agency's (EPA) Office of Water... standards under the Clean Water Act (CWA). Interested persons may submit comments on this intended...

  4. 77 FR 65927 - 60-Day Notice of Proposed Information Collection: Office of Language Services Contractor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-31

    ... Notice of Proposed Information Collection: Office of Language Services Contractor Application Form ACTION...: LSApplications@state.gov . Mail: Department of State, Office of Language Services SA- 1, Fourteenth Floor, 2401 E....gov . SUPPLEMENTARY INFORMATION: Title of Information Collection: Office of Language...

  5. Perivascular deletion of murine Rac reverses the ratio of marrow arterioles and sinusoid vessels and alters hematopoiesis in vivo.

    PubMed

    Ciuculescu, Marioara F; Park, Shin-Young; Canty, Kimberly; Mathieu, Ronald; Silberstein, Leslie E; Williams, David A

    2015-05-14

    Hematopoietic stem cells (HSCs) are localized within specialized microenvironments throughout the BM. Nestin-expressing (Nestin(+)) mesenchymal stromal cells (MSCs) are important in the perivascular space. Rac is critical for MSC cell shape in vitro, whereas its function in MSCs in vivo remains poorly characterized. We hypothesized that deletion of Rac in the Nestin(+) cells would perturb the perivascular space, altering HSC localization and hematopoiesis. Nestin-Cre-directed excision of Rac1 in Rac3(-/-) mice reduces Nestin(+) cells in the marrow. We observed a 2.7-fold decrease in homing of labeled wild-type hematopoietic cells into Rac1(Δ/Δ)Rac3(-/-) mice compared with control mice. Rac1(Δ/Δ)Rac3(-/-) mice demonstrated a marked decrease in arterioles and an increase in the number and volume of venous sinusoids in the marrow that was associated with a reduction in the numbers of immunophenotypically and functionally-defined long-term HSCs in the marrow, a decrease in colony-forming cells and a reduction in circulating progenitors. Rac-deleted animals demonstrated a significant increase in trabecular bone. These data demonstrate that Rac GTPases play an important role in the integrity of perivascular space. Increased trabecular bone and sinusoidal space and decreased arteriolar volume in this model were associated with decreased HSC, underscoring the complexity of regulation of hematopoiesis in the perivascular space.

  6. Tiam1/Rac1 signals contribute to the proliferation and chemoresistance, but not motility, of chronic lymphocytic leukemia cells.

    PubMed

    Hofbauer, Sebastian W; Krenn, Peter W; Ganghammer, Sylvia; Asslaber, Daniela; Pichler, Ulrike; Oberascher, Karin; Henschler, Reinhard; Wallner, Michael; Kerschbaum, Hubert; Greil, Richard; Hartmann, Tanja N

    2014-04-01

    Signals from the tumor microenvironment promote the migration, survival, and proliferation of chronic lymphocytic leukemia (CLL) cells. Rho GTPases control various signaling pathways downstream of microenvironmental cues. Here, we analyze the function of Rac1 in the motility and proliferation of CLL cells. We found decreased transcription of the Rac guanine nucleotide exchange factors Tiam1 and Vav1 in unstimulated peripheral blood CLL cells with almost complete loss of Tiam1 but increased transcription of the potential Rac antagonist RhoH. Consistently, stimulation of CLL cells with the chemokine CXCL12 induced RhoA but not Rac1 activation, whereas chemokine-induced CLL cell motility was Rac1-independent. Coculture of CLL cells with activated T cells induced their activation and subsequent proliferation. Here, Tiam1 expression was induced in the malignant cells in line with increased Ki-67 and c-Myc expression. Rac1 or Tiam1 knockdown using siRNA or treatment with the Tiam1/Rac inhibitor NSC-23766 attenuated c-Myc transcription. Furthermore, treatment of CLL cells with NSC-23766 reduced their proliferation. Rac inhibition also antagonized the chemoresistance of activated CLL cells toward fludarabine. Collectively, our data suggest a dynamic regulation of Rac1 function in the CLL microenvironment. Rac inhibition could be of clinical use by selectively interfering with CLL cell proliferation and chemoresistance.

  7. 48 CFR 1509.170-8 - Contractor Performance Report.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... AGENCY ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Contractor Performance Evaluations 1509.170-8... categories and ratings used in the evaluation of contractor performance are described in the clause at 1552... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor...

  8. 48 CFR 52.247-28 - Contractor's Invoices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Contractor's Invoices. 52....247-28 Contractor's Invoices. As prescribed in 47.207-9(c), insert the following clause in... services: Contractor's Invoices (APR 1984) The Contractor shall submit itemized invoices as instructed...

  9. 48 CFR 52.241-5 - Contractor's Facilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Contractor's Facilities....241-5 Contractor's Facilities. As prescribed in 41.501(c)(4), insert a clause substantially the same as the following: Contractor's Facilities (FEB 1995) (a) The Contractor, at its expense,...

  10. 48 CFR 52.247-28 - Contractor's Invoices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 2 2014-10-01 2014-10-01 false Contractor's Invoices. 52....247-28 Contractor's Invoices. As prescribed in 47.207-9(c), insert the following clause in... services: Contractor's Invoices (APR 1984) The Contractor shall submit itemized invoices as instructed...

  11. 48 CFR 1845.607-170 - Contractor's approved scrap procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor's approved scrap... Contractor Inventory 1845.607-170 Contractor's approved scrap procedure. (a) When a contractor has an approved scrap procedure, certain property may be routinely disposed of in accordance with that...

  12. 48 CFR 1552.237-76 - Government-Contractor Relations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Government-Contractor... 1552.237-76 Government-Contractor Relations. As prescribed in 1537.110(g), insert the following clause: Government-Contractor Relations (JUN 1999) (a) The Government and the Contractor understand and agree...

  13. 48 CFR 52.247-28 - Contractor's Invoices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Contractor's Invoices. 52....247-28 Contractor's Invoices. As prescribed in 47.207-9(c), insert the following clause in... services: Contractor's Invoices (APR 1984) The Contractor shall submit itemized invoices as instructed...

  14. 48 CFR 52.247-28 - Contractor's Invoices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Contractor's Invoices. 52....247-28 Contractor's Invoices. As prescribed in 47.207-9(c), insert the following clause in... services: Contractor's Invoices (APR 1984) The Contractor shall submit itemized invoices as instructed...

  15. 48 CFR 52.247-28 - Contractor's Invoices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Contractor's Invoices. 52....247-28 Contractor's Invoices. As prescribed in 47.207-9(c), insert the following clause in... services: Contractor's Invoices (APR 1984) The Contractor shall submit itemized invoices as instructed...

  16. Coronin-1C Protein and Caveolin Protein Provide Constitutive and Inducible Mechanisms of Rac1 Protein Trafficking*

    PubMed Central

    Williamson, Rosalind C.; Cowell, Christopher A. M.; Reville, Thomas; Roper, James A.; Rendall, Thomas C. S.; Bass, Mark D.

    2015-01-01

    Sustained directional fibroblast migration requires both polarized activation of the protrusive signal, Rac1, and redistribution of inactive Rac1 from the rear of the cell so that it can be redistributed or degraded. In this work, we determine how alternative endocytic mechanisms dictate the fate of Rac1 in response to the extracellular matrix environment. We discover that both coronin-1C and caveolin retrieve Rac1 from similar locations at the rear and sides of the cell. We find that coronin-1C-mediated extraction, which is responsible for Rac1 recycling, is a constitutive process that maintains Rac1 protein levels within the cell. In the absence of coronin-1C, the effect of caveolin-mediated endocytosis, which targets Rac1 for proteasomal degradation, becomes apparent. Unlike constitutive coronin-1C-mediated trafficking, caveolin-mediated Rac1 endocytosis is induced by engagement of the fibronectin receptor syndecan-4. Such an inducible endocytic/degradation mechanism would predict that, in the presence of fibronectin, caveolin defines regions of the cell that are resistant to Rac1 activation but, in the absence of fibronectin leaves more of the membrane susceptible to Rac1 activation and protrusion. Indeed, we demonstrate that fibronectin-stimulated activation of Rac1 is accelerated in the absence of caveolin and that, when caveolin is knocked down, polarization of active Rac1 is lost in FRET experiments and culminates in shunting migration in a fibrous fibronectin matrix. Although the concept of polarized Rac1 activity in response to chemoattractants has always been apparent, our understanding of the balance between recycling and degradation explains how polarity can be maintained when the chemotactic gradient has faded. PMID:25925950

  17. GxcDD, a putative RacGEF, is involved in Dictyostelium development

    PubMed Central

    Mondal, Subhanjan; Neelamegan, Dhamodharan; Rivero, Francisco; Noegel, Angelika A

    2007-01-01

    Background Rho subfamily GTPases are implicated in a large number of actin-related processes. They shuttle from an inactive GDP-bound form to an active GTP-bound form. This reaction is catalysed by Guanine nucleotide exchange factor (GEFs). GTPase activating proteins (GAPs) help the GTPase return to the inactive GDP-bound form. The social amoeba Dictyostelium discoideum lacks a Rho or Cdc42 ortholog but has several Rac related GTPases. Compared to our understanding of the downstream effects of Racs our understanding of upstream mechanisms that activate Rac GTPases is relatively poor. Results We report on GxcDD (Guanine exchange factor for Rac GTPases), a Dictyostelium RacGEF. GxcDD is a 180-kDa multidomain protein containing a type 3 CH domain, two IQ motifs, three PH domains, a RhoGEF domain and an ArfGAP domain. Inactivation of the gene results in defective streaming during development under different conditions and a delay in developmental timing. The characterization of single domains revealed that the CH domain of GxcDD functions as a membrane association domain, the RhoGEF domain can physically interact with a subset of Rac GTPases, and the ArfGAP-PH tandem accumulates in cortical regions of the cell and on phagosomes. Our results also suggest that a conformational change may be required for activation of GxcDD, which would be important for its downstream signaling. Conclusion The data indicate that GxcDD is involved in proper streaming and development. We propose that GxcDD is not only a component of the Rac signaling pathway in Dictyostelium, but is also involved in integrating different signals. We provide evidence for a Calponin Homology domain acting as a membrane association domain. GxcDD can bind to several Rac GTPases, but its function as a nucleotide exchange factor needs to be studied further. PMID:17584488

  18. Mas Oncogene Signaling and Transformation Require the Small GTP-Binding Protein Rac

    PubMed Central

    Zohn, Irene E.; Symons, Marc; Chrzanowska-Wodnicka, Magdalena; Westwick, John K.; Der, Channing J.

    1998-01-01

    The Mas oncogene encodes a novel G-protein-coupled receptor that was identified originally as a transforming protein when overexpressed in NIH 3T3 cells. The mechanism and signaling pathways that mediate Mas transformation have not been determined. We observed that the foci of transformed NIH 3T3 cells caused by Mas were similar to those caused by activated Rho and Rac proteins. Therefore, we determined if Mas signaling and transformation are mediated through activation of a specific Rho family protein. First, we observed that, like activated Rac1, Mas cooperated with activated Raf and caused synergistic transformation of NIH 3T3 cells. Second, both Mas- and Rac1-transformed NIH 3T3 cells retained actin stress fibers and showed enhanced membrane ruffling. Third, like Rac, Mas induced lamellipodium formation in porcine aortic endothelial cells. Fourth, Mas and Rac1 strongly activated the JNK and p38, but not ERK, mitogen-activated protein kinases. Fifth, Mas and Rac1 stimulated transcription from common DNA promoter elements: NF-κB, serum response factor (SRF), Jun/ATF-2, and the cyclin D1 promoter. Finally, Mas transformation and some of Mas signaling (SRF and cyclin D1 but not NF-κB activation) were blocked by dominant negative Rac1. Taken together, these observations suggest that Mas transformation is mediated in part by activation of Rac-dependent signaling pathways. Thus, Rho family proteins are common mediators of transformation by a diverse variety of oncogene proteins that include Ras, Dbl family, and G-protein-coupled oncogene proteins. PMID:9488437

  19. Temporal-specific roles of Rac1 during vascular development and retinal angiogenesis.

    PubMed

    Nohata, Nijiro; Uchida, Yutaka; Stratman, Amber N; Adams, Ralf H; Zheng, Yi; Weinstein, Brant M; Mukouyama, Yoh-Suke; Gutkind, J Silvio

    2016-03-15

    Angiogenesis, the formation of new blood vessels by remodeling and growth of pre-existing vessels, is a highly orchestrated process that requires a tight balance between pro-angiogenic and anti-angiogenic factors and the integration of their corresponding signaling networks. The family of Rho GTPases, including RhoA, Rac1, and Cdc42, play a central role in many cell biological processes that involve cytoskeletal changes and cell movement. Specifically for Rac1, we have shown that excision of Rac1 using a Tie2-Cre animal line results in embryonic lethality in midgestation (embryonic day (E) 9.5), with multiple vascular defects. However, Tie2-Cre can be also expressed during vasculogenesis, prior to angiogenesis, and is active in some hematopoietic precursors that can affect vessel formation. To circumvent these limitations, we have now conditionally deleted Rac1 in a temporally controlled and endothelial-restricted fashion using Cdh5(PAC)-iCreERT2 transgenic mice. In this highly controlled experimental in vivo system, we now show that Rac1 is required for embryonic vascular integrity and angiogenesis, and for the formation of superficial and deep vascular networks in the post-natal developing retina, the latter involving a novel specific function for Rac1 in vertical blood vessel sprouting. Aligned with these findings, we show that RAC1 is spatially involved in endothelial cell migration, invasion, and radial sprouting activities in 3D collagen matrix in vitro models. Hence, Rac1 and its downstream molecules may represent potential anti-angiogeneic therapeutic targets for the treatment of many human diseases that involve aberrant neovascularization and blood vessel overgrowth. PMID:26872874

  20. Regulation of Rac1 activation by the low density lipoprotein receptor-related protein.

    PubMed

    Ma, Zhong; Thomas, Keena S; Webb, Donna J; Moravec, Radim; Salicioni, Ana Maria; Mars, Wendy M; Gonias, Steven L

    2002-12-23

    The low density lipoprotein receptor-related protein (LRP-1) binds and mediates the endocytosis of multiple ligands, transports the urokinase-type plasminogen activator receptor (uPAR) and other membrane proteins into endosomes, and binds intracellular adaptor proteins involved in cell signaling. In this paper, we show that in murine embryonic fibroblasts (MEFs) and L929 cells, LRP-1 functions as a major regulator of Rac1 activation, and that this activity depends on uPAR. LRP-1-deficient MEFs demonstrated increased Rac1 activation compared with LRP-1-expressing MEFs, and this property was reversed by expressing the VLDL receptor, a member of the same gene family as LRP-1, with overlapping ligand-binding specificity. Neutralizing the activity of LRP-1 with receptor-associated protein (RAP) increased Rac1 activation and cell migration in MEFs and L929 cells. The same parameters were unaffected by RAP in uPAR-/- MEFs, prepared from uPAR gene knockout embryos, and in uPAR-deficient LM-TK- cells. Untreated uPAR+/+ MEFs demonstrated substantially increased Rac1 activation compared with uPAR-/- MEFs. In addition to Rac1, LRP-1 suppressed activation of extracellular signal-regulated kinase (ERK) in MEFs; however, it was Rac1 (and not ERK) that was responsible for the effects of LRP-1 on MEF migration. Thus, LRP-1 regulates two signaling proteins in the same cell (Rac1 and ERK), both of which may impact on cell migration. In uPAR-negative cells, LRP-1 neutralization does not affect Rac1 activation, and other mechanisms by which LRP-1 may regulate cell migration are not unmasked.

  1. Rac2 Controls Tumor Growth, Metastasis and M1-M2 Macrophage Differentiation In Vivo

    PubMed Central

    Joshi, Shweta; Singh, Alok R.; Zulcic, Muamera; Bao, Lei; Messer, Karen; Ideker, Trey; Dutkowski, Janusz; Durden, Donald L.

    2014-01-01

    Although it is well-established that the macrophage M1 to M2 transition plays a role in tumor progression, the molecular basis for this process remains incompletely understood. Herein, we demonstrate that the small GTPase, Rac2 controls macrophage M1 to M2 differentiation and the metastatic phenotype in vivo. Using a genetic approach, combined with syngeneic and orthotopic tumor models we demonstrate that Rac2-/- mice display a marked defect in tumor growth, angiogenesis and metastasis. Microarray, RT-PCR and metabolomic analysis on bone marrow derived macrophages isolated from the Rac2-/- mice identify an important role for Rac2 in M2 macrophage differentiation. Furthermore, we define a novel molecular mechanism by which signals transmitted from the extracellular matrix via the α4β1 integrin and MCSF receptor lead to the activation of Rac2 and potentially regulate macrophage M2 differentiation. Collectively, our findings demonstrate a macrophage autonomous process by which the Rac2 GTPase is activated downstream of the α4β1 integrin and the MCSF receptor to control tumor growth, metastasis and macrophage differentiation into the M2 phenotype. Finally, using gene expression and metabolomic data from our Rac2-/- model, and information related to M1-M2 macrophage differentiation curated from the literature we executed a systems biologic analysis of hierarchical protein-protein interaction networks in an effort to develop an iterative interactome map which will predict additional mechanisms by which Rac2 may coordinately control macrophage M1 to M2 differentiation and metastasis. PMID:24770346

  2. Regulation of Rac1 and Reactive Oxygen Species Production in Response to Infection of Gastrointestinal Epithelia

    PubMed Central

    Ablack, Amber; Hall, Emily H.; Butcher, Lindsay D.; Bhattacharyya, Asima; Eckmann, Lars; Harris, Paul R.; Das, Soumita; Ernst, Peter B.; Crowe, Sheila E.

    2016-01-01

    Generation of reactive oxygen species (ROS) during infection is an immediate host defense leading to microbial killing. APE1 is a multifunctional protein induced by ROS and after induction, protects against ROS-mediated DNA damage. Rac1 and NAPDH oxidase (Nox1) are important contributors of ROS generation following infection and associated with gastrointestinal epithelial injury. The purpose of this study was to determine if APE1 regulates the function of Rac1 and Nox1 during oxidative stress. Gastric or colonic epithelial cells (wild-type or with suppressed APE1) were infected with Helicobacter pylori or Salmonella enterica and assessed for Rac1 and NADPH oxidase-dependent superoxide production. Rac1 and APE1 interactions were measured by co-immunoprecipitation, confocal microscopy and proximity ligation assay (PLA) in cell lines or in biopsy specimens. Significantly greater levels of ROS were produced by APE1-deficient human gastric and colonic cell lines and primary gastric epithelial cells compared to control cells after infection with either gastric or enteric pathogens. H. pylori activated Rac1 and Nox1 in all cell types, but activation was higher in APE1 suppressed cells. APE1 overexpression decreased H. pylori-induced ROS generation, Rac1 activation, and Nox1 expression. We determined that the effects of APE1 were mediated through its N-terminal lysine residues interacting with Rac1, leading to inhibition of Nox1 expression and ROS generation. APE1 is a negative regulator of oxidative stress in the gastrointestinal epithelium during bacterial infection by modulating Rac1 and Nox1. Our results implicate APE1 in novel molecular interactions that regulate early stress responses elicited by microbial infections. PMID:26761793

  3. Regulatory effect of Rac1 on vascular reactivity after hemorrhagic shock in rats.

    PubMed

    Li, Tao; Yang, Guangming; Xu, Jing; Zhu, Yu; Liu, Liangming

    2011-06-01

    We used isolated superior mesenteric arteries (SMAs) from hemorrhagic-shock rats and hypoxia-treated vascular smooth muscle cells (VSMCs; mimicking the shock state) to observe the effects of platelet-derived growth factor (PDGF; Rac1 stimulator) and NSC23766 (Rac1 antagonist) on vascular reactivity and the relationship with the Rho kinase-myosin light-chain phosphatase (MLCP) and p21-activated kinase (PAK)-myosin light-chain kinase (MLCK) signal pathway. The results indicated that the contractile responses of the SMAs and VSMCs were significantly increased at early shock or after transient hypoxia. NSC23766 (Rac1 antagonist) further increased, whereas PDGF (Rac1 stimulator) decreased the contractile responses of SMAs and VSMCs. In the late period of shock or prolonged hypoxia, the contractile responses of SMAs and VSMCs were significantly decreased; NSC23766 increased (whereas PDGF further decreased) the contractile response of the SMAs and VSMCs. Activation of Rac1 with PDGF significantly increased the activity of PAK and MLCP, and decreased Rho kinase and MLCK activity and 20-kDa myosin light-chain phosphorylation in VSMCs. The PAK inhibitor PAK-18 significantly antagonized the PDGF-induced decrease in MLCK activity, whereas the Rho kinase antagonist Y-27632 further enforced the PDGF-induced increase in MLCP activity. Simple fluid resuscitation did not improve but in combination with NSC23766 significantly improved vascular reactivity and animal survival at 24 hours. This suggested that Rac1 has an inhibitory effect on vasoreactivity after shock. Rac1-mediated regulation of vascular reactivity is mainly through activation of PAK, inhibition of MLCK and inhibition of Rho kinase, unpack the inhibition of Rho kinase to MLCP. Rac1 may be a potential target to treat vascular hyporeactivity in many critical conditions.

  4. Listeria monocytogenes induced Rac1-dependent signal transduction in endothelial cells.

    PubMed

    Schmeck, Bernd; Beermann, Wiebke; van Laak, Vincent; Opitz, Bastian; Hocke, Andreas C; Meixenberger, Karolin; Eitel, Julia; Chakraborty, Trinad; Schmidt, Gudula; Barth, Holger; Suttorp, Norbert; Hippenstiel, Stefan

    2006-11-30

    Infection of endothelial cells by Listeria monocytogenes is an essential step in the pathogenesis of listeriosis. Small GTPases of the Rho family act as molecular switches in signal transduction. We tested the hypothesis that Rho GTPases contribute to the regulation of cytokine expression following L. monocytogenes infection. L. monocytogenes induced release of distinct CC and CXC, as well as Th1 and Th2 cytokines and growth factors by endothelial cells and activated RhoA and Rac1. Inhibition of Rac1 by inhibitor Nsc23766 reduced cytokine expression, and slightly yet significantly the uptake of bacteria. Blocking of Rho proteins by Clostridium difficile toxin B-10463 (TcdB) reduced Listeria-dependent cytokine expression, whereas activating Rho proteins by Escherichia coli CNF1 increased it. We analyzed regulation of IL-8 expression in more detail: Listeria-induced IL-8 release was reduced by inhibition of RhoA, Rac1 and Cdc42 (TcdB) or Rac1 while blocking of RhoA/B/C by Clostridium limosum C3 fusion toxin (C3FT) or Rho kinase by Y27632 reduced cytokine expression only slightly. Activation of RhoA, Rac1 and Cdc42 (CNF1), but not of RhoA alone (CNF(Y)), enhanced Listeria-dependent IL-8 release significantly. Furthermore, inhibition of RhoA, Rac1 and Cdc42 (TcdB) and Rac1 (Nsc23766), but not of RhoA (C3FT) reduced Listeria-related recruitment of NF-kappaB/p65 and RNA polymerase II to the il8 promoter, as well as acetylation of histone H4 and Ser10/Lys14-phosphorylation/acetylation of histone H3 at the il8 gene promoter in HUVEC. In conclusion, Rac1 contributed to L. monocytogenes-induced cytokine expression by human endothelial cells.

  5. Audit of the Department of Energy`s management of field contractor employees assigned to headquarters and other federal agencies

    SciTech Connect

    1997-12-05

    The Department of Energy (Department) has spent at least $76 million annually for field contractor employee support in Headquarters and other Federal agencies. The employees were to provide technical expertise and experience critical to Department operations and programs. Overall, the audit was performed to determine if the Department was managing the use of field contractor employees assigned to Headquarters and other Federal agencies. Specifically, it was to determine whether the Department reviews and evaluates the costs for the use of contractor employees, is reimbursed for contractors working at other Federal agencies, and had implemented corrective actions proposed as the result of a prior audit report on this subject. The Department did not effectively manage the use of field contractor employees assigned to Headquarters and other Federal agencies. Specifically, the Department was unable to identify all contractor employees assigned to the Washington, DC area or determine the total cost of maintaining them; some employees were providing routine support and administrative services rather than unique program expertise; and several of the Department`s contractors had assigned their employees to work in other agencies without receiving full reimbursement for their services. In addition, the Department did not fully implement the corrective actions it agreed to in the prior audit report. Recommendations were made for the Deputy Secretary based on the audit findings. 3 tabs.

  6. Rac1 contributes to trastuzumab resistance of breast cancer cells: Rac1 as a potential therapeutic target for the treatment of trastuzumab-resistant breast cancer.

    PubMed

    Dokmanovic, Milos; Hirsch, Dianne S; Shen, Yi; Wu, Wen Jin

    2009-06-01

    Although treatment with trastuzumab improves outcomes for women with ErbB2-positive breast cancer, many patients who achieve an initial response to trastuzumab subsequently acquire resistance within 1 year. Rac1, a Ras-like small GTPase, has been implicated in the control of cell growth and morphology and is believed to be associated with breast cancer progression and metastasis. Here, we show that when parental SKBR3 cells become resistant to trastuzumab, Rac1 activity is increased, leading to altered cell morphology, which is accompanied by significant cytoskeleton disorganization. Furthermore, both trastuzumab-mediated down-regulation of ErbB2 and epidermal growth factor-induced down-regulation of epidermal growth factor receptor are impaired in the trastuzumab-resistant SKBR3 cells, indicating that the endocytic down-regulation of ErbB receptors is compromised in the resistant cells. This results in an aberrant accumulation of ErbB2 on the cell surface and enhanced ErbB2 and extracellular signal-regulated kinase activity in trastuzumab-resistant SKBR3 cells. Additionally, overexpression of constitutively active Rac1G12V in parental SKBR3 cells reduces sensitivity to trastuzumab. After reduction of Rac1 activity by NSC23766, a specific Rac1 inhibitor, trastuzumab-resistant SKBR3 cells display a cellular morphology similar to parental SKBR3 cells. Moreover, we show that NSC23766 restores trastuzumab-mediated endocytic down-regulation of ErbB2 and reduces extracellular signal-regulated kinase activity in resistant SKBR3 cells. Our findings highlight an important role for Rac1 in trastuzumab resistance of human breast cancer cells and identify the impaired trastuzumab-mediated endocytic down-regulation of ErbB2 as a novel mechanism of trastuzumab resistance. The significant effects of NSC23766 on trastuzumab-resistant SKBR3 cells warrant further study of NSC23766 as a potential treatment of trastuzumab-resistant breast cancers.

  7. Fluctuation-based imaging of nuclear Rac1 activation by protein oligomerisation

    NASA Astrophysics Data System (ADS)

    Hinde, Elizabeth; Yokomori, Kyoko; Gaus, Katharina; Hahn, Klaus M.; Gratton, Enrico

    2014-02-01

    Here we describe a fluctuation-based method to quantify how protein oligomerisation modulates signalling activity of a multifunctional protein. By recording fluorescence lifetime imaging microscopy (FLIM) data of a FRET biosensor in a format that enables concomitant phasor and cross Number and Brightness (cN&B) analysis, we measure the nuclear dynamics of a Rac1 FRET biosensor and assess how Rac1 homo-oligomers (N&B) regulate Rac1 activity (hetero-oligomerisation with the biosensor affinity reagent, PBD, by FLIM-FRET) or interaction with an unknown binding partner (cN&B). The high spatiotemporal resolution of this method allowed us to discover that upon DNA damage monomeric and active Rac1 in the nucleus is segregated from dimeric and inactive Rac1 in the cytoplasm. This reorganisation requires Rac1 GTPase activity and is associated with an importin-α2 redistribution. Only with this multiplexed approach can we assess the oligomeric state a molecular complex must form in order to regulate a complex signalling network.

  8. Rac1 deficiency in the forebrain results in neural progenitor reduction and microcephaly

    PubMed Central

    Chen, Lei; Melendez, Jaime; Campbell, Kenneth; Kuan, Chia-Yi; Zheng, Yi

    2009-01-01

    The Rho family of small GTPases has been implicated in many neurological disorders including mental retardation, but whether they are involved in primary microcephaly (microcephalia vera) is unknown. Here, we examine the role of Rac1 in mammalian neural progenitors and forebrain development by a conditional gene-targeting strategy using the Foxg1-Cre line to delete floxed-Rac1 alleles in the telencephalic ventricular zone (VZ) of mouse embryos. We found that Rac1 deletion in the telencephalic VZ progenitors resulted in reduced sizes of both the striatum and cerebral cortex. Analyses further indicated that this abnormality was caused by accelerated cell-cycle exit and increased apoptosis during early corticogenesis (approximately E14.5), leading to a decrease of the neural progenitor pool in mid-to-late telencephalic development (E16.5 to E18.5). Moreover, the formation of patch-matrix compartments in the striatum was impaired by Rac1-deficiency. Together, these results suggest that Rac1 regulates self-renewal, survival, and differentiation of telencephalic neural progenitors, and that dysfunctions of Rac1 may lead to primary microcephaly. PMID:19007770

  9. PLC-gamma1 and Rac1 coregulate EGF-induced cytoskeleton remodeling and cell migration.

    PubMed

    Li, Siwei; Wang, Qian; Wang, Yi; Chen, Xinmei; Wang, Zhixiang

    2009-06-01

    It is well established that epidermal growth factor (EGF) induces the cytoskeleton reorganization and cell migration through two major signaling cascades: phospholipase C-gamma1 (PLC-gamma1) and Rho GTPases. However, little is known about the cross talk between PLC-gamma1 and Rho GTPases. Here we showed that PLC-gamma1 forms a complex with Rac1 in response to EGF. This interaction is direct and mediated by PLC-gamma1 Src homology 3 (SH3) domain and Rac1 (106)PNTP(109) motif. This interaction is critical for EGF-induced Rac1 activation in vivo, and PLC-gamma1 SH3 domain is actually a potent and specific Rac1 guanine nucleotide exchange factor in vitro. We have also demonstrated that the interaction between PLC-gamma1 SH3 domain and Rac1 play a significant role in EGF-induced F-actin formation and cell migration. We conclude that PLC-gamma1 and Rac1 coregulate EGF-induced cell cytoskeleton remodeling and cell migration by a direct functional interaction.

  10. Inhibition of Rac and ROCK signalling influence osteoblast adhesion, differentiation and mineralization on titanium topographies.

    PubMed

    Prowse, Paul D H; Elliott, Christopher G; Hutter, Jeff; Hamilton, Douglas W

    2013-01-01

    Reducing the time required for initial integration of bone-contacting implants with host tissues would be of great clinical significance. Changes in osteoblast adhesion formation and reorganization of the F-actin cytoskeleton in response to altered topography are known to be upstream of osteoblast differentiation, and these processes are regulated by the Rho GTPases. Rac and RhoA (through Rho Kinase (ROCK)). Using pharmacological inhibitors, we tested how inhibition of Rac and ROCK influenced osteoblast adhesion, differentiation and mineralization on PT (Pre-treated) and SLA (sandblasted large grit, acid etched) topographies. Inhibition of ROCK, but not Rac, significantly reduced adhesion number and size on PT, with adhesion size consistent with focal complexes. After 1 day, ROCK, but not Rac inhibition increased osteocalcin mRNA levels on SLA and PT, with levels further increasing at 7 days post seeding. ROCK inhibition also significantly increased bone sialoprotein expression at 7 days, but not BMP-2 levels. Rac inhibition significantly reduced BMP-2 mRNA levels. ROCK inhibition increased nuclear translocation of Runx2 independent of surface roughness. Mineralization of osteoblast cultures was greater on SLA than on PT, but was increased by ROCK inhibition and attenuated by Rac inhibition on both topographies. In conclusion, inhibition of ROCK signalling significantly increases osteoblast differentiation and biomineralization in a topographic dependent manner, and its pharmacological inhibition could represent a new therapeutic to speed bone formation around implanted metals and in regenerative medicine applications.

  11. Inhibition of Rac and ROCK Signalling Influence Osteoblast Adhesion, Differentiation and Mineralization on Titanium Topographies

    PubMed Central

    Prowse, Paul D. H.; Elliott, Christopher G.; Hutter, Jeff; Hamilton, Douglas W.

    2013-01-01

    Reducing the time required for initial integration of bone-contacting implants with host tissues would be of great clinical significance. Changes in osteoblast adhesion formation and reorganization of the F-actin cytoskeleton in response to altered topography are known to be upstream of osteoblast differentiation, and these processes are regulated by the Rho GTPases. Rac and RhoA (through Rho Kinase (ROCK)). Using pharmacological inhibitors, we tested how inhibition of Rac and ROCK influenced osteoblast adhesion, differentiation and mineralization on PT (Pre-treated) and SLA (sandblasted large grit, acid etched) topographies. Inhibition of ROCK, but not Rac, significantly reduced adhesion number and size on PT, with adhesion size consistent with focal complexes. After 1 day, ROCK, but not Rac inhibition increased osteocalcin mRNA levels on SLA and PT, with levels further increasing at 7 days post seeding. ROCK inhibition also significantly increased bone sialoprotein expression at 7 days, but not BMP-2 levels. Rac inhibition significantly reduced BMP-2 mRNA levels. ROCK inhibition increased nuclear translocation of Runx2 independent of surface roughness. Mineralization of osteoblast cultures was greater on SLA than on PT, but was increased by ROCK inhibition and attenuated by Rac inhibition on both topographies. In conclusion, inhibition of ROCK signalling significantly increases osteoblast differentiation and biomineralization in a topographic dependent manner, and its pharmacological inhibition could represent a new therapeutic to speed bone formation around implanted metals and in regenerative medicine applications. PMID:23505566

  12. Enucleation of cultured mouse fetal erythroblasts requires Rac GTPases and mDia2.

    PubMed

    Ji, Peng; Jayapal, Senthil Raja; Lodish, Harvey F

    2008-03-01

    Mammalian erythroid cells undergo enucleation, an asymmetric cell division involving extrusion of a pycnotic nucleus enveloped by the plasma membrane. The mechanisms that power and regulate the enucleation process have remained obscure. Here, we show that deregulation of Rac GTPase during a late stage of erythropoiesis completely blocks enucleation of cultured mouse fetal erythroblasts without affecting their proliferation or differentiation. Formation of the contractile actin ring (CAR) on the plasma membrane of enucleating erythroblasts was disrupted by inhibition of Rac GTPases. Furthermore, we demonstrate that mDia2, a downstream effector of Rho GTPases and a formin protein required for nucleation of unbranched actin filaments, is also required for enucleation of mouse fetal erythroblasts. We show that Rac1 and Rac2 bind to mDia2 in a GTP-dependent manner and that downregulation of mDia2, but not mDia1, by small interfering RNA (siRNA) during the late stages of erythropoiesis blocked both CAR formation and erythroblast enucleation. Additionally, overexpression of a constitutively active mutant of mDia2 rescued the enucleation defects induced by the inhibition of Rac GTPases. These results reveal important roles for Rac GTPases and their effector mDia2 in enucleation of mammalian erythroblasts.

  13. Rac1 GTPase silencing counteracts microgravity-induced effects on osteoblastic cells.

    PubMed

    Guignandon, Alain; Faure, Céline; Neutelings, Thibaut; Rattner, Aline; Mineur, Pierre; Linossier, Marie-Thérèse; Laroche, Norbert; Lambert, Charles; Deroanne, Christophe; Nusgens, Betty; Demets, René; Colige, Alain; Vico, Laurence

    2014-09-01

    Bone cells exposed to real microgravity display alterations of their cytoskeleton and focal adhesions, two major mechanosensitive structures. These structures are controlled by small GTPases of the Ras homology (Rho) family. We investigated the effects of RhoA, Rac1, and Cdc42 modulation of osteoblastic cells under microgravity conditions. Human MG-63 osteoblast-like cells silenced for RhoGTPases were cultured in the automated Biobox bioreactor (European Space Agency) aboard the Foton M3 satellite and compared to replicate ground-based controls. The cells were fixed after 69 h of microgravity exposure for postflight analysis of focal contacts, F-actin polymerization, vascular endothelial growth factor (VEGF) expression, and matrix targeting. We found that RhoA silencing did not affect sensitivity to microgravity but that Rac1 and, to a lesser extent, Cdc42 abrogation was particularly efficient in counteracting the spaceflight-related reduction of the number of focal contacts [-50% in silenced, scrambled (SiScr) controls vs. -15% for SiRac1], the number of F-actin fibers (-60% in SiScr controls vs. -10% for SiRac1), and the depletion of matrix-bound VEGF (-40% in SiScr controls vs. -8% for SiRac1). Collectively, these data point out the role of the VEGF/Rho GTPase axis in mechanosensing and validate Rac1-mediated signaling pathways as potential targets for counteracting microgravity effects. PMID:24903274

  14. Study of Vaccinia and Cowpox viruses' replication in Rac1-N17 dominant-negative cells

    PubMed Central

    Salgado, Ana Paula Carneiro; Soares-Martins, Jamária Adriana Pinheiro; Andrade, Luciana Garcia; Albarnaz, Jonas Dutra; Ferreira, Paulo César Peregrino; Kroon, Erna Geessien; Bonjardim, Cláudio Antônio

    2013-01-01

    Interfering with cellular signal transduction pathways is a common strategy used by many viruses to create a propitious intracellular environment for an efficient replication. Our group has been studying cellular signalling pathways activated by the orthopoxviruses Vaccinia (VACV) and Cowpox (CPXV) and their significance to viral replication. In the present study our aim was to investigate whether the GTPase Rac1 was an upstream signal that led to the activation of MEK/ERK1/2, JNK1/2 or Akt pathways upon VACV or CPXV' infections. Therefore, we generated stable murine fibroblasts exhibiting negative dominance to Rac1-N17 to evaluate viral growth and the phosphorylation status of ERK1/2, JNK1/2 and Akt. Our results demonstrated that VACV replication, but not CPXV, was affected in dominant-negative (DN) Rac1-N17 cell lines in which viral yield was reduced in about 10-fold. Viral late gene expression, but not early, was also reduced. Furthermore, our data showed that Akt phosphorylation was diminished upon VACV infection in DN Rac1-N17 cells, suggesting that Rac1 participates in the phosphoinositide-3 kinase pathway leading to the activation of Akt. In conclusion, our results indicate that while Rac1 indeed plays a role in VACV biology, perhaps another GTPase may be involved in CPXV replication. PMID:23903969

  15. Proapoptotic and antiinvasive activity of Rac1 small molecule inhibitors on malignant glioma cells

    PubMed Central

    Cardama, Georgina A; Gonzalez, Nazareno; Ciarlantini, Matias; Gandolfi Donadío, Lucia; Comin, María Julieta; Alonso, Daniel F; Menna, Pablo Lorenzano; Gomez, Daniel E

    2014-01-01

    Malignant gliomas are characterized by an intrinsic ability to invade diffusely throughout the normal brain tissue. This feature contributes mainly to the failure of existing therapies. Deregulation of small GTPases signaling, in particular Rac1 activity, plays a key role in the invasive phenotype of gliomas. Here we report the effect of ZINC69391, a specific Rac1 inhibitor developed by our group, on human glioma cell lines LN229 and U-87 MG. ZINC69391 is able to interfere with the interaction of Rac1 with Dock180, a relevant Rac1 activator in glioma invasion, and to reduce Rac1-GTP levels. The kinase Pak1, a downstream effector of Dock180–Rac1 signaling, was also downregulated upon ZINC69391 treatment. ZINC69391 reduced cell proliferation, arrested cells in G1 phase, and triggered apoptosis in glioma cells. Importantly, ZINC69391 dramatically affected cell migration and invasion in vitro, interfering with actin cytoskeleton dynamics. We also evaluated the effect of analog 1A-116, a compound derived from ZINC69391 structure. 1A-116 showed an improved antiproliferative and antiinvasive activity on glioma cells. These findings encourage further preclinical testing in clinically relevant animal models. PMID:25378937

  16. Rac1 GTPase silencing counteracts microgravity-induced effects on osteoblastic cells.

    PubMed

    Guignandon, Alain; Faure, Céline; Neutelings, Thibaut; Rattner, Aline; Mineur, Pierre; Linossier, Marie-Thérèse; Laroche, Norbert; Lambert, Charles; Deroanne, Christophe; Nusgens, Betty; Demets, René; Colige, Alain; Vico, Laurence

    2014-09-01

    Bone cells exposed to real microgravity display alterations of their cytoskeleton and focal adhesions, two major mechanosensitive structures. These structures are controlled by small GTPases of the Ras homology (Rho) family. We investigated the effects of RhoA, Rac1, and Cdc42 modulation of osteoblastic cells under microgravity conditions. Human MG-63 osteoblast-like cells silenced for RhoGTPases were cultured in the automated Biobox bioreactor (European Space Agency) aboard the Foton M3 satellite and compared to replicate ground-based controls. The cells were fixed after 69 h of microgravity exposure for postflight analysis of focal contacts, F-actin polymerization, vascular endothelial growth factor (VEGF) expression, and matrix targeting. We found that RhoA silencing did not affect sensitivity to microgravity but that Rac1 and, to a lesser extent, Cdc42 abrogation was particularly efficient in counteracting the spaceflight-related reduction of the number of focal contacts [-50% in silenced, scrambled (SiScr) controls vs. -15% for SiRac1], the number of F-actin fibers (-60% in SiScr controls vs. -10% for SiRac1), and the depletion of matrix-bound VEGF (-40% in SiScr controls vs. -8% for SiRac1). Collectively, these data point out the role of the VEGF/Rho GTPase axis in mechanosensing and validate Rac1-mediated signaling pathways as potential targets for counteracting microgravity effects.

  17. 48 CFR 252.229-7004 - Status of contractors as a direct contractor (Spain).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., development, maintenance, and operation of Spanish-American installations and facilities. (b) The Contractor..., articles 11, 14, 15, 17, and 18 of the Agreement on Friendship, Defense and Cooperation between the United..., and the Contractor should program its projects accordingly. Any delay or expense arising directly...

  18. Report on audit of management and operating contractor overtime costs

    SciTech Connect

    1995-10-01

    The Department of Energy (Department) uses contractors to operate its facilities. During Fiscal Year 1994, the Department`s management and operating contractors (contractors) had a total payroll of about $6.6 billion. Of this amount, about $251 million was compensation for overtime pay. The purpose of our audit was to evaluate contractor overtime payments for compliance with applicable regulations and contract provisions. Our objective was to determine whether the Department had controls in place to monitor and manage contractor overtime use.

  19. Deletion of Rac1GTPase in the Myeloid Lineage Protects against Inflammation-Mediated Kidney Injury in Mice.

    PubMed

    Nagase, Miki; Kurihara, Hidetake; Aiba, Atsu; Young, Morag J; Sakai, Tatsuo

    2016-01-01

    Macrophage-mediated inflammation has been implicated in various kidney diseases. We previously reported that Rac1, a Rho family small GTP-binding protein, was overactivated in several chronic kidney disease models, and that Rac1 inhibitors ameliorated renal injury, in part via inhibition of inflammation, but the detailed mechanisms have not been clarified. In the present study, we examined whether Rac1 in macrophages effects cytokine production and the inflammatory mechanisms contributing to kidney derangement. Myeloid-selective Rac1 flox control (M-Rac1 FC) and knockout (M-Rac1 KO) mice were generated using the cre-loxP system. Renal function under basal conditions did not differ between M-Rac1 FC and KO mice. Accordingly, lipopolysaccharide (LPS)-evoked kidney injury model was created. LPS elevated blood urea nitrogen and serum creatinine, enhanced expressions of kidney injury biomarkers, Kim-1 and Ngal, and promoted tubular injury in M-Rac1 FC mice. By contrast, deletion of myeloid Rac1 almost completely prevented the LPS-mediated renal impairment. LPS triggered a marked induction of macrophage-derived inflammatory cytokines, IL-6 and TNFα, in M-Rac1 FC mice, which was accompanied by Rac1 activation, stimulation of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and reactive oxygen species overproduction. These changes were inhibited in M-Rac1 KO mice. LPS evoked F4/80-positive macrophages accumulation in the kidney, which was not affected by myeloid Rac1 deficiency. We further tested the role of Rac1 signaling in cytokine production using macrophage cell line, RAW264.7. Exposure to LPS increased IL-6 and TNFα mRNA expression. The LPS-driven cytokine induction was dose-dependently blocked by the Rac1 inhibitor EHT1864, NADPH oxidase inhibitor diphenyleneiodonium, and NF-κB inhibitor BAY11-7082. In conclusion, genetic ablation of Rac1 in the myeloid lineage protected against LPS-induced renal inflammation and injury, by suppressing

  20. Deletion of Rac1GTPase in the Myeloid Lineage Protects against Inflammation-Mediated Kidney Injury in Mice.

    PubMed

    Nagase, Miki; Kurihara, Hidetake; Aiba, Atsu; Young, Morag J; Sakai, Tatsuo

    2016-01-01

    Macrophage-mediated inflammation has been implicated in various kidney diseases. We previously reported that Rac1, a Rho family small GTP-binding protein, was overactivated in several chronic kidney disease models, and that Rac1 inhibitors ameliorated renal injury, in part via inhibition of inflammation, but the detailed mechanisms have not been clarified. In the present study, we examined whether Rac1 in macrophages effects cytokine production and the inflammatory mechanisms contributing to kidney derangement. Myeloid-selective Rac1 flox control (M-Rac1 FC) and knockout (M-Rac1 KO) mice were generated using the cre-loxP system. Renal function under basal conditions did not differ between M-Rac1 FC and KO mice. Accordingly, lipopolysaccharide (LPS)-evoked kidney injury model was created. LPS elevated blood urea nitrogen and serum creatinine, enhanced expressions of kidney injury biomarkers, Kim-1 and Ngal, and promoted tubular injury in M-Rac1 FC mice. By contrast, deletion of myeloid Rac1 almost completely prevented the LPS-mediated renal impairment. LPS triggered a marked induction of macrophage-derived inflammatory cytokines, IL-6 and TNFα, in M-Rac1 FC mice, which was accompanied by Rac1 activation, stimulation of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and reactive oxygen species overproduction. These changes were inhibited in M-Rac1 KO mice. LPS evoked F4/80-positive macrophages accumulation in the kidney, which was not affected by myeloid Rac1 deficiency. We further tested the role of Rac1 signaling in cytokine production using macrophage cell line, RAW264.7. Exposure to LPS increased IL-6 and TNFα mRNA expression. The LPS-driven cytokine induction was dose-dependently blocked by the Rac1 inhibitor EHT1864, NADPH oxidase inhibitor diphenyleneiodonium, and NF-κB inhibitor BAY11-7082. In conclusion, genetic ablation of Rac1 in the myeloid lineage protected against LPS-induced renal inflammation and injury, by suppressing

  1. Deletion of Rac1GTPase in the Myeloid Lineage Protects against Inflammation-Mediated Kidney Injury in Mice

    PubMed Central

    Nagase, Miki; Kurihara, Hidetake; Aiba, Atsu; Young, Morag J.; Sakai, Tatsuo

    2016-01-01

    Macrophage-mediated inflammation has been implicated in various kidney diseases. We previously reported that Rac1, a Rho family small GTP-binding protein, was overactivated in several chronic kidney disease models, and that Rac1 inhibitors ameliorated renal injury, in part via inhibition of inflammation, but the detailed mechanisms have not been clarified. In the present study, we examined whether Rac1 in macrophages effects cytokine production and the inflammatory mechanisms contributing to kidney derangement. Myeloid-selective Rac1 flox control (M-Rac1 FC) and knockout (M-Rac1 KO) mice were generated using the cre-loxP system. Renal function under basal conditions did not differ between M-Rac1 FC and KO mice. Accordingly, lipopolysaccharide (LPS)-evoked kidney injury model was created. LPS elevated blood urea nitrogen and serum creatinine, enhanced expressions of kidney injury biomarkers, Kim-1 and Ngal, and promoted tubular injury in M-Rac1 FC mice. By contrast, deletion of myeloid Rac1 almost completely prevented the LPS-mediated renal impairment. LPS triggered a marked induction of macrophage-derived inflammatory cytokines, IL-6 and TNFα, in M-Rac1 FC mice, which was accompanied by Rac1 activation, stimulation of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and reactive oxygen species overproduction. These changes were inhibited in M-Rac1 KO mice. LPS evoked F4/80-positive macrophages accumulation in the kidney, which was not affected by myeloid Rac1 deficiency. We further tested the role of Rac1 signaling in cytokine production using macrophage cell line, RAW264.7. Exposure to LPS increased IL-6 and TNFα mRNA expression. The LPS-driven cytokine induction was dose-dependently blocked by the Rac1 inhibitor EHT1864, NADPH oxidase inhibitor diphenyleneiodonium, and NF-κB inhibitor BAY11-7082. In conclusion, genetic ablation of Rac1 in the myeloid lineage protected against LPS-induced renal inflammation and injury, by suppressing

  2. A 3D scanning confocal imaging method measures pit volume and captures the role of Rac in osteoclast function.

    PubMed

    Goldberg, Stephanie R; Georgiou, John; Glogauer, Michael; Grynpas, Marc D

    2012-07-01

    Modulation of Rho GTPases Rac1 and Rac2 impacts bone development, remodeling, and disease. In addition, GTPases are considered treatment targets for dysplastic and erosive bone diseases including Neurofibromatosis type 1. While it is important to understand the effects of Rac modulation on osteoclast function, two-dimensional resorption pit area measurements fall short in elucidating the volume aspect of bone resorption activity. Bone marrow from wild-type, Rac1 and Rac2 null mice was isolated from femora. Osteoclastogenesis was induced by adding M-CSF and RANKL in culture plates containing dentin slices and later stained with Picro Sirius Red to image resorption lacunae. Osteoclasts were also plated on glass cover slips and stained with phalloidin and DAPI to measure their surface area and the number of nuclei. Volumetric images were collected on a laser-scanning confocal system. Sirius Red confocal imaging provided an unambiguous, continuous definition of the pit boundary compared to reflected and transmitted light imaging. Rac1- and Rac2-deficient osteoclasts had fewer nuclei in comparison to wild-type counterparts. Rac1-deficient osteoclasts showed reduced resorption pit volume and surface area. Lacunae made by single Rac2 null osteoclasts had reduced volume but surprisingly surface area was unaffected. Surface area measures are deceiving since volume changed independently in resorption pits made by individual Rac2 null osteoclasts. Our innovative confocal imaging technique allows us to derive novel conclusions about Rac1 and Rac2 in osteoclast function. The data and method can be applied to study effects of genes and drugs including Rho GTPase modulators on osteoclast function and to develop pharmacotherapeutics to treat bone lytic disorders.

  3. Redundant and nonredundant roles for Cdc42 and Rac1 in lymphomas developed in NPM-ALK transgenic mice.

    PubMed

    Choudhari, Ramesh; Minero, Valerio Giacomo; Menotti, Matteo; Pulito, Roberta; Brakebusch, Cord; Compagno, Mara; Voena, Claudia; Ambrogio, Chiara; Chiarle, Roberto

    2016-03-10

    Increasing evidence suggests that Rho family GTPases could have a critical role in the biology of T-cell lymphoma. In ALK-rearranged anaplastic large cell lymphoma (ALCL), a specific subtype of T-cell lymphoma, the Rho family GTPases Cdc42 and Rac1 are activated by the ALK oncogenic activity. In vitro studies have shown that Cdc42 and Rac1 control rather similar phenotypes of ALCL biology such as the proliferation, survival, and migration of lymphoma cells. However, their role and possible redundancy in ALK-driven lymphoma development in vivo are still undetermined. We genetically deleted Cdc42 or Rac1 in a mouse model of ALK-rearranged ALCL to show that either Cdc42 or Rac1 deletion impaired lymphoma development, modified lymphoma morphology, actin filament distribution, and migration properties of lymphoma cells. Cdc42 or Rac1 deletion primarily affected survival rather than proliferation of lymphoma cells. Apoptosis of lymphoma cells was equally induced following Cdc42 or Rac1 deletion, was associated with upregulation of the proapoptotic molecule Bid, and was blocked by Bcl2 overexpression. Remarkably, Cdc42/Rac1 double deletion, but not Cdc42 or Rac1 single deletions, completely prevented NPM-ALK lymphoma dissemination in vivo. Thus, Cdc42 and Rac1 have nonredundant roles in controlling ALK-rearranged lymphoma survival and morphology but are redundant for lymphoma dissemination, suggesting that targeting both GTPases could represent a preferable therapeutic option for ALCL treatment.

  4. Molecular insights into DNA binding and anchoring by the Bacillus subtilis sporulation kinetochore-like RacA protein

    PubMed Central

    Schumacher, Maria A.; Lee, Jeehyun; Zeng, Wenjie

    2016-01-01

    During Bacillus subtilis sporulation, segregating sister chromosomes are anchored to cell poles and the chromosome is remodeled into an elongated structure called the axial filament. Data indicate that a developmentally regulated protein called RacA is involved in these functions. To gain insight into how RacA performs these diverse processes we performed a battery of structural and biochemical analyses. These studies show that RacA contains an N-terminal winged-helix-turn-helix module connected by a disordered region to a predicted coiled-coil domain. Structures capture RacA binding the DNA using distinct protein–protein interfaces and employing adjustable DNA docking modes. This unique DNA binding mechanism indicates how RacA can both specifically recognize its GC-rich centromere and also non-specifically bind the DNA. Adjacent RacA molecules within the protein–DNA structure interact leading to DNA compaction, suggesting a mechanism for axial filament formation. We also show that the RacA C-domain coiled coil directly contacts the coiled coil region of the polar protein DivIVA, which anchors RacA and hence the chromosome to the pole. Thus, our combined data reveal unique DNA binding properties by RacA and provide insight into the DNA remodeling and polar anchorage functions of the protein. PMID:27085804

  5. Structural and Functional Regulation of Tight Junctions by RhoA and Rac1 Small GTPases

    PubMed Central

    Jou, Tzuu-Shuh; Schneeberger, Eveline E.; James Nelson, W.

    1998-01-01

    Tight junctions (TJ) govern ion and solute diffusion through the paracellular space (gate function), and restrict mixing of membrane proteins and lipids between membrane domains (fence function) of polarized epithelial cells. We examined roles of the RhoA and Rac1 GTPases in regulating TJ structure and function in MDCK cells using the tetracycline repressible transactivator to regulate RhoAV14, RhoAN19, Rac1V12, and Rac1N17 expression. Both constitutively active and dominant negative RhoA or Rac1 perturbed TJ gate function (transepithelial electrical resistance, tracer diffusion) in a dose-dependent and reversible manner. Freeze-fracture EM and immunofluoresence microscopy revealed abnormal TJ strand morphology and protein (occludin, ZO-1) localization in RhoAV14 and Rac1V12 cells. However, TJ strand morphology and protein localization appeared normal in RhoAN19 and Rac1N17 cells. All mutant GTPases disrupted the fence function of the TJ (interdomain diffusion of a fluorescent lipid), but targeting and organization of a membrane protein in the apical membrane were unaffected. Expression levels and protein complexes of occludin and ZO-1 appeared normal in all mutant cells, although ZO-1 was more readily solubilized from RhoAV14-expressing cells with Triton X-100. These results show that RhoA and Rac1 regulate gate and fence functions of the TJ, and play a role in the spatial organization of TJ proteins at the apex of the lateral membrane. PMID:9660866

  6. Novel role of Rac1/WAVE signaling mechanism in regulation of the epithelial Na+ channel.

    PubMed

    Karpushev, Alexey V; Levchenko, Vladislav; Ilatovskaya, Daria V; Pavlov, Tengis S; Staruschenko, Alexander

    2011-05-01

    The epithelial Na(+) channel (ENaC) is an essential channel responsible for Na(+) reabsorption in the aldosterone-sensitive distal nephron. Consequently, ENaC is a major effector impacting systemic blood volume and pressure. We have shown recently that Rac1 increases ENaC activity, whereas Cdc42 fails to change channel activity. Here we tested whether Rac1 signaling plays a physiological role in modulating ENaC in native tissue and polarized epithelial cells. We found that Rac1 inhibitor NSC23766 markedly decreased ENaC activity in freshly isolated collecting ducts. Knockdown of Rac1 in native principal cells decreased ENaC-mediated sodium reabsorption and the number of channels at the apical plasma membrane. Members of the Wiskott-Aldrich syndrome protein (WASP) family play a central role in the control of the actin cytoskeleton. N-WASP functions downstream of Cdc42, whereas WAVEs are effectors of Rac1 activity. N-WASP and all 3 isoforms of WAVE significantly increased ENaC activity when coexpressed in Chinese hamster ovary cells. However, wiskostatin, an inhibitor of N-WASP, had no effect on ENaC activity. Immunoblotting demonstrated the presence of WAVE1 and WAVE2 and absence of N-WASP and WAVE3 in mpkCCD(c14) and M-1 principal cells. Immunohistochemistry analysis also revealed localization of WAVE1 and WAVE2 but not N-WASP in the cortical collecting duct of Sprague-Dawley rat kidneys. Moreover, patch clamp analysis revealed that Rac1 and WAVE1/2 are parts of the same signaling pathway with respect to activation of ENaC. Thus, our findings suggest that Rac1 is essential for ENaC activity and regulates the channel via WAVE proteins.

  7. 48 CFR 1609.471 - Contractor certification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... EMPLOYEES HEALTH BENEFITS ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Debarment... certifies, to the best of its knowledge and belief, that— (a) The Carrier and/or any of its Principals— (1... Standards for Health Benefits Carriers. (e) Nothing contained in the certification shall be construed...

  8. 48 CFR 1609.471 - Contractor certification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... EMPLOYEES HEALTH BENEFITS ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Debarment... certifies, to the best of its knowledge and belief, that— (a) The Carrier and/or any of its Principals— (1... Standards for Health Benefits Carriers. (e) Nothing contained in the certification shall be construed...

  9. 48 CFR 1845.502 - Contractor responsibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor responsibility. 1845.502 Section 1845.502 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CONTRACT MANAGEMENT GOVERNMENT PROPERTY Management of Government Property in the Possession...

  10. 39 CFR 230.6 - Contractor requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 39 Postal Service 1 2014-07-01 2014-07-01 false Contractor requirements. 230.6 Section 230.6 Postal Service UNITED STATES POSTAL SERVICE ORGANIZATION AND ADMINISTRATION OFFICE OF INSPECTOR GENERAL... satisfactory performance record (although a lack of relevant performance history shall not disqualify...

  11. 39 CFR 230.6 - Contractor requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 39 Postal Service 1 2013-07-01 2013-07-01 false Contractor requirements. 230.6 Section 230.6 Postal Service UNITED STATES POSTAL SERVICE ORGANIZATION AND ADMINISTRATION OFFICE OF INSPECTOR GENERAL... satisfactory performance record (although a lack of relevant performance history shall not disqualify...

  12. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... responsible for carrying out its obligations under the contract by— (1) Controlling the quality of supplies or... provide and maintain an inspection system or program for the control of quality that is acceptable to the Government (see 46.202). (c) The control of quality by the contractor may relate to, but is not limited...

  13. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... responsible for carrying out its obligations under the contract by— (1) Controlling the quality of supplies or... provide and maintain an inspection system or program for the control of quality that is acceptable to the Government (see 46.202). (c) The control of quality by the contractor may relate to, but is not limited...

  14. 40 CFR 68.87 - Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specialty work on or adjacent to a covered process. It does not apply to contractors providing incidental services which do not influence process safety, such as janitorial work, food and drink services, laundry... safety performance and programs. (2) The owner or operator shall inform contract owner or operator of...

  15. 28 CFR 513.36 - Government contractors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Government contractors. 513.36 Section 513.36 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE GENERAL MANAGEMENT AND ADMINISTRATION ACCESS TO RECORDS Release of Information General Provisions and Procedures § 513.36...

  16. 28 CFR 513.36 - Government contractors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Government contractors. 513.36 Section 513.36 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE GENERAL MANAGEMENT AND ADMINISTRATION ACCESS TO RECORDS Release of Information General Provisions and Procedures § 513.36...

  17. 28 CFR 513.36 - Government contractors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Government contractors. 513.36 Section 513.36 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE GENERAL MANAGEMENT AND ADMINISTRATION ACCESS TO RECORDS Release of Information General Provisions and Procedures § 513.36...

  18. 28 CFR 513.36 - Government contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Government contractors. 513.36 Section 513.36 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE GENERAL MANAGEMENT AND ADMINISTRATION ACCESS TO RECORDS Release of Information General Provisions and Procedures § 513.36...

  19. 28 CFR 513.36 - Government contractors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Government contractors. 513.36 Section 513.36 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE GENERAL MANAGEMENT AND ADMINISTRATION ACCESS TO RECORDS Release of Information General Provisions and Procedures § 513.36...

  20. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... responsible for carrying out its obligations under the contract by— (1) Controlling the quality of supplies or... provide and maintain an inspection system or program for the control of quality that is acceptable to the Government (see 46.202). (c) The control of quality by the contractor may relate to, but is not limited...

  1. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... responsible for carrying out its obligations under the contract by— (1) Controlling the quality of supplies or... provide and maintain an inspection system or program for the control of quality that is acceptable to the Government (see 46.202). (c) The control of quality by the contractor may relate to, but is not limited...

  2. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contractor responsibilities. 46.105 Section 46.105 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION..., subassemblies, etc., have an acceptable quality control system; and (4) Maintaining substantiating...

  3. Medicaid integrity program; limitation on contractor liability. Final rule.

    PubMed

    2007-11-30

    The Medicaid Integrity Program (the Program) provides that the Secretary promote the integrity of the Medicaid program by entering into contracts with contractors that will review the actions of individuals or entities furnishing items or services (whether fee-for-service, risk, or other basis) for which payment may be made under an approved State plan and/or any waiver of the plan approved under section 1115 of the Social Security Act; audit claims for payment of items or services furnished, or administrative services furnished, under a State plan; identify overpayments of individuals or entities receiving Federal funds; and educate providers of services, managed care entities, beneficiaries, and other individuals with respect to payment integrity and quality of care. This final rule will provide for limitations on a contractor's liability while performing these services under the Program. The final rule will, to the extent possible, employ the same or comparable standards and other substantive and procedural provisions as are contained in section 1157 (Limitation on Liability) of the Social Security Act.

  4. Management of government personal property in the hands of contractors. Handbook for contracting officers and staff

    SciTech Connect

    Not Available

    1982-04-01

    This manual is divided into three parts. Part One applies to the management of Government personal property within the Department of Energy in general terms. Part Two describes the specifics of the application of personal property management techniques to On-Site Contractors. Part three applies to Off-Site Contractors. Part One introduces the field of property management. It discusses: the legal basis and requirements established by Federal Statutes and the parallel authorities and responsibilities; the related evolution of the Department of Energy; the regulation system within the Federal Government and its implementation by the Department for personal property management. The life cycle of equipment is presented and how control over personal property is maintained through an accountability system. Classifications of property and contract clauses are discussed. The relationships of contracting officers and property administrators with contractors are presented in each of the discussions as appropriate. Part One consists of only one chapter and is applicable to the management of property utilized by all types of contractors. It provides the foundation to explore in some detail the actions and interactions that occur between the Department's procurement and property personnel and those of the contractor. This exploration in depth is made in Parts Two and Three.

  5. Regulation of Kir2.1 channels by the Rho-GTPase, Rac1

    PubMed Central

    Boyer, Stephanie B.; Slesinger, Paul A.; Jones, S.V. Penelope

    2010-01-01

    Mutations in Kir2.1 inwardly rectifying potassium channels are associated with Andersen Syndrome, a disease characterized by potentially fatal cardiac arrhythmias. While several Andersen-associated mutations affect membrane expression, the cytoplasmic signals that regulate Kir2.1 trafficking are poorly understood. Here, we investigated whether the Rho-family of small GTPases regulates trafficking of Kir2.1 channels expressed in HEK-293 cells. Treatment with C. difficile toxin B, an inhibitor of Rho-family GTPases, or co-expression of the dominant-negative mutant of Rac1 (Rac1DN) increased Kir2.1 current density ~2-fold. However, the dominant-negative forms of other Rho-family GTPases, RhoA or Cdc42, did not alter Kir2.1 currents, suggesting a selective effect of Rac1 on Kir2.1 current density. Single-channel properties (γ, τo, τc) and total protein levels of Kir2.1 were unchanged with co-expression of Rac1DN; however, studies using TIRF microscopy and CFP-tagged Kir2.1 revealed increased channel surface expression. Immunohistochemical detection of extracellularly-tagged HA-Kir2.1 channels showed that Rac1DN reduced channel internalization when co-expressed. Finally, the dominant-negative mutant of dynamin, which interferes with endocytosis, occluded the Rac1DN–induced potentiation of Kir2.1 currents. These data suggest that inhibition of Rac1 increases Kir2.1 surface expression by interfering with endocytosis, likely via a dynamin-dependent pathway. Surprisingly, Rac1DN did not alter Kir2.2 current density or internalization, suggesting subunit specific modulation of Kir2.1 channels. Consistent with this, construction of Kir2.1/2.2 chimeras implicated the C-terminal domain of Kir2.1 in mediating the potentiating effect of Rac1DN. This novel pathway for regulating surface expression of cardiac Kir2.1 channels could have implications for normal and diseased cardiac states. PMID:18932198

  6. Distinct predictive performance of Rac1 and Cdc42 in cell migration

    PubMed Central

    Yamao, Masataka; Naoki, Honda; Kunida, Katsuyuki; Aoki, Kazuhiro; Matsuda, Michiyuki; Ishii, Shin

    2015-01-01

    We propose a new computation-based approach for elucidating how signaling molecules are decoded in cell migration. In this approach, we performed FRET time-lapse imaging of Rac1 and Cdc42, members of Rho GTPases which are responsible for cell motility, and quantitatively identified the response functions that describe the conversion from the molecular activities to the morphological changes. Based on the identified response functions, we clarified the profiles of how the morphology spatiotemporally changes in response to local and transient activation of Rac1 and Cdc42, and found that Rac1 and Cdc42 activation triggers laterally propagating membrane protrusion. The response functions were also endowed with property of differentiator, which is beneficial for maintaining sensitivity under adaptation to the mean level of input. Using the response function, we could predict the morphological change from molecular activity, and its predictive performance provides a new quantitative measure of how much the Rho GTPases participate in the cell migration. Interestingly, we discovered distinct predictive performance of Rac1 and Cdc42 depending on the migration modes, indicating that Rac1 and Cdc42 contribute to persistent and random migration, respectively. Thus, our proposed predictive approach enabled us to uncover the hidden information processing rules of Rho GTPases in the cell migration. PMID:26634649

  7. Tum/RacGAP functions as a switch activating the Pav/kinesin-6 motor.

    PubMed

    Tao, Li; Fasulo, Barbara; Warecki, Brandt; Sullivan, William

    2016-01-01

    Centralspindlin is essential for central spindle and cleavage furrow formation. Drosophila centralspindlin consists of a kinesin-6 motor (Pav/kinesin-6) and a GTPase-activating protein (Tum/RacGAP). Centralspindlin localization to the central spindle is mediated by Pav/kinesin-6. While Tum/RacGAP has well-documented scaffolding functions, whether it influences Pav/kinesin-6 function is less well-explored. Here we demonstrate that both Pav/kinesin-6 and the centralspindlin complex (co-expressed Pav/Tum) have strong microtubule bundling activity. Centralspindlin also has robust plus-end-directed motility. In contrast, Pav/kinesin-6 alone cannot move microtubules. However, the addition of Tum/RacGAP or a 65 amino acid Tum/RacGAP fragment to Pav/kinesin-6 restores microtubule motility. Further, ATPase assays reveal that microtubule-stimulated ATPase activity of centralspindlin is seven times higher than that of Pav/kinesin-6. These findings are supported by in vivo studies demonstrating that in Tum/RacGAP-depleted S2 Drosophila cells, Pav/kinesin-6 exhibits severely reduced localization to the central spindle and an abnormal concentration at the centrosomes. PMID:27091402

  8. CD81 regulates cell migration through its association with Rac GTPase

    PubMed Central

    Tejera, Emilio; Rocha-Perugini, Vera; López-Martín, Soraya; Pérez-Hernández, Daniel; Bachir, Alexia I.; Horwitz, Alan Rick; Vázquez, Jesús; Sánchez-Madrid, Francisco; Yáñez-Mo, María

    2013-01-01

    CD81 is a member of the tetraspanin family that has been described to have a key role in cell migration of tumor and immune cells. To unravel the mechanisms of CD81-regulated cell migration, we performed proteomic analyses that revealed an interaction of the tetraspanin C-terminal domain with the small GTPase Rac. Direct interaction was confirmed biochemically. Moreover, microscopy cross-correlation analysis demonstrated the in situ integration of both molecules into the same molecular complex. Pull-down experiments revealed that CD81-Rac interaction was direct and independent of Rac activation status. Knockdown of CD81 resulted in enhanced protrusion rate, altered focal adhesion formation, and decreased cell migration, correlating with increased active Rac. Reexpression of wild-type CD81, but not its truncated form lacking the C-terminal cytoplasmic domain, rescued these effects. The phenotype of CD81 knockdown cells was mimicked by treatment with a soluble peptide with the C-terminal sequence of the tetraspanin. Our data show that the interaction of Rac with the C-terminal cytoplasmic domain of CD81 is a novel regulatory mechanism of the GTPase activity turnover. Furthermore, they provide a novel mechanism for tetraspanin-dependent regulation of cell motility and open new avenues for tetraspanin-targeted reagents by the use of cell-permeable peptides. PMID:23264468

  9. The Rac1 inhibitor NSC23766 suppresses CREB signaling by targeting NMDA receptor function.

    PubMed

    Hou, Hailong; Chávez, Andrés E; Wang, Chih-Chieh; Yang, Hongtian; Gu, Hua; Siddoway, Benjamin A; Hall, Benjamin J; Castillo, Pablo E; Xia, Houhui

    2014-10-15

    NMDA receptor signaling plays a complex role in CREB activation and CREB-mediated gene transcription, depending on the subcellular location of NMDA receptors, as well as how strongly they are activated. However, it is not known whether Rac1, the prototype of Rac GTPase, plays a role in neuronal CREB activation induced by NMDA receptor signaling. Here, we report that NSC23766, a widely used specific Rac1 inhibitor, inhibits basal CREB phosphorylation at S133 (pCREB) and antagonizes changes in pCREB levels induced by NMDA bath application in rat cortical neurons. Unexpectedly, we found that NSC23766 affects the levels of neuronal pCREB in a Rac1-independent manner. Instead, our results indicate that NSC23766 can directly regulate NMDA receptors as indicated by their strong effects on both exogenous and synaptically evoked NMDA receptor-mediated currents in mouse and rat neurons, respectively. Our findings strongly suggest that Rac1 does not affect pCREB signaling in cortical neurons and reveal that NSC23766 could be a novel NMDA receptor antagonist.

  10. Tiam1/Rac1 complex controls Il17a transcription and autoimmunity

    PubMed Central

    Kurdi, Ahmed T.; Bassil, Ribal; Olah, Marta; Wu, Chuan; Xiao, Sheng; Taga, Mariko; Frangieh, Michael; Buttrick, Thomas; Orent, William; Bradshaw, Elizabeth M.; Khoury, Samia J.; Elyaman, Wassim

    2016-01-01

    RORγt is a master transcription factor of Th17 cells and considered as a promising drug target for the treatment of autoimmune diseases. Here, we show the guanine nucleotide exchange factor, Tiam1, and its cognate Rho-family G protein, Rac1, regulate interleukin (IL)17A transcription and autoimmunity. Whereas Tiam1 genetic deficiency weakens IL-17A expression partially and inhibits the development of experimental autoimmune encephalomyelitis (EAE), deletion of Rac1 in T cells exhibits more robust effects on Th17 cells and EAE. We demonstrate Tiam1 and Rac1 form a complex with RORγt in the nuclear compartment of Th17 cells, and together bind and activate the Il17 promoter. The clinical relevance of these findings is emphasized by pharmacological targeting of Rac1 that suppresses both murine and human Th17 cells as well as EAE. Thus, our findings highlight a regulatory pathway of Tiam1/Rac1 in Th17 cells and suggest that it may be a therapeutic target in multiple sclerosis. PMID:27725632

  11. Tum/RacGAP functions as a switch activating the Pav/kinesin-6 motor

    PubMed Central

    Tao, Li; Fasulo, Barbara; Warecki, Brandt; Sullivan, William

    2016-01-01

    Centralspindlin is essential for central spindle and cleavage furrow formation. Drosophila centralspindlin consists of a kinesin-6 motor (Pav/kinesin-6) and a GTPase-activating protein (Tum/RacGAP). Centralspindlin localization to the central spindle is mediated by Pav/kinesin-6. While Tum/RacGAP has well-documented scaffolding functions, whether it influences Pav/kinesin-6 function is less well-explored. Here we demonstrate that both Pav/kinesin-6 and the centralspindlin complex (co-expressed Pav/Tum) have strong microtubule bundling activity. Centralspindlin also has robust plus-end-directed motility. In contrast, Pav/kinesin-6 alone cannot move microtubules. However, the addition of Tum/RacGAP or a 65 amino acid Tum/RacGAP fragment to Pav/kinesin-6 restores microtubule motility. Further, ATPase assays reveal that microtubule-stimulated ATPase activity of centralspindlin is seven times higher than that of Pav/kinesin-6. These findings are supported by in vivo studies demonstrating that in Tum/RacGAP-depleted S2 Drosophila cells, Pav/kinesin-6 exhibits severely reduced localization to the central spindle and an abnormal concentration at the centrosomes. PMID:27091402

  12. The Campylobacter jejuni RacRS system regulates fumarate utilization in a low oxygen environment.

    PubMed

    van der Stel, Anne-Xander; van Mourik, Andries; Heijmen-van Dijk, Linda; Parker, Craig T; Kelly, David J; van de Lest, Chris H A; van Putten, Jos P M; Wösten, Marc M S M

    2015-04-01

    The natural environment of the human pathogen Campylobacter jejuni is the gastrointestinal tract of warm-blooded animals. In the gut, the availability of oxygen is limited; therefore, less efficient electron acceptors such as nitrate or fumarate are used by C. jejuni. The molecular mechanisms that regulate the activity of the highly branched respiratory chain of C. jejuni are still a mystery mainly because C. jejuni lacks homologues of transcription factors known to regulate energy metabolism in other bacteria. Here we demonstrate that dependent on the available electron acceptors the two-component system RacRS controls the production of fumarate from aspartate, as well as its transport and reduction to succinate. Transcription profiling, DNAse protection and functional assays showed that phosphorylated RacR binds to and represses at least five promoter elements located in front of genes involved in the uptake and synthesis of fumarate. The RacRS system is active in the presence of nitrate and trimethyl-amine-N-oxide under oxygen-limited conditions when fumarate is less preferred as an alternative electron acceptor. In the inactive state, RacRS allows utilization of fumarate for respiration. The unique C. jejuni RacRS regulatory system illustrates the disparate evolution of Campylobacter and aids the survival of this pathogen.

  13. Cytotoxic Necrotizing Factor-Y Boosts Yersinia Effector Translocation by Activating Rac Protein*

    PubMed Central

    Wolters, Manuel; Boyle, Erin C.; Lardong, Kerstin; Trülzsch, Konrad; Steffen, Anika; Rottner, Klemens; Ruckdeschel, Klaus; Aepfelbacher, Martin

    2013-01-01

    Pathogenic Yersinia spp. translocate the effectors YopT, YopE, and YopO/YpkA into target cells to inactivate Rho family GTP-binding proteins and block immune responses. Some Yersinia spp. also secrete the Rho protein activator cytotoxic necrotizing factor-Y (CNF-Y), but it has been unclear how the bacteria may benefit from Rho protein activation. We show here that CNF-Y increases Yop translocation in Yersinia enterocolitica-infected cells up to 5-fold. CNF-Y strongly activated RhoA and also delayed in time Rac1 and Cdc42, but when individually expressed, constitutively active mutants of Rac1, but not of RhoA, increased Yop translocation. Consistently, knock-out or knockdown of Rac1 but not of RhoA, -B, or -C inhibited Yersinia effector translocation in CNF-Y-treated and control cells. Activation or knockdown of Cdc42 also affected Yop translocation but much less efficiently than Rac. The increase in Yop translocation induced by CNF-Y was essentially independent of the presence of YopE, YopT, or YopO in the infecting Yersinia strain, indicating that none of the Yops reported to inhibit translocation could reverse the CNF-Y effect. In summary, the CNF-Y activity of Yersinia strongly enhances Yop translocation through activation of Rac. PMID:23803609

  14. In Vitro Prenylation of the Small GTPase Rac13 of Cotton.

    PubMed Central

    Trainin, T.; Shmuel, M.; Delmer, D. P.

    1996-01-01

    Previous work (D.P. Delmer, J. Pear, A. Andrawis, D. Stalker [1995] Mol Gen Genet 248: 43-51) has identified a gene in cotton (Gossypium hirsutum), Rac13, that encodes a small, signal-transducing GTPase and shows high expression in the fiber at the time of transition from primary to secondary wall synthesis. Since Rac13 may be important in signal transduction pathway(s), regulating the onset of fiber secondary wall synthesis, we continue to characterize Rac13 by determining its ability to undergo posttranslational modification. In animals Rac proteins contain the C-terminal consensus sequence CaaL (where "a" can be any aliphatic residue), which is a site for geranylgeranylation (B.T. Kinsella, R.A. Erdman, W.A. Maltese [1994] J Biol Chem 266: 9786-9794). We have identified activities in developing cotton fibers that resemble in specificity the geranylgeranyl- and farnesyltransferases of animals and yeast. In addition, using prenyltransferases from rabbit reticulocytes, we show that Rac13, having a C-terminal sequence of CAFL, can serve as an in vitro substrate for geranylgeranylation but not farnesylation. However, the presence of the uncommon penultimate F residue appears to slow the rate of prenylation considerably compared with other acceptors. PMID:12226460

  15. Matrix compliance regulates Rac1b localization, NADPH oxidase assembly, and epithelial–mesenchymal transition

    PubMed Central

    Lee, KangAe; Chen, Qike K.; Lui, Cecillia; Cichon, Magdalena A.; Radisky, Derek C.; Nelson, Celeste M.

    2012-01-01

    Epithelial–mesenchymal transition (EMT) is a form of epithelial plasticity implicated in fibrosis and tumor metastasis. Here we show that the mechanical rigidity of the microenvironment plays a pivotal role in the promotion of EMT by controlling the subcellular localization and downstream signaling of Rac GTPases. Soft substrata, with compliances comparable to that of normal mammary tissue, are protective against EMT, whereas stiffer substrata, with compliances characteristic of breast tumors, promote EMT. Rac1b, a highly activated splice variant of Rac1 found in tumors, localizes to the plasma membrane in cells cultured on stiff substrata or in collagen-rich regions of human breast tumors. At the membrane, Rac1b forms a complex with NADPH oxidase and promotes the production of reactive oxygen species, expression of Snail, and activation of the EMT program. In contrast, soft microenvironments inhibit the membrane localization of Rac1b and subsequent redox changes. These results reveal a novel mechanotransduction pathway in the regulation of epithelial plasticity via EMT. PMID:22918955

  16. Building America Expert Meeting Report. Transitioning Traditional HVAC Contractors to Whole House Performance Contractors

    SciTech Connect

    Burdick, Arlan

    2011-10-01

    This expert meeting was hosted by the IBACOS Building America research team to determine how HVAC companies can transition from a traditional contractor status to a service provider for whole house energy upgrade contracting.

  17. Overexpression of WISP-1 down-regulated motility and invasion of lung cancer cells through inhibition of Rac activation.

    PubMed

    Soon, Lilian L; Yie, Ting-An; Shvarts, Anita; Levine, Arnold J; Su, Fei; Tchou-Wong, Kam-Meng

    2003-03-28

    Wnt-induced-secreted-protein-1 (WISP-1) is a cysteine-rich, secreted factor belonging to the CCN family. These proteins have been implicated in the inhibition of metastasis; however, the mechanisms involved have not been described. We demonstrated that overexpression of WISP-1 in H460 lung cancer cells inhibited lung metastasis and in vitro cell invasion and motility. We investigated the possibility that WISP-1 may regulate activation of Rac, a small GTPase important for cytoskeletal reorganizations during motility. In an indirect assay, WISP-1-expressing cells exhibited marked reduction in Rac activation compared with control cells. Blocking antibodies to alpha(v)beta(5) and alpha(1) integrins restored Rac activation in WISP-1 cells, suggesting that the inhibitory effect of WISP-1 on Rac lies downstream of integrins. Constitutively activated Rac mutant (RacG12V) was transfected into WISP-1 cells to restore Rac activation and these WISP-1/RacG12V transfectants were used for further studies. We performed microarray and real-time PCR analyses to identify genes involved in invasion that may be differentially regulated by WISP-1. Here, we showed decreased expression of metalloproteinase-1 (MMP-1) in WISP-1 cells compared with controls but increased expression in WISP-1/RacG12V cells. In an invasion assay across collagen I, an MMP-1 target matrix, WISP-1 cells were significantly less invasive compared with controls, whereas WISP-1/RacG12V cells showed elevated invasion levels. This work illustrates a negatively regulated pathway by WISP-1 involving integrins and Rac in the down-regulation of invasion.

  18. 48 CFR 45.606 - Contractor scrap procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CONTRACT MANAGEMENT GOVERNMENT PROPERTY Reporting, Reutilization, and Disposal 45.606 Contractor scrap procedures. (a) The property administrator should, in coordination with the plant clearance officer, ensure... proper disposition and are properly documented in the contractor's property management procedures....

  19. 48 CFR 645.608 - Screening of contractor inventory.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... inventory. 645.608 Section 645.608 Federal Acquisition Regulations System DEPARTMENT OF STATE CONTRACT MANAGEMENT GOVERNMENT PROPERTY Reporting, Redistribution, and Disposal of Contractor Inventory 645.608 Screening of contractor inventory....

  20. 48 CFR 2132.170 - Recurring premium payments to Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., a reconciliation of premiums, benefits, and other costs will be performed as a limited cost... Contractor's bank for payment. (c) Nothing in this chapter will affect the ability of the Contractor to...

  1. National radon contractor proficiency (RCP) program. Proficiency report, July 1993

    SciTech Connect

    Not Available

    1993-07-01

    The report will assist State, EPA Regions, and local government officials in providing advice to the public on the selection of proficient radon mitigation contractors. The Report is a listing of 853 contractors who have met the requirements of EPA's National Radon Contractor Proficiency (RCP) Program as of July 15, 1993. Each contractor is listed by name, RCP identification number, company name, address, phone number, and geographic service area.

  2. National Radon Contractor Proficiency (RCP) Program. Proficiency report

    SciTech Connect

    Not Available

    1990-07-01

    The report will assist State, EPA Regions, and local government officials in providing advice to the public on the selection of proficient radon mitigation contractors. The Proficiency Report is a listing of 895 contractors who have met the requirements of EPA's National Radon Contractor Proficiency (RCP) Program as of May 19, 1990. Each contractor is listed by name, RCP identification number, company name, address, phone number, and geographic service area.

  3. Exendin-4 alleviates angiotensin II-induced senescence in vascular smooth muscle cells by inhibiting Rac1 activation via a cAMP/PKA-dependent pathway.

    PubMed

    Zhao, Liang; Li, Ai Q; Zhou, Teng F; Zhang, Meng Q; Qin, Xiao M

    2014-12-15

    Vascular aging has been implicated in the progression of diabetes and age-related cardiovascular disorders. Glucagon-like peptide-1 (GLP-1) is an incretin hormone capable of cytoprotective actions in addition to its glucose-lowering effect. The present study was undertaken to examine whether Exendin-4, a specific ligand for the GLP-1 receptor, could prevent angiotensin (ANG) II-induced premature senescence in vascular smooth muscle cells (VSMCs) and to determine the underlying mechanism involved. Senescence-associated β-galactosidase (SA β-gal) assay showed that ANG II induced premature senescence of VSMCs. Pretreatment with Exendin-4 significantly attenuated ANG II-induced generation of H2O2 and the subsequent VSMC senescence. These effects were, however, reversed in the presence of exendin fragment 9-39, a GLP-1 receptor antagonist, or PKI14-22. Moreover, a marked increase in the levels of p53 and p21 induced by ANG II was blunted by the treatment with Exendin-4. Nevertheless, Exendin-4 failed to decrease ANG II-induced expression of NAD(P)H oxidase 1 (Nox1), NAD(P)H oxidase 4 (Nox4), p22(phox), or p47(phox) in VSMCs. Mechanistically, Exendin-4 blocked ANG II-induced Rac1 activation through the cAMP/PKA signaling cascade. Specifically, NSC23766, a Rac1 inhibitor, abrogated the suppressive effects of Exendin-4 on ANG II-induced premature senescence and H2O2 generation, respectively. Thus Exendin-4 confers resistance to ANG II-induced superoxide anion generation from NAD(P)H oxidase and the resultant VSMC senescence by inhibiting Rac1 activation via a cAMP/PKA-dependent pathway. These findings demonstrate that GLP-1 as well as its analogs (GLP-1-related reagents) may hold therapeutic potential in the treatment of diabetes with cardiovascular disease.

  4. The nuclear cofactor RAC3/AIB1/SRC-3 enhances Nrf2 signaling by interacting with transactivation domains

    PubMed Central

    Kim, Jung-Hwan; Yu, Siwang; Chen, J. Don; Kong, A.-N. Tony

    2012-01-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2, NM 006164, 605 AA) is essential for the antioxidant responsive element (ARE)-mediated expression of a group of detoxifying antioxidant genes that detoxify carcinogens and protect against oxidative stress. Several proteins have been identified as Nrf2-interacting molecules. In this study, we found that the overexpression of RAC3/AIB-1/SRC-3, a nuclear co-regulator and oncogene frequently amplified in human breast cancers, induced heme oxygenase-1 (HO-1) through Nrf2 transactivation in HeLa cells. Next, we determined the interaction between RAC3 and Nrf2 proteins using a co-immunoprecipitation assay (co-IP) and fluorescence resonance energy transfer (FRET) analysis. The results showed that RAC3 bound directly to the Nrf2 protein in the nucleus. Subsequently, we identified the interacting domains of Nrf2 and RAC3 using a GST pull-down assay. The results showed that both the N-terminal RAC3-pasB and C-terminal RAC3-R3B3 domains were tightly bound to the Neh4 and Neh5 transactivation domains. Furthermore, chromatin immunoprecipitation (ChIP) showed that RAC3 bound tightly to the ARE enhancer region of the HO-1 promoter via Nrf2 binding. These data suggest that Nrf2 activation is modulated and directly controlled through interactions with the RAC3 protein in HeLa cells. PMID:22370642

  5. Single-molecule tracking of small GTPase Rac1 uncovers spatial regulation of membrane translocation and mechanism for polarized signaling

    PubMed Central

    Das, Sulagna; Yin, Taofei; Yang, Qingfen; Zhang, Jingqiao; Wu, Yi I.; Yu, Ji

    2015-01-01

    Polarized Rac1 signaling is a hallmark of many cellular functions, including cell adhesion, motility, and cell division. The two steps of Rac1 activation are its translocation to the plasma membrane and the exchange of nucleotide from GDP to GTP. It is, however, unclear whether these two processes are regulated independent of each other and what their respective roles are in polarization of Rac1 signaling. We designed a single-particle tracking (SPT) method to quantitatively analyze the kinetics of Rac1 membrane translocation in living cells. We found that the rate of Rac1 translocation was significantly elevated in protrusions during cell spreading on collagen. Furthermore, combining FRET sensor imaging with SPT measurements in the same cell, the recruitment of Rac1 was found to be polarized to an extent similar to that of the nucleotide exchange process. Statistical analysis of single-molecule trajectories and optogenetic manipulation of membrane lipids revealed that Rac1 membrane translocation precedes nucleotide exchange, and is governed primarily by interactions with phospholipids, particularly PI(3,4,5)P3, instead of protein factors. Overall, the study highlights the significance of membrane translocation in spatial Rac1 signaling, which is in addition to the traditional view focusing primarily on GEF distribution and exchange reaction. PMID:25561548

  6. Characterization of a RacGTPase up-regulated in the large yellow croaker Pseudosciaena crocea immunity.

    PubMed

    Han, Fang; Wang, Xiaoqing; Yang, Qilian; Cai, Mingyi; Wang, Zhi Yong

    2011-02-01

    The Rac proteins are members of the Rho family of small G proteins and are implicated in the regulation of several pathways, including those leading to cytoskeleton reorganization, gene expression, cell proliferation, cell adhesion and cell migration and survival. In this investigation, a Rac gene (named as LycRac gene) was obtained from the large yellow croaker and it was expressed in Escherichia coli and purified. Subsequently the specific antibody was raised using the purified fusion protein (GST-LycRac). Moreover, the GTP-binding assay showed that the LycRac protein had GTP-binding activity. The LycRac gene was ubiquitously transcribed and expressed in 9 tissues. Quantitative real-time RT-PCR and Western blot analysis revealed the highest expression in gill and the weakest expression in spleen. Time-course analysis revealed that LycRac expression was obviously up-regulated in blood, spleen and liver after immunization with polyinosinic polycytidynic acid (poly I:C), formalin-inactive Gram-negative bacterium Vibrio parahemolyticus and bacterial lipopolysaccharides (LPS). These results suggested that LycRac protein might play an important role in the immune response against microorganisms in large yellow croaker. PMID:21130170

  7. Unraveling a novel Rac1-mediated signaling pathway that regulates cofilin dephosphorylation and secretion in thrombin-stimulated platelets.

    PubMed

    Pandey, Dharmendra; Goyal, Pankaj; Dwivedi, Suman; Siess, Wolfgang

    2009-07-01

    In platelets stimulated by thrombin to secrete and aggregate, cofilin is rapidly dephosphorylated leading to its activation. Cofilin by severing existing actin filaments and stimulating F-actin polymerization on newly created barbed ends dynamizes the actin cytoskeleton. We previously found that cofilin dephosphorylation is Ca(2+)-dependent and occurs upstream of degranulation in stimulated platelets. We report now in thrombin-stimulated platelets that Rac1 and class II PAKs (PAK4/5/6) were rapidly (within 5 seconds) activated, whereas PAK1/2 (class I PAKs) phosphorylation was slower. The Rac1-specific inhibitor NSC23766 blocked phosphorylation of class II PAKs, but not PAK1/2. Moreover, inhibition of the Ca(2+)/calmodulin-dependent phosphatase calcineurin inhibited Rac1 activation and class II PAKs phosphorylation. Prevention of Rac1 activation by calcineurin inhibition or NSC23766 also blocked cofilin dephosphorylation and platelet granule secretion indicating that a calcineurin/Rac1/class II PAKs pathway regulates cofilin dephosphorylation leading to secretion. We further found that PI3-kinases were activated downstream of Rac1, but were not involved in regulating cofilin dephosphorylation and secretion in thrombin-stimulated platelets. Our study unravels a Ca(2+)-dependent pathway of secretion in stimulated platelets as a signaling pathway linking Rac1 activation to actin dynamics: calcineurin-->Rac1-->class II PAKs-->cofilin activation. We further demonstrate that this pathway is separate and independent of the protein kinase C (PKC) pathway mediating secretion.

  8. TNF-alpha/cycloheximide-induced apoptosis in intestinal epithelial cells requires Rac1-regulated reactive oxygen species.

    PubMed

    Jin, Shi; Ray, Ramesh M; Johnson, Leonard R

    2008-04-01

    Previously we have shown that both Rac1 and c-Jun NH(2)-terminal kinase (JNK1/2) are key proapoptotic molecules in tumor necrosis factor (TNF)-alpha/cycloheximide (CHX)-induced apoptosis in intestinal epithelial cells, whereas the role of reactive oxygen species (ROS) in apoptosis is unclear. The present studies tested the hypothesis that Rac1-mediated ROS production is involved in TNF-alpha-induced apoptosis. In this study, we showed that TNF-alpha/CHX-induced ROS production and hydrogen peroxide (H(2)O(2))-induced oxidative stress increased apoptosis. Inhibition of Rac1 by a specific inhibitor NSC23766 prevented TNF-alpha-induced ROS production. The antioxidant, N-acetylcysteine (NAC), or rotenone (Rot), the mitochondrial electron transport chain inhibitor, attenuated mitochondrial ROS production and apoptosis. Rot also prevented JNK1/2 activation during apoptosis. Inhibition of Rac1 by expression of dominant negative Rac1 decreased TNF-alpha-induced mitochondrial ROS production. Moreover, TNF-alpha-induced cytosolic ROS production was inhibited by Rac1 inhibition, diphenyleneiodonium (DPI, an inhibitor of NADPH oxidase), and NAC. In addition, DPI inhibited TNF-alpha-induced apoptosis as judged by morphological changes, DNA fragmentation, and JNK1/2 activation. Mitochondrial membrane potential change is Rac1 or cytosolic ROS dependent. Lastly, all ROS inhibitors inhibited caspase-3 activity. Thus these results indicate that TNF-alpha-induced apoptosis requires Rac1-dependent ROS production in intestinal epithelial cells.

  9. 28 CFR 115.332 - Volunteer and contractor training.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Volunteer and contractor training. 115... ACT NATIONAL STANDARDS Standards for Juvenile Facilities Training and Education § 115.332 Volunteer and contractor training. (a) The agency shall ensure that all volunteers and contractors who...

  10. 28 CFR 115.332 - Volunteer and contractor training.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Volunteer and contractor training. 115... ACT NATIONAL STANDARDS Standards for Juvenile Facilities Training and Education § 115.332 Volunteer and contractor training. (a) The agency shall ensure that all volunteers and contractors who...

  11. 28 CFR 115.332 - Volunteer and contractor training.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Volunteer and contractor training. 115... ACT NATIONAL STANDARDS Standards for Juvenile Facilities Training and Education § 115.332 Volunteer and contractor training. (a) The agency shall ensure that all volunteers and contractors who...

  12. 48 CFR 252.242-7005 - Contractor business systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Contractor business... of Provisions And Clauses 252.242-7005 Contractor business systems. As prescribed in 242.7001, use the following clause: CONTRACTOR BUSINESS SYSTEMS (MAY 2011) (a) Definitions. As used in this...

  13. 48 CFR 1852.209-72 - Composition of the contractor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Composition of the contractor. 1852.209-72 Section 1852.209-72 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND... clause: Composition of the Contractor (DEC 1988) If the Contractor is comprised of more than one...

  14. 48 CFR 970.5244-1 - Contractor purchasing system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Contractor's participation in the conduct of the Balanced Scorecard performance measurement and performance... award of subcontracts consistent with this clause and 48 CFR subpart 970.44. The Contractor's purchasing... Energy (DOE) in accordance with 48 CFR 970.4401-1. The Contractor shall maintain file documentation...

  15. 77 FR 12754 - Contractor Legal Management Requirements; Acquisition Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-02

    ... Part 719 48 Parts 931, 952 and 970 RIN 1990-AA37 Contractor Legal Management Requirements; Acquisition... covering contractor legal management requirements and make conforming amendments to the Department of... rulemaking to revise existing regulations covering contractor legal management requirements and...

  16. 48 CFR 1052.210-70 - Contractor publicity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Contractor publicity. 1052.210-70 Section 1052.210-70 Federal Acquisition Regulations System DEPARTMENT OF THE TREASURY CLAUSES... Contractor publicity. As prescribed in 1009.204-70, insert the following clause: CONTRACTOR PUBLICITY...

  17. 20 CFR 655.19 - Job contractor filing requirements.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 3 2013-04-01 2013-04-01 false Job contractor filing requirements. 655.19... States (H-2B Workers) Application for Temporary Employment Certification Filing Procedures § 655.19 Job contractor filing requirements. (a) Provided that a job contractor and any employer-client are...

  18. 20 CFR 655.19 - Job contractor filing requirements.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Job contractor filing requirements. 655.19... States (H-2B Workers) Application for Temporary Employment Certification Filing Procedures § 655.19 Job contractor filing requirements. (a) Provided that a job contractor and any employer-client are...

  19. 20 CFR 655.19 - Job contractor filing requirements.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 3 2014-04-01 2014-04-01 false Job contractor filing requirements. 655.19... States (H-2B Workers) Application for Temporary Employment Certification Filing Procedures § 655.19 Job contractor filing requirements. (a) Provided that a job contractor and any employer-client are...

  20. 6 CFR 25.8 - Government contractor Defense.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 6 Domestic Security 1 2012-01-01 2012-01-01 false Government contractor Defense. 25.8 Section 25.8...-TERRORISM BY FOSTERING EFFECTIVE TECHNOLOGIES § 25.8 Government contractor Defense. (a) Criteria for... applicability of the government contractor defense. In determining whether to issue such Certification,...

  1. 32 CFR 516.21 - Litigation against government contractors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 3 2012-07-01 2009-07-01 true Litigation against government contractors. 516.21... government contractors. (a) General. A contract might require that the government reimburse a contractor (or... with the government requires reimbursement for adverse judgments or costs of the litigation, the SJA...

  2. 48 CFR 2452.251-70 - Contractor employee travel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor employee travel... 2452.251-70 Contractor employee travel. As prescribed in 2451.7001, insert the following clause in all cost-reimbursement solicitations and contracts involving travel: Contractor Employee Travel (OCT...

  3. 48 CFR 2452.251-70 - Contractor employee travel.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Contractor employee travel... 2452.251-70 Contractor employee travel. As prescribed in 2451.7001, insert the following clause in all cost-reimbursement solicitations and contracts involving travel: Contractor Employee Travel (OCT...

  4. 48 CFR 1852.209-72 - Composition of the contractor.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Composition of the... and Clauses 1852.209-72 Composition of the contractor. As prescribed in 1809.670, insert the following clause: Composition of the Contractor (DEC 1988) If the Contractor is comprised of more than one...

  5. 48 CFR 1852.209-72 - Composition of the contractor.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Composition of the... and Clauses 1852.209-72 Composition of the contractor. As prescribed in 1809.670, insert the following clause: Composition of the Contractor (DEC 1988) If the Contractor is comprised of more than one...

  6. 48 CFR 1852.209-72 - Composition of the contractor.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Composition of the... and Clauses 1852.209-72 Composition of the contractor. As prescribed in 1809.670, insert the following clause: Composition of the Contractor (DEC 1988) If the Contractor is comprised of more than one...

  7. 48 CFR 1852.209-72 - Composition of the contractor.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Composition of the... and Clauses 1852.209-72 Composition of the contractor. As prescribed in 1809.670, insert the following clause: Composition of the Contractor (DEC 1988) If the Contractor is comprised of more than one...

  8. 48 CFR 245.608 - Screening of contractor inventory.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Screening of contractor inventory. 245.608 Section 245.608 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS... Disposal of Contractor Inventory 245.608 Screening of contractor inventory....

  9. 32 CFR 516.21 - Litigation against government contractors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 3 2011-07-01 2009-07-01 true Litigation against government contractors. 516.21... government contractors. (a) General. A contract might require that the government reimburse a contractor (or... with the government requires reimbursement for adverse judgments or costs of the litigation, the SJA...

  10. 32 CFR 516.21 - Litigation against government contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Litigation against government contractors. 516.21... government contractors. (a) General. A contract might require that the government reimburse a contractor (or... with the government requires reimbursement for adverse judgments or costs of the litigation, the SJA...

  11. 6 CFR 25.8 - Government contractor Defense.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 6 Domestic Security 1 2013-01-01 2013-01-01 false Government contractor Defense. 25.8 Section 25.8...-TERRORISM BY FOSTERING EFFECTIVE TECHNOLOGIES § 25.8 Government contractor Defense. (a) Criteria for... applicability of the government contractor defense. In determining whether to issue such Certification,...

  12. 48 CFR 252.244-7001 - Contractor purchasing system administration.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Contractor purchasing... CLAUSES Text of Provisions And Clauses 252.244-7001 Contractor purchasing system administration. As prescribed in 244.305-71, insert the following clause: CONTRACTOR PURCHASING SYSTEM ADMINISTRATION (MAY...

  13. 41 CFR 60-1.31 - Reinstatement of ineligible contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Reinstatement of ineligible contractors. 60-1.31 Section 60-1.31 Public Contracts and Property Management Other Provisions... and Complaint Procedure § 60-1.31 Reinstatement of ineligible contractors. A contractor debarred...

  14. Testing of a Receiver-Absorber-Converter (RAC) for the Integrated Solar Upper Stage (ISUS) program

    NASA Astrophysics Data System (ADS)

    Westerman, Kurt O.; Miles, Barry J.

    1998-01-01

    The Integrated Solar Upper Stage (ISUS) is a solar bi-modal system based on a concept developed by Babcock & Wilcox in 1992. ISUS will provide advanced power and propulsion capabilities that will enable spacecraft designers to either increase the mass to orbit or decrease the cost to orbit for their satellites. In contrast to the current practice of using chemical propulsion for orbit transfer and photovoltaic conversion/battery storage for electrical power, ISUS uses a single collection, storage, and conversion system for both the power and propulsion functions. The ISUS system is currently being developed by the Air Force's Phillips Laboratory. The ISUS program consists of a systems analysis, design, and integration (SADI) effort, and three major sub-system development efforts: the Concentrator Array and Tracking (CATS) sub-system which tracks the sun and collects/focuses the energy; the Receiver-Absorber-Converter (RAC) sub-system which receives and stores the solar energy, transfers the stored energy to the propellant during propulsion operations, and converts the stored energy to electricity during power operations; and the Cryogenic Storage and Propellant Feed Sub-system (CSPFS) which stores the liquid hydrogen propellant and provides it to the RAC during propulsion operations. This paper discuses the evolution of the RAC sub-system as a result of the component level testing, and provides the initial results of systems level ground testing. A total of 5 RACs were manufactured as part of the Phillips Laboratory ISUS Technology Development program. The first series of component tests were carried out at the Solar Rocket Propulsion Laboratory at Edwards AFB, California. These tests provided key information on the propulsion mode of operations. The second series of RAC tests were performed at the Thermionic Evaluation Facility (TEF) in Albuquerque, New Mexico and provided information on the electrical performance of the RAC. The systems level testing was

  15. Cleavage of Hyaluronan and CD44 Adhesion Molecule Regulate Astrocyte Morphology via Rac1 Signalling

    PubMed Central

    Konopka, Anna; Zeug, Andre; Skupien, Anna; Kaza, Beata; Mueller, Franziska; Chwedorowicz, Agnieszka; Ponimaskin, Evgeni; Wilczynski, Grzegorz M.; Dzwonek, Joanna

    2016-01-01

    Communication of cells with their extracellular environment is crucial to fulfill their function in physiological and pathophysiological conditions. The literature data provide evidence that such a communication is also important in case of astrocytes. Mechanisms that contribute to the interaction between astrocytes and extracellular matrix (ECM) proteins are still poorly understood. Hyaluronan is the main component of ECM in the brain, where its major receptor protein CD44 is expressed by a subset of astrocytes. Considering the fact that functions of astrocytes are tightly coupled with changes in their morphology (e.g.: glutamate clearance in the synaptic cleft, migration, astrogliosis), we investigated the influence of hyaluronan cleavage by hyaluronidase, knockdown of CD44 by specific shRNA and CD44 overexpression on astrocyte morphology. Our results show that hyaluronidase treatment, as well as knockdown of CD44, in astrocytes result in a “stellate”-like morphology, whereas overexpression of CD44 causes an increase in cell body size and changes the shape of astrocytes into flattened cells. Moreover, as a dynamic reorganization of the actin cytoskeleton is supposed to be responsible for morphological changes of cells, and this reorganization is controlled by small GTPases of the Rho family, we hypothesized that GTPase Rac1 acts as a downstream effector for hyaluronan and CD44 in astrocytes. We used FRET-based biosensor and a dominant negative mutant of Rac1 to investigate the involvement of Rac1 activity in hyaluronidase- and CD44-dependent morphological changes of astrocytes. Both, hyaluronidase treatment and knockdown of CD44, enhances Rac1 activity while overexpression of CD44 reduces the activity state in astrocytes. Furthermore, morphological changes were blocked by specific inhibition of Rac1 activity. These findings indicate for the first time that regulation of Rac1 activity is responsible for hyaluronidase and CD44-driven morphological changes of

  16. Cyclooxygenase-2 knockdown using retinoic acid chalcone (RAC), a promising therapeutic strategy for colon cancer

    PubMed Central

    Jiang, Chao; Wang, Qiong; Xu, Zhe; Li, Wei-Su; Chen, Che; Yao, Xue-Quan; Liu, Fu-Kun

    2015-01-01

    Retinoic acid is an effective agent in the treatment of epithelial and hematological malignancies. The present study demonstrates that retinoic acid chalcone (RAC), an analogue of retinoic acid inhibits cell proliferation and induces apoptosis in HCT-15 and CT26.WT colon cancer cell lines. In HCT-15 cells the percentage of apoptotic cells increased from 32.4 ± 3, 45.0 ± 3 to 72.6 ± 5% respectively at 10, 15 and 20 μg/mL compared to 3.7% in control. Similarly in CT26.WT cells the percentage increased from 28.6 ± 3, 41.2 ± 3 to 65.4 ± 5% on treatment with 10, 15 and 20 μg/mL concentrations of RAC after 72 h compared to 2.9 ± 1% in control. Western blotting, fluorescence-activated cell sorting analysis and reverse transcription-PCR assays were used to investigate these effects. RAC inhibited the overexpression of COX-2, PGE2 and PGE2 receptor (EP1 and EP4) in the colon cancer cell lines. RAC mediated inhibition of cell growth and induction of apoptosis through COX-2 inhibition was also confirmed by treating the HCT-15 and CT26.WT colon cancer cells with COX-2 inhibitor, indomethacin and transfection of cells with COX-2 small interfering RNA. In nude mice with tumor xenografts, treatment with RAC-supplemented diet caused inhibition of COX-2, PGE2, and PGE2 receptors (EP1, EP3, and EP4) in tumors. Thus RAC can be a potential candidate for the treatment of colon cancer through the inhibition of COX-2 expression and subsequent inhibition of PGE2 and PGE2 receptors. PMID:26269760

  17. Prostaglandin E2-mediated migration of human trophoblast requires RAC1 and CDC42.

    PubMed

    Nicola, Catalin; Lala, Peeyush K; Chakraborty, Chandan

    2008-06-01

    The invasion of maternal decidua and uterine spiral arteries by a trophoblast subpopulation called extravillous trophoblast (EVT) is essential for the establishment of a normal placenta and an adequate blood flow toward the fetus. Derangements in these processes underlie pregnancy-related diseases like preeclampsia and intrauterine growth restriction. Many growth factors, growth factor binding proteins, and extracellular matrix components can positively or negatively regulate the proliferation, migration, and/or invasiveness of these EVT cells. RHO GTPases, including RHOA, RAC1, and CDC42, are ubiquitous proteins that control cytoskeletal changes by forming stress fibers and projecting lamellipodia and filopodia during cellular migration. We had previously shown that prostaglandin (PG) E(2) produced in abundance by the decidua promotes the migration of first-trimester human EVTs by increasing the intracellular concentration of calcium and activating calpain. Using our well-characterized immortalized EVT cell line, HTR-8/SVneo, as well as villus explants from first-trimester placentae, this study examined the role of RHO GTPases RAC1 and CDC42 in PGE(2)-mediated migratory responses of these cells. Though a RAC1 inhibitor, NSC23766 as well as RAC1 knockdown by siRNA decreased the migration of HTR-8/SVneo cells in a Transwell migration assay, this inhibition could not be restored by PGE(2) or 17-phenyl trinor PGE(2) (PGE receptor PTGER1 agonist) or PGE(1) Alcohol (PGE receptor PTGER4 agonist). Similar results were noted for EVT cell spreading in villus explants. Furthermore, CDC42 silencing using siRNA inhibited PGE(2)-induced migration of HTR-8/SVneo cells. Finally, the treatment of EVT cells with PGE(2), PTGER1 agonist, or PTGER4 agonist activated RAC1 and CDC42 at 10 min, suggesting that RAC1 and CDC42 play an essential role in PGE(2)-mediated migration of human EVTs.

  18. Contractor-style tunnel cost estimating

    SciTech Connect

    Scapuzzi, D. )

    1990-06-01

    Keeping pace with recent advances in construction technology is a challenge for the cost estimating engineer. Using an estimating style that simulates the actual construction process and is similar in style to the contractor's estimate will give a realistic view of underground construction costs. For a contractor-style estimate, a mining method is chosen; labor crews, plant and equipment are selected, and advance rates are calculated for the various phases of work which are used to determine the length of time necessary to complete each phase of work. The durations are multiplied by the cost or labor and equipment per unit of time and, along with the costs for materials and supplies, combine to complete the estimate. Variations in advance rates, ground support, labor crew size, or other areas are more easily analyzed for their overall effect on the cost and schedule of a project. 14 figs.

  19. Rac1 Controls Both the Secretory Function of the Mammary Gland and Its Remodeling for Successive Gestations.

    PubMed

    Akhtar, Nasreen; Li, Weiping; Mironov, Aleksander; Streuli, Charles H

    2016-09-12

    An important feature of the mammary gland is its ability to undergo repeated morphological changes during each reproductive cycle with profound tissue expansion in pregnancy and regression in involution. However, the mechanisms that determine the tissue's cyclic regenerative capacity remain elusive. We have now discovered that Cre-Lox ablation of Rac1 in mammary epithelia causes gross enlargement of the epithelial tree and defective alveolar regeneration in a second pregnancy. Architectural defects arise because loss of Rac1 disrupts clearance in involution following the first lactation. We show that Rac1 is crucial for mammary alveolar epithelia to switch from secretion to a phagocytic mode and rapidly remove dying neighbors. Moreover, Rac1 restricts the extrusion of dying cells into the lumen, thus promoting their eradication by live phagocytic neighbors while within the epithelium. Without Rac1, residual milk and cell corpses flood the ductal network, causing gross dilation, chronic inflammation, and defective future regeneration. PMID:27623383

  20. Needs of Non-Energy Focused Contractors

    SciTech Connect

    Liakus, C.

    2012-12-01

    To better understand the informational needs of non-energy focused contractors, including what information they need to motivate them to become energy-focused, the BARA team studied the type of information provided by the national programs, trade associations, and manufacturers that were researched for the related technical report: Effective Communication of Energy Efficiency. While that report focused on the delivery method, format, and strategy of the information, this study examines the content being put forward.

  1. Needs of Non Energy-Focused Contractors

    SciTech Connect

    Liaukus, C.

    2012-12-01

    To better understand the informational needs of non energy-focused contractors, including what information they need to motivate them to become energy-focused, the BARA team studied the type of information provided by the national programs, trade associations, and manufacturers that were researched for the related technical report: Effective Communication of Energy Efficiency. While that report focused on the delivery method, format, and strategy of the information, this study examines the content being put forward.

  2. Rac-1 as a new therapeutic target in cerebro- and cardio-vascular diseases.

    PubMed

    Carrizzo, Albino; Forte, Maurizio; Lembo, Maria; Formisano, Luigi; Puca, Annibale A; Vecchione, Carmine

    2014-01-01

    Growing evidence indicates that overproduction of reactive oxygen species (ROS) plays a prominent role in the development of cardio- and cerebro-vascular diseases. Among the mechanisms identified to produce oxidative stress in the vascular wall, those mediated by membrane-bound NAD(P)H oxidases represent a major one. NAD(P)H oxidases are a family of enzymes that generate ROS both in phagocytic and non-phagocytic cell types. Vascular NAD(P)H oxidase contains the membrane-bound subunits Nox1, Nox2 (gp91phox), Nox4 and p22phox, the catalytic site of the oxidase, and the cytosolic components p47phox and p67phox. Rac1 (Ras-related C3 botulinum toxin substrate1) is a small GTPase essential for the assembly and activation of NADPH oxidase. Several molecular and cellular studies have reported the involvement of Rac1 in different cardiovascular pathologies, such as vascular smooth muscle proliferation, cardiomyocyte hypertrophy, endothelial cell shape change, atherosclerosis and endothelial dysfunction in hypertension. In addition, increased activation of NADPH oxidase by Rac1 has been reported in animals and humans after myocardial infarction and heart failure. The Rac1/NADPH pathway has also been found involved in different pathologies of the cerebral district, such as ischemic stroke, cognitive impairment, subaracnoid hemorrhage and neuronal oxidative damage typical of several neurodegenerative disorders. In addition, thrombotic events are an important step in the onset of cardio- and cerebrovascular diseases. Rac1 has been found involved also in platelet activation, inducing actin polymerization and lamellipodia formation, which are necessary steps for platelet aggregation. Taken together, the evidence candidates Rac1 as a new pharmacological target of cardiovascular and cerebrovascular diseases. Although the involvement of Rac1 in the beneficial pleiotropic effects of drugs such as statins is well known, and the onset of numerous side effects has raised concern for the

  3. Rac1 is required for Prkar1a-mediated Nf2 suppression in Schwann cell tumors.

    PubMed

    Manchanda, P K; Jones, G N; Lee, A A; Pringle, D R; Zhang, M; Yu, L; La Perle, K M D; Kirschner, L S

    2013-07-25

    Schwannomas are peripheral nerve sheath tumors that often occur in the setting of an inherited tumor predisposition syndrome, including neurofibromatosis types 1 (NF1) and 2 (NF2), familial schwannomatosis and Carney complex. Loss of the NF2 tumor suppressor (encoding NF2, or Merlin) is associated with upregulation of the Rac1 small GTPase, which is thought to have a key role in mediating tumor formation. In prior studies, we generated a mouse model of schwannomas by performing tissue-specific knockout (KO) of the Carney complex gene Prkar1a, which encodes the type 1A regulatory subunit of protein kinase A. These tumors exhibited down-regulation of Nf2 protein and an increase in activated Rac1. To assess the requirement for Rac1 in schwannoma formation, we generated a double KO (DKO) of Prkar1a and Rac1 in Schwann cells and monitored tumor formation. Loss of Rac1 reduced tumor formation by reducing proliferation and enhancing apoptosis. Surprisingly, the reduction of tumor formation was accompanied by re-expression of the Nf2 protein. Furthermore, activated Rac1 was able to downregulate Nf2 in vitro in a Pak-dependent manner. These in vivo data indicate that activation of Rac1 is responsible for suppression of Nf2 protein production; deficiency of Nf2 in Schwann cells leads to loss of cellular growth control and tumor formation. Further, PKA activation through mutation in Prkar1a is sufficient to initiate Rac1 signaling, with subsequent reduction of Nf2 and schwannomagenesis. Although in vitro evidence has shown that loss of Nf2 activates Rac1, our data indicate that signaling between Nf2 and Rac1 occurs in a bidirectional fashion, and these interactions are modulated by PKA. PMID:23045281

  4. Rac1 is required for Prkar1a-mediated Nf2 suppression in Schwann cell tumors

    PubMed Central

    Manchanda, Parmeet K.; Jones, Georgette N.; Lee, Audrey A.; Pringle, Daphne R.; Zhang, Mei; Yu, Lianbo; La Perle, Krista M. D.; Kirschner, Lawrence S.

    2012-01-01

    Schwannomas are peripheral nerve sheath tumors that often occur in the setting of an inherited tumor predisposition syndrome, including Neurofibromatosis Types 1 (NF1) and 2 (NF2), Familial Schwannomatosis (FS) and Carney Complex (CNC). Loss of the NF2 tumor suppressor (encoding NF2, or Merlin) is associated with upregulation of the Rac1 small GTPase, which is thought to play a key role in mediating tumor formation. In prior studies, we generated a mouse model of schwannomas by performing tissue-specific knockout of the CNC gene Prkar1a, which encodes the type 1A regulatory subunit of Protein Kinase A. These tumors exhibited down-regulation of Nf2 protein and an increase in activated Rac1. To assess the requirement for Rac1 in schwannoma formation, we generated a double knockout of Prkar1a and Rac1 in Schwann cells and monitored tumor formation. Loss of Rac1 reduced tumor formation by reducing proliferation and enhancing apoptosis. Surprisingly, the reduction of tumor formation was accompanied by re-expression of the Nf2 protein. Furthermore, activated Rac1 was able to downregulate Nf2 in vitro in a Pak-dependent manner. These in vivo data indicate that activation of Rac1 is responsible for suppression of Nf2 protein production; deficiency of Nf2 in Schwann cells leads to loss of cellular growth control and tumor formation.. Further, PKA activation through mutation in Prkar1a is sufficient to initiate Rac1 signaling, with subsequent reduction of Nf2 and schwannomagenesis. Although in vitro evidence has shown that loss of Nf2 activates Rac1, our data indicates that signaling between Nf2 and Rac1 occurs in a bidirectional fashion, and these interactions are modulated by PKA. PMID:23045281

  5. Selective Rac1 inhibition protects renal tubular epithelial cells from oxalate-induced NADPH oxidase-mediated oxidative cell injury.

    PubMed

    Thamilselvan, Vijayalakshmi; Menon, Mani; Thamilselvan, Sivagnanam

    2012-08-01

    Oxalate-induced oxidative cell injury is one of the major mechanisms implicated in calcium oxalate nucleation, aggregation and growth of kidney stones. We previously demonstrated that oxalate-induced NADPH oxidase-derived free radicals play a significant role in renal injury. Since NADPH oxidase activation requires several regulatory proteins, the primary goal of this study was to characterize the role of Rac GTPase in oxalate-induced NADPH oxidase-mediated oxidative injury in renal epithelial cells. Our results show that oxalate significantly increased membrane translocation of Rac1 and NADPH oxidase activity of renal epithelial cells in a time-dependent manner. We found that NSC23766, a selective inhibitor of Rac1, blocked oxalate-induced membrane translocation of Rac1 and NADPH oxidase activity. In the absence of Rac1 inhibitor, oxalate exposure significantly increased hydrogen peroxide formation and LDH release in renal epithelial cells. In contrast, Rac1 inhibitor pretreatment, significantly decreased oxalate-induced hydrogen peroxide production and LDH release. Furthermore, PKC α and δ inhibitor, oxalate exposure did not increase Rac1 protein translocation, suggesting that PKC resides upstream from Rac1 in the pathway that regulates NADPH oxidase. In conclusion, our data demonstrate for the first time that Rac1-dependent activation of NADPH oxidase might be a crucial mechanism responsible for oxalate-induced oxidative renal cell injury. These findings suggest that Rac1 signaling plays a key role in oxalate-induced renal injury, and may serve as a potential therapeutic target to prevent calcium oxalate crystal deposition in stone formers and reduce recurrence.

  6. Building America Expert Meeting Report: Transitioning Traditional HVAC Contractors to Whole House Performance Contractors

    SciTech Connect

    Burdick, A.

    2011-10-01

    This report outlines findings resulting from a U.S. Department of Energy Building America expert meeting to determine how HVAC companies can transition from a traditional contractor status to a service provider for whole house energy upgrade contracting. IBACOS has embarked upon a research effort under the Building America Program to understand business impacts and change management strategies for HVAC companies. HVAC companies can implement these strategies in order to quickly transition from a 'traditional' heating and cooling contractor to a service provider for whole house energy upgrade contracting. Due to HVAC service contracts, which allow repeat interaction with homeowners, HVAC companies are ideally positioned in the marketplace to resolve homeowner comfort issues through whole house energy upgrades. There are essentially two primary ways to define the routes of transition for an HVAC contractor taking on whole house performance contracting: (1) Sub-contracting out the shell repair/upgrade work; and (2) Integrating the shell repair/upgrade work into their existing business. IBACOS held an Expert Meeting on the topic of Transitioning Traditional HVAC Contractors to Whole House Performance Contractors on March 29, 2011 in San Francisco, CA. The major objectives of the meeting were to: Review and validate the general business models for traditional HVAC companies and whole house energy upgrade companies Review preliminary findings on the differences between the structure of traditional HVAC Companies and whole house energy upgrade companies Seek industry input on how to structure information so it is relevant and useful for traditional HVAC contractors who are transitioning to becoming whole house energy upgrade contractors Seven industry experts identified by IBACOS participated in the session along with one representative from the National Renewable Energy Laboratory (NREL). The objective of the meeting was to validate the general operational profile of an

  7. All-rac-alpha-tocopherol acetate is a better vitamin E source than all-rac-alpha-tocopherol succinate for broilers.

    PubMed

    Jensen, S K; Engberg, R M; Hedemann, M S

    1999-07-01

    The difference in bioavailabilities of the acetate and succinate esters of all-rac-alpha-tocopherol was investigated in a feeding experiment with broilers. The experiment was initiated with 96 12-d-old male Cobb broilers and lasted for 4 wk. The two sources of vitamin E were fed to eight groups of broilers at four different dietary levels (50, 100, 150 and 200 mg/kg feed, including the naturally occurring alpha-tocopherol). A total collection of droppings for determination of apparent tocopherol absorption were performed at two separate time periods (d 28-34 and d 35-41). There were no differences among the eight experimental groups with respect to animal performance or feed intake. At all dietary levels, the apparent absorption coefficient for all-rac-alpha-tocopherol succinate was significantly lower than that of the acetate ester. The mean (+/- SD) apparent absorption coefficient for all-rac-alpha-tocopherol succinate was 58.0 +/- 5.4 compared with 70. 8 +/- 5.6 for all-rac-alpha-tocopherol acetate. Furthermore, the apparent absorption coefficients for both esters was significantly lower in the first collection period (d 28-34) than in the second collection period (d 35-41). This difference in the apparent absorption coefficient between the succinate and the acetate ester was accompanied by significant differences in alpha-tocopherol concentrations in plasma, breast muscle, liver and adipose tissue of the broilers, which were lower in those fed the succinate ester. Based on a comparison of plasma and tissue responses, the succinate ester was utilized only 69-76% as efficiently as the acetate ester. In vitro studies showed a significantly higher capacity of pancreatic carboxyl ester hydrolase to hydrolyze alpha-tocopherol acetate compared to alpha-tocopherol succinate. This difference in intestinal hydrolysis of the two vitamin E sources may explain the observed differences in biopotency.

  8. 42 CFR 421.316 - Limitation on Medicare integrity program contractor liability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Contractors § 421.316 Limitation on Medicare integrity program contractor liability. (a) A MIP contractor, a... services to a MIP contractor is not in violation of any criminal law or civilly liable under any law of...

  9. 42 CFR 421.316 - Limitation on Medicare integrity program contractor liability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Contractors § 421.316 Limitation on Medicare integrity program contractor liability. (a) A MIP contractor, a... services to a MIP contractor is not in violation of any criminal law or civilly liable under any law of...

  10. 77 FR 14490 - Defense Federal Acquisition Regulation Supplement: Alleged Crimes By or Against Contractor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-12

    ... Regulation Supplement: Alleged Crimes By or Against Contractor Personnel (DFARS Case 2012-D006) AGENCY... coverage on contractor requirements and responsibilities relating to alleged crimes by or against... contractor requirements and responsibilities regarding alleged crimes by or against contractor personnel....

  11. Final Report: Contractor Readiness Assessment (CRA) for TREAT Fuel Movement and Control Rod Drives Isolation

    SciTech Connect

    Rowsell, David Leon

    2015-06-01

    This report documents the Contractor Readiness Assessment (CRA) for TREAT Fuel Movement and Control Rod Drives Isolation. The review followed the approved Plan of Action (POA) and Implementation Plan (IP) using the identified core requirements. The activity was limited scope focusing on the control rod drives functional isolation and fuel element movement. The purpose of this review is to ensure the facility's readiness to move fuel elements thus supporting inspection and functionally isolate the control rod drives to maintain the required shutdown margin.

  12. rac p21 is involved in insulin-induced membrane ruffling and rho p21 is involved in hepatocyte growth factor- and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced membrane ruffling in KB cells.

    PubMed Central

    Nishiyama, T; Sasaki, T; Takaishi, K; Kato, M; Yaku, H; Araki, K; Matsuura, Y; Takai, Y

    1994-01-01

    Insulin and hepatocyte growth factor (HGF) induced morphologically different membrane rufflings in KB cells. Insulin-induced membrane ruffling was inhibited by microinjection of rho GDI, an inhibitory GDP/GTP exchange regulator for both rho p21 and rac p21 small GTP-binding proteins, but not inhibited by microinjection of botulinum exoenzyme C3, known to selectively ADP-ribosylate rho p21 and to impair its function. This rho GDI action was prevented by comicroinjection with guanosine 5'-(3-O-thio)triphosphate (GTP gamma S)-bound rac1 p21. In contrast, HGF-induced membrane ruffling was inhibited by microinjection of rho GDI or C3. This rho GDI action was prevented by comicroinjection with GTP gamma S-bound rhoA p21, and this C3 action was prevented by comicroinjection with GTP gamma S-bound rhoAIle-41 p21, which is resistant to C3. Microinjection of either GTP gamma S-bound rac1 p21 or rhoA p21 alone induced membrane ruffling in the absence of the growth factors. The rac1 p21-induced membrane ruffling was morphologically similar to the insulin-induced kind, whereas rhoA p21-induced ruffling was apparently different from both the insulin- and HGF-induced kinds. Membrane ruffling was also induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C-activating phorbol ester, but not by Ca2+ ionophore or microinjection of a dominant active Ki-ras p21 mutant (Ki-rasVal-12 p21). The phorbol ester-induced membrane ruffling was morphologically similar to the rhoA p21-induced kind and inhibited by microinjection of rho GDI or C3. These results indicate that rac p21 and rho GDI are involved in insulin-induced membrane ruffling and that rho p21 and rho GDI are involved in HGF- and phorbol ester-induced membrane rufflings. Images PMID:8139548

  13. 41 CFR 60-250.43 - Affirmative action policy.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Affirmative action policy... OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS... PROTECTED VETERANS Affirmative Action Program § 60-250.43 Affirmative action policy. Under the...

  14. 41 CFR 60-4.4 - Affirmative action requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Affirmative action... OF LABOR 4-CONSTRUCTION CONTRACTORS-AFFIRMATIVE ACTION REQUIREMENTS § 60-4.4 Affirmative action requirements. (a) To implement the affirmative action requirements of Executive Order 11246 in the...

  15. 41 CFR 60-4.4 - Affirmative action requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Affirmative action... OF LABOR 4-CONSTRUCTION CONTRACTORS-AFFIRMATIVE ACTION REQUIREMENTS § 60-4.4 Affirmative action requirements. (a) To implement the affirmative action requirements of Executive Order 11246 in the...

  16. 41 CFR 60-741.43 - Affirmative action policy.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Affirmative action... OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS REGARDING INDIVIDUALS WITH DISABILITIES Affirmative Action Program § 60-741.43 Affirmative action...

  17. 41 CFR 60-741.43 - Affirmative action policy.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Affirmative action policy... OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS REGARDING INDIVIDUALS WITH DISABILITIES Affirmative Action Program § 60-741.43 Affirmative action...

  18. 41 CFR 60-250.43 - Affirmative action policy.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Affirmative action policy... OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS... PROTECTED VETERANS Affirmative Action Program § 60-250.43 Affirmative action policy. Under the...

  19. 41 CFR 60-300.43 - Affirmative action policy.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Affirmative action policy... OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS... MEDAL VETERANS Affirmative Action Program § 60-300.43 Affirmative action policy. Under the...

  20. 41 CFR 60-300.43 - Affirmative action policy.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Affirmative action policy... OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS... MEDAL VETERANS Affirmative Action Program § 60-300.43 Affirmative action policy. Under the...

  1. 41 CFR 60-4.4 - Affirmative action requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Affirmative action... OF LABOR 4-CONSTRUCTION CONTRACTORS-AFFIRMATIVE ACTION REQUIREMENTS § 60-4.4 Affirmative action requirements. (a) To implement the affirmative action requirements of Executive Order 11246 in the...

  2. 41 CFR 60-4.4 - Affirmative action requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Affirmative action... OF LABOR 4-CONSTRUCTION CONTRACTORS-AFFIRMATIVE ACTION REQUIREMENTS § 60-4.4 Affirmative action requirements. (a) To implement the affirmative action requirements of Executive Order 11246 in the...

  3. 41 CFR 60-300.43 - Affirmative action policy.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Affirmative action... OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS... MEDAL VETERANS Affirmative Action Program § 60-300.43 Affirmative action policy. Under the...

  4. 41 CFR 60-4.4 - Affirmative action requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Affirmative action... OF LABOR 4-CONSTRUCTION CONTRACTORS-AFFIRMATIVE ACTION REQUIREMENTS § 60-4.4 Affirmative action requirements. (a) To implement the affirmative action requirements of Executive Order 11246 in the...

  5. 41 CFR 60-741.43 - Affirmative action policy.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Affirmative action policy... OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS REGARDING INDIVIDUALS WITH DISABILITIES Affirmative Action Program § 60-741.43 Affirmative action...

  6. 41 CFR 60-250.43 - Affirmative action policy.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Affirmative action... OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS... PROTECTED VETERANS Affirmative Action Program § 60-250.43 Affirmative action policy. Under the...

  7. 44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Functions of a Regional Assistance Committee (RAC). 352.23 Section 352.23 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS COMMERCIAL NUCLEAR POWER PLANTS:...

  8. Osteopontin-Rac1 on Blood-Brain Barrier Stability Following Rodent Neonatal Hypoxia-Ischemia.

    PubMed

    Dixon, Brandon; Malaguit, Jay; Casel, Darlene; Doycheva, Desislava; Tang, Jiping; Zhang, John H; Lekic, Tim

    2016-01-01

    Osteopontin (OPN) is a neuroprotective molecule that is upregulated following rodent neonatal hypoxic-ischemic (nHI) brain injury. Because Rac1 is a regulator of blood-brain barrier (BBB) stability, we hypothesized a role for this in OPN signaling. nHI was induced by unilateral ligation of the right carotid artery followed by hypoxia (8 % oxygen for 2 h) in P10 Sprague-Dawley rat pups. Intranasal (iN) OPN was administered at 1 h post-nHI. Groups consisted of: (1) Sham, (2) Vehicle, (3) OPN, and (4) OPN + Rac1 inhibitor (NSC23766). Evans blue dye extravasation (BBB permeability) was quantified 24 h post-nHI, and brain edema at 48 h. Increased BBB permeability and brain edema following nHI was ameliorated in the OPN treatment group. However, those rat pups receiving OPN co-treatment with the Rac1 inhibitor experienced no improvement compared with vehicle. OPN protects the BBB following nHI, and this was reversed by Rac1 inhibitor (NSC23766). PMID:26463959

  9. Antiviral activity of a Rac GEF inhibitor characterized with a sensitive HIV/SIV fusion assay

    SciTech Connect

    Pontow, Suzanne; Harmon, Brooke; Campbell, Nancy; Ratner, Lee

    2007-11-10

    A virus-dependent fusion assay was utilized to examine the activity of a panel of HIV-1, -2, and SIV isolates of distinct coreceptor phenotypes. This assay allowed identification of entry inhibitors, and characterization of an antagonist of a Rac guanine nucleotide exchange factor, as an inhibitor of HIV-mediated fusion.

  10. Structural details of light activation of the LOV2-based photoswitch PA-Rac1.

    PubMed

    Winkler, Andreas; Barends, Thomas R M; Udvarhelyi, Anikó; Lenherr-Frey, Daniel; Lomb, Lukas; Menzel, Andreas; Schlichting, Ilme

    2015-02-20

    Optical control of cellular processes is an emerging approach for studying biological systems, affording control with high spatial and temporal resolution. Specifically designed artificial photoswitches add an interesting extension to naturally occurring light-regulated functionalities. However, despite a great deal of structural information, the generation of new tools cannot be based fully on rational design yet; in many cases design is limited by our understanding of molecular details of light activation and signal transduction. Our biochemical and biophysical studies on the established optogenetic tool PA-Rac1, the photoactivatable small GTPase Rac1, reveal how unexpected details of the sensor-effector interface, such as metal coordination, significantly affect functionally important structural elements of this photoswitch. Together with solution scattering experiments, our results favor differences in the population of pre-existing conformations as the underlying allosteric activation mechanism of PA-Rac1, rather than the assumed release of the Rac1 domain from the caging photoreceptor domain. These results have implications for the design of new optogenetic tools and highlight the importance of including molecular details of the sensor-effector interface, which is however difficult to assess during the initial design of novel artificial photoswitches.

  11. Responsible Adult Culture (RAC): Cognitive and Behavioral Changes at a Community-Based Correctional Facility

    ERIC Educational Resources Information Center

    Devlin, Renee S.; Gibbs, John C.

    2010-01-01

    This article examined cognitive and behavioral changes among participants in Responsible Adult Culture (RAC), a cognitive-behavioral (especially, cognitive restructuring) treatment program in use at the Franklin County Community-Based Correctional Facility (CBCF). Participants were adult felony offenders (approximately three-fourths male). A…

  12. 44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS COMMERCIAL NUCLEAR POWER PLANTS: EMERGENCY.... (b) Prior to a determination under subpart A (44 CFR 352.6(d)) that Federal facilities and resources... under subpart A (44 CFR 352.6(d)) that Federal facilities and resources are needed, the RAC will...

  13. Comparative effect of lidocaine, bupivacaine and RAC 109 on myocardial conduction and contractility in the rabbit.

    PubMed

    Kariya, Nobutaka; Cosson, Claudine; Mazoit, Jean-Xavier

    2012-09-15

    Local anesthetic toxicity includes a decrease in ventricular conduction velocity and a decrease in myocardial contractile force. We tested the hypothesis that, like conduction, contraction was stereoselectively impaired by bupivacaine. We compared R(+) and S(-) bupivacaine to S(+) and R(-) RAC 109 in order to study the effects of hydrophobicity and ionization. We measured the changes in QRS duration and developed pressure in isolated perfused rabbit hearts. Binding of bupivacaine and RAC 109 to the ryanodine receptor was measured. The effect on cell shortening and relenghtening was measured on isolated rabbit cardiomyocytes. A mixed-effect pharmacodynamic model was used. The decrease in conduction velocity induced by the molecules was markedly stereospecific. All local anesthetics decreased ventricular velocity in a stereospecific manner with a RAC I(+)/II(-) and bupivacaine R(+)/S(-) potency ratio of maximum effect of 1.7 and 2.25 respectively. Contractility decreased in a dose dependent manner but this negative inotropic effect was not stereospecific with a C50 (concentration leading to half maximum effect) of 30 and 23 μM for RAC and bupivacaine respectively. The two drugs exhibited two-site binding to ryanodyne that may partly explain the observed effect. An effect on relaxation was observed only at very high concentrations. In conclusion, bupivacaine, a long acting local anesthetic, decreases ventricular conduction in a stereospecific manner, and decreases contractility non-stereospecifically.

  14. A FAK-Cas-Rac-Lamellipodin Signaling Module Transduces Extracellular Matrix Stiffness into Mechanosensitive Cell Cycling

    PubMed Central

    Bae, Yong Ho; Mui, Keeley L.; Hsu, Bernadette Y.; Liu, Shu-Lin; Cretu, Alexandra; Razinia, Ziba; Xu, Tina; Puré, Ellen; Assoian, Richard K.

    2015-01-01

    Tissue and extracellular matrix (ECM) stiffness is transduced into intracellular stiffness, signaling, and changes in cellular behavior. Integrins and several of their associated focal adhesion proteins have been implicated in sensing ECM stiffness. We investigated how an initial sensing event is translated into intracellular stiffness and a biologically interpretable signal. We found that a pathway consisting of focal adhesion kinase (FAK), the adaptor protein p130Cas (Cas), and the guanosine triphosphatase Rac selectively transduced ECM stiffness into stable intracellular stiffness, increased abundance of the cell cycle protein cyclin D1, and promoted S phase entry. Rac-dependent intracellular stiffening involved its binding partner lamellipodin, a protein that transmits Rac signals to the cytoskeleton during cell migration. Our findings establish that mechanotransduction by a FAK-Cas-Rac-lamellipodin signaling module converts the external information encoded by ECM stiffness into stable intracellular stiffness and mechanosensitive cell cycling. Thus, lamellipodin is not only important in controlling cellular migration, but also for regulating the cell cycle in response to mechanical signals. PMID:24939893

  15. Fibroblastic Transformation of Corneal Keratocytes by Rac Inhibition is Modulated by Extracellular Matrix Structure and Stiffness

    PubMed Central

    Petroll, W. Matthew; Lakshman, Neema

    2015-01-01

    The goal of this study was to investigate how alterations in extracellular matrix (ECM) biophysical properties modulate corneal keratocyte phenotypes in response to specific wound healing cytokines and Rho GTPases. Rabbit corneal keratocytes were plated within standard collagen matrices (2.5 mg/mL) or compressed collagen matrices (~100 mg/mL) and cultured in serum-free media, PDGF BB, IGF, FGF2 or TGFβ1, with or without the Rac1 inhibitor NSC23766 and/or the Rho kinase inhibitor Y-27632. After 1 to 4 days, cells were labeled for F-actin and imaged using confocal microscopy. Keratocytes within standard collagen matrices (which are highly compliant) maintained a dendritic phenotype following culture in serum-free media, PDGF, IGF and FGF, but developed stress fibers in TGFβ1. Keratocytes within compressed collagen (which has high stiffness and low porosity) maintained a dendritic phenotype following culture in serum-free media, PDGF and IGF, but developed stress fibers in both FGF and TGFβ1. The Rac inhibitor had no significant impact on growth factor responses in compliant matrices. Within compressed collagen matrices however, the Rac inhibitor induced fibroblastic transformation in serum-free media, PDGF and IGF. Fibroblast and myofibroblast transformation was blocked by Rho kinase inhibition. Overall, keratocyte growth factor responses appear to be regulated by both the interplay between Rho and Rac signaling, and the structural and mechanical properties of the ECM. PMID:25874856

  16. Fibroblastic Transformation of Corneal Keratocytes by Rac Inhibition is Modulated by Extracellular Matrix Structure and Stiffness.

    PubMed

    Petroll, W Matthew; Lakshman, Neema

    2015-04-14

    The goal of this study was to investigate how alterations in extracellular matrix (ECM) biophysical properties modulate corneal keratocyte phenotypes in response to specific wound healing cytokines and Rho GTPases. Rabbit corneal keratocytes were plated within standard collagen matrices (2.5 mg/mL) or compressed collagen matrices (~100 mg/mL) and cultured in serum-free media, PDGF BB, IGF, FGF2 or TGFβ1, with or without the Rac1 inhibitor NSC23766 and/or the Rho kinase inhibitor Y-27632. After 1 to 4 days, cells were labeled for F-actin and imaged using confocal microscopy. Keratocytes within standard collagen matrices (which are highly compliant) maintained a dendritic phenotype following culture in serum-free media, PDGF, IGF and FGF, but developed stress fibers in TGFβ1. Keratocytes within compressed collagen (which has high stiffness and low porosity) maintained a dendritic phenotype following culture in serum-free media, PDGF and IGF, but developed stress fibers in both FGF and TGFβ1. The Rac inhibitor had no significant impact on growth factor responses in compliant matrices. Within compressed collagen matrices however, the Rac inhibitor induced fibroblastic transformation in serum-free media, PDGF and IGF. Fibroblast and myofibroblast transformation was blocked by Rho kinase inhibition. Overall, keratocyte growth factor responses appear to be regulated by both the interplay between Rho and Rac signaling, and the structural and mechanical properties of the ECM.

  17. A FAK-Cas-Rac-lamellipodin signaling module transduces extracellular matrix stiffness into mechanosensitive cell cycling.

    PubMed

    Bae, Yong Ho; Mui, Keeley L; Hsu, Bernadette Y; Liu, Shu-Lin; Cretu, Alexandra; Razinia, Ziba; Xu, Tina; Puré, Ellen; Assoian, Richard K

    2014-06-17

    Tissue and extracellular matrix (ECM) stiffness is transduced into intracellular stiffness, signaling, and changes in cellular behavior. Integrins and several of their associated focal adhesion proteins have been implicated in sensing ECM stiffness. We investigated how an initial sensing event is translated into intracellular stiffness and a biologically interpretable signal. We found that a pathway consisting of focal adhesion kinase (FAK), the adaptor protein p130Cas (Cas), and the guanosine triphosphatase Rac selectively transduced ECM stiffness into stable intracellular stiffness, increased the abundance of the cell cycle protein cyclin D1, and promoted S-phase entry. Rac-dependent intracellular stiffening involved its binding partner lamellipodin, a protein that transmits Rac signals to the cytoskeleton during cell migration. Our findings establish that mechanotransduction by a FAK-Cas-Rac-lamellipodin signaling module converts the external information encoded by ECM stiffness into stable intracellular stiffness and mechanosensitive cell cycling. Thus, lamellipodin is important not only in controlling cellular migration but also for regulating the cell cycle in response to mechanical signals.

  18. Opsonization modulates Rac-1 activation during cell entry by Leishmania amazonensis.

    PubMed

    Morehead, J; Coppens, I; Andrews, N W

    2002-08-01

    Lesions caused by Leishmania amazonensis normally heal, but relapses occur due to parasite persistence in host tissues. It has been proposed that infection of fibroblasts plays an important role in this process by providing the parasites with a safe haven in which to replicate. However, most previous studies have focused on the entry of Leishmania into macrophages, a process mediated by serum opsonins. To gain insight into a possible role of nonopsonic entry in the intracellular persistence of amastigotes, we examined the invasion of Chinese hamster ovary (CHO) cells. Amastigotes entered CHO cells by a cytochalasin D, genistein, wortmannin, and 2,3-butanedione monoxime-sensitive pathway and replicated within phagolysosomes. However, unlike most phagocytic processes described to date, amastigote internalization in CHO cells involved activation of the GTPases Rho and Cdc42 but not Rac-1. When uptake was mediated by fibronectin or when amastigotes were opsonized with immunoglobulin G and internalized by Fc receptor-expressing CHO cells, Rac-1 activation was restored and found to be required for parasite internalization. Given the essential role of Rac in assembly of the respiratory burst oxidase, invasion through this nonopsonic, Rac-1-independent pathway may play a central role in the intracellular survival of Leishmania in immune hosts.

  19. Opsonization Modulates Rac-1 Activation during Cell Entry by Leishmania amazonensis

    PubMed Central

    Morehead, J.; Coppens, I.; Andrews, N. W.

    2002-01-01

    Lesions caused by Leishmania amazonensis normally heal, but relapses occur due to parasite persistence in host tissues. It has been proposed that infection of fibroblasts plays an important role in this process by providing the parasites with a safe haven in which to replicate. However, most previous studies have focused on the entry of Leishmania into macrophages, a process mediated by serum opsonins. To gain insight into a possible role of nonopsonic entry in the intracellular persistence of amastigotes, we examined the invasion of Chinese hamster ovary (CHO) cells. Amastigotes entered CHO cells by a cytochalasin D, genistein, wortmannin, and 2,3-butanedione monoxime-sensitive pathway and replicated within phagolysosomes. However, unlike most phagocytic processes described to date, amastigote internalization in CHO cells involved activation of the GTPases Rho and Cdc42 but not Rac-1. When uptake was mediated by fibronectin or when amastigotes were opsonized with immunoglobulin G and internalized by Fc receptor-expressing CHO cells, Rac-1 activation was restored and found to be required for parasite internalization. Given the essential role of Rac in assembly of the respiratory burst oxidase, invasion through this nonopsonic, Rac-1-independent pathway may play a central role in the intracellular survival of Leishmania in immune hosts. PMID:12117970

  20. Rac GTPase Activating Protein ARHGAP25 Regulates Leukocyte Transendothelial Migration in Mice.

    PubMed

    Csépányi-Kömi, Roland; Wisniewski, Éva; Bartos, Balázs; Lévai, Petra; Németh, Tamás; Balázs, Bernadett; Kurz, Angela R M; Bierschenk, Susanne; Sperandio, Markus; Ligeti, Erzsébet

    2016-10-01

    ARHGAP25 is a Rac-specific GTPase-activating protein that is expressed primarily in hematopoietic cells. The involvement of ARHGAP25 in regulating the recruitment of leukocytes to inflammatory sites was investigated in genetically modified mice. Using intravital microscopy, we show that Arhgap25 deficiency affects all steps of leukocyte recruitment with a predominant enhancement of transendothelial migration of neutrophilic granulocytes. Increased transmigration of Arhgap25-deficient leukocytes is demonstrated in inflamed cremaster muscle venules, in a peritonitis model, and in an in vitro chemotaxis assay. Using bone marrow chimeric mice lacking ARHGAP25 in the hematopoietic compartment, we show that enhanced migration in the absence of ARHGAP25 is due to defective leukocyte function. In search for potential mechanisms of ARHGAP25-regulated migration of neutrophils, we detected an increase in the amount of active, GTP-bound Rac and Rac-dependent cytoskeletal changes in the absence of ARHGAP25, suggesting a critical role of ARHGAP25 in counterbalancing the Rac-activating effect of nucleotide exchange factors. Taken together, using Arhgap25-deficient mice, we identified ARHGAP25 as a relevant negative regulator of leukocyte transendothelial migration. PMID:27566826

  1. 44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS COMMERCIAL NUCLEAR POWER PLANTS: EMERGENCY...) Under 44 CFR part 351, the role of a RAC is to assist State and local government officials to develop.... (b) Prior to a determination under subpart A (44 CFR 352.6(d)) that Federal facilities and...

  2. 75 FR 5563 - Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-03

    ... (RAC) will meet on February 22-23, 2010 in La Grande, Oregon. The purpose of the meeting is to meet as... held in the Blue Mountain Conference Center, 404 12th Street, La Grande, Oregon. FOR FURTHER... Grande Ranger ] District, 3502 Highway 30, La Grande, Oregon 97850; Telephone: (541)...

  3. Plasma Membrane Microdomains Are Essential for Rac1-RbohB/H-Mediated Immunity in Rice.

    PubMed

    Nagano, Minoru; Ishikawa, Toshiki; Fujiwara, Masayuki; Fukao, Yoichiro; Kawano, Yoji; Kawai-Yamada, Maki; Shimamoto, Ko

    2016-08-01

    Numerous plant defense-related proteins are thought to congregate in plasma membrane microdomains, which consist mainly of sphingolipids and sterols. However, the extent to which microdomains contribute to defense responses in plants is unclear. To elucidate the relationship between microdomains and innate immunity in rice (Oryza sativa), we established lines in which the levels of sphingolipids containing 2-hydroxy fatty acids were decreased by knocking down two genes encoding fatty acid 2-hydroxylases (FAH1 and FAH2) and demonstrated that microdomains were less abundant in these lines. By testing these lines in a pathogen infection assay, we revealed that microdomains play an important role in the resistance to rice blast fungus infection. To illuminate the mechanism by which microdomains regulate immunity, we evaluated changes in protein composition, revealing that microdomains are required for the dynamics of the Rac/ROP small GTPase Rac1 and respiratory burst oxidase homologs (Rbohs) in response to chitin elicitor. Furthermore, FAHs are essential for the production of reactive oxygen species (ROS) after chitin treatment. Together with the observation that RbohB, a defense-related NADPH oxidase that interacts with Rac1, is localized in microdomains, our data indicate that microdomains are required for chitin-induced immunity through ROS signaling mediated by the Rac1-RbohB pathway. PMID:27465023

  4. Inhibition of Rac GTPase signaling and downstream prosurvival Bcl-2 proteins as combination targeted therapy in MLL-AF9 leukemia.

    PubMed

    Mizukawa, Benjamin; Wei, Junping; Shrestha, Mahesh; Wunderlich, Mark; Chou, Fu-Sheng; Griesinger, Andrea; Harris, Chad E; Kumar, Ashish R; Zheng, Yi; Williams, David A; Mulloy, James C

    2011-11-10

    The Rac family of small Rho GTPases coordinates diverse cellular functions in hematopoietic cells including adhesion, migration, cytoskeleton rearrangements, gene transcription, proliferation, and survival. The integrity of Rac signaling has also been found to critically regulate cellular functions in the initiation and maintenance of hematopoietic malignancies. Using an in vivo gene targeting approach, we demonstrate that Rac2, but not Rac1, is critical to the initiation of acute myeloid leukemia in a retroviral expression model of MLL-AF9 leukemogenesis. However, loss of either Rac1 or Rac2 is sufficient to impair survival and growth of the transformed MLL-AF9 leukemia. Rac2 is known to positively regulate expression of Bcl-2 family proteins toward a prosurvival balance. We demonstrate that disruption of downstream survival signaling through antiapoptotic Bcl-2 proteins is implicated in mediating the effects of Rac2 deficiency in MLL-AF9 leukemia. Indeed, overexpression of Bcl-xL is able to rescue the effects of Rac2 deficiency and MLL-AF9 cells are exquisitely sensitive to direct inhibition of Bcl-2 family proteins by the BH3-mimetic, ABT-737. Furthermore, concurrent exposure to NSC23766, a small-molecule inhibitor of Rac activation, increases the apoptotic effect of ABT-737, indicating the Rac/Bcl-2 survival pathway may be targeted synergistically.

  5. RAC1 inhibition as a therapeutic target for gefitinib-resistant non-small-cell lung cancer

    PubMed Central

    Kaneto, Naoki; Yokoyama, Satoru; Hayakawa, Yoshihiro; Kato, Shinichiro; Sakurai, Hiroaki; Saiki, Ikuo

    2014-01-01

    Although epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (EGFR-TKI), including gefitinib, provide a significant clinical benefit in non-small-cell lung cancer (NSCLC) patients, the acquisition of drug resistance has been known to limit the efficacy of EGFR-TKI therapy. In this study, we demonstrated the involvement of EGF-EGFR signaling in NSCLC cell migration and the requirement of RAC1 in EGFR-mediated progression of NSCLC. We showed the significant role of RAC1 pathway in the cell migration or lamellipodia formation by using gene silencing of RAC1 or induction of constitutive active RAC1 in EGFR-mutant NSCLC cells. Importantly, the RAC1 inhibition suppressed EGFR-mutant NSCLC cell migration and growth in vitro, and growth in vivo even in the gefitinib-resistant cells. In addition, these suppressions by RAC1 inhibition were mediated through MEK or PI3K independent mechanisms. Collectively, these results open up a new opportunity to control the cancer progression by targeting the RAC1 pathway to overcome the resistance to EGFR-TKI in NSCLC patients. PMID:24750242

  6. The RACs are back: auditors to start performing complex reviews.

    PubMed

    2015-04-01

    The Recovery Auditor program is cranking back up again after almost a year's hiatus, but despite the Centers for Medicare & Medicaid Services' plans to improve the program and issue new contracts, the audits will be conducted by the same auditors under the same rules. Auditors are likely to target short stays and other weak areas the Medicare Administrative Contractors identified during Probe and Educate, according to Elizabeth Lamkin, MHA, chief executive officer and partner in PACE Healthcare Consulting, LLC, based in Beaufort County, SC. CMS has not made any clarifications to the two-midnight rule, and auditors may begin auditing hospitals for compliance beginning April 1. The Outpatient Prospective Payment System (OPPS) final rule clarified the requirement for physician certification, saying that the order to admit must be signed by the treating physician and the justification for the admission, the expected length of stay, the treatment plan, and the discharge plan do not have to be a separate document but can be part of the history and physical. PMID:25842707

  7. Phosphoregulation of MgcRacGAP in mitosis involves Aurora B and Cdk1 protein kinases and the PP2A phosphatase.

    PubMed

    Touré, Aminata; Mzali, Rym; Liot, Caroline; Seguin, Laetitia; Morin, Laurence; Crouin, Catherine; Chen-Yang, Ilin; Tsay, Yeou-Guang; Dorseuil, Olivier; Gacon, Gérard; Bertoglio, Jacques

    2008-04-01

    MgcRacGAP, a Rho GAP essential to cytokinesis, works both as a Rho GTPase regulator and as a scaffolding protein. MgcRacGAP interacts with MKLP1 to form the centralspindlin complex and associates with the RhoGEF Ect2. The GAP activity of MgcRacGAP is regulated by Aurora B phosphorylation. We have isolated B56epsilon, a PP2A regulatory subunit, as a new MgcRacGAP partner. We report here that (i) MgcRacGAP is phosphorylated by Aurora B and Cdk1, (ii) PP2A dephosphorylates Aurora B and Cdk1 phosphorylated sites and (iii) inhibition of PP2A abrogates MgcRacGAP/Ect2 interaction. Therefore, PP2A may regulate cytokinesis by dephosphorylating MgcRacGAP and its interacting partners.

  8. 20 CFR 670.985 - What happens if a center operator, screening and admissions contractor or other service provider...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and admissions contractor or other service provider fails to meet the expected levels of performance... LABOR THE JOB CORPS UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Administrative and Management... provider fails to meet the expected levels of performance? (a) The Secretary takes appropriate action...

  9. Management assessment of tank waste remediation system contractor readiness to proceed with phase 1B privatization

    SciTech Connect

    Honeyman, J.O.

    1998-01-09

    This Management Assessment of Tank Waste Remediation System (TWRS) Contractor Readiness to Proceed With Phase 1B Privatization documents the processes used to determine readiness to proceed with tank waste treatment technologies from private industry, now known as TWRS privatization. An overall systems approach was applied to develop action plans to support the retrieval and disposal mission of the TWRS Project. The systems and infrastructure required to support the mission are known. Required systems are either in place or plans have been developed to ensure they exist when needed. Since October 1996 a robust system engineering approach to establishing integrated Technical Baselines, work breakdown structures, tank farms organizational structure and configurations, work scope, and costs has become part of the culture within the TWRS Project. An analysis of the programmatic, management, and technical activities necessary to declare readiness to proceed with execution of the mission demonstrates that the system, personnel, and hardware will be on-line and ready to support the private contractors. The systems approach included defining the retrieval and disposal mission requirements and evaluating the readiness of the Project Hanford Management Contract (PHMC) team to support initiation of waste processing by the private contractors in June 2002 and to receive immobilized waste shortly thereafter. The Phase 1 feed delivery requirements from the private contractor Requests for Proposal were reviewed. Transfer piping routes were mapped, existing systems were evaluated, and upgrade requirements were defined.

  10. The Rac Inhibitor EHop-016 Inhibits Mammary Tumor Growth and Metastasis in a Nude Mouse Model

    PubMed Central

    Castillo-Pichardo, Linette; Humphries-Bickley, Tessa; De La Parra, Columba; Forestier-Roman, Ingrid; Martinez-Ferrer, Magaly; Hernandez, Eliud; Vlaar, Cornelis; Ferrer-Acosta, Yancy; Washington, Anthony V.; Cubano, Luis A.; Rodriguez-Orengo, Jose; Dharmawardhane, Suranganie

    2014-01-01

    Metastatic disease still lacks effective treatments, and remains the primary cause of cancer mortality. Therefore, there is a critical need to develop better strategies to inhibit metastatic cancer. The Rho family GTPase Rac is an ideal target for anti-metastatic cancer therapy, because Rac is a key molecular switch that is activated by a myriad of cell surface receptors to promote cancer cell migration/invasion and survival. Previously, we reported the design and development of EHop-016, a small molecule compound, which inhibits Rac activity of metastatic cancer cells with an IC50 of 1 μM. EHop-016 also inhibits the activity of the Rac downstream effector p21-activated kinase (PAK), lamellipodia extension, and cell migration in metastatic cancer cells. Herein, we tested the efficacy of EHop-016 in a nude mouse model of experimental metastasis, where EHop-016 administration at 25 mg/kg body weight (BW) significantly reduced mammary fat pad tumor growth, metastasis, and angiogenesis. As quantified by UPLC MS/MS, EHop-016 was detectable in the plasma of nude mice at 17 to 23 ng/ml levels at 12 h following intraperitoneal (i.p.) administration of 10 to 25 mg/kg BW EHop-016. The EHop-016 mediated inhibition of angiogenesis In Vivo was confirmed by immunohistochemistry of excised tumors and by In Vitro tube formation assays of endothelial cells. Moreover, EHop-016 affected cell viability by down-regulating Akt and Jun kinase activities and c-Myc and Cyclin D expression, as well as increasing caspase 3/7 activities in metastatic cancer cells. In conclusion, EHop-016 has potential as an anticancer compound to block cancer progression via multiple Rac-directed mechanisms. PMID:25389450

  11. CDK5 knockdown in astrocytes provide neuroprotection as a trophic source via Rac1.

    PubMed

    Posada-Duque, Rafael Andrés; Palacio-Castañeda, Valentina; Cardona-Gómez, Gloria Patricia

    2015-09-01

    Astrocytes perform metabolic and structural support functions in the brain and contribute to the integrity of the blood-brain barrier. Astrocytes influence neuronal survival and prevent gliotoxicity by capturing glutamate (Glu), reactive oxygen species, and nutrients. During these processes, astrocytic morphological changes are supported by actin cytoskeleton remodeling and require the involvement of Rho GTPases, such as Rac1. The protein cyclin-dependent kinase 5 (CDK5) may have a dual effect on astrocytes because it has been shown to be involved in migration, senescence, and the dysfunction of glutamate recapture; however, its role in astrocytes remains unclear. Treating a possible deregulation of CDK5 with RNAi is a strategy that has been proposed as a therapy for neurodegenerative diseases. Models of glutamate gliotoxicity in the C6 astroglioma cell line, primary cultures of astrocytes, and co-cultures with neurons were used to analyze the effects of CDK5 RNAi in astrocytes and the role of Rac1 in neuronal viability. In C6 cells and primary astrocytes, CDK5 RNAi prevented the cell death generated by glutamate-induced gliotoxicity, and this finding was corroborated by pharmacological inhibition with roscovitine. This effect was associated with the appearance of lamellipodia, protrusions, increased cell area, stellation, Rac1 activation, BDNF release, and astrocytic protection in neurons that were exposed to glutamate excitotoxicity. Interestingly, Rac1 inhibition in astrocytes blocked BDNF upregulation and the astrocyte-mediated neuroprotection. Actin cytoskeleton remodeling and stellation may be a functional phenotype for BDNF release that promotes neuroprotection. In summary, our findings suggest that CDK5- knockdown in astrocytes acts as a trophic source for neuronal protection in a Rac1-dependent manner. PMID:26160434

  12. Role of the guanine nucleotide exchange factor Ost in negative regulation of receptor endocytosis by the small GTPase Rac1.

    PubMed

    Ieguchi, Katsuaki; Ueda, Shuji; Kataoka, Tohru; Satoh, Takaya

    2007-08-10

    The Rho family of GTPases has been implicated in the regulation of intracellular vesicle trafficking. Here, we investigated the mechanism underlying the negative regulation of clathrin-mediated endocytosis of cell surface receptors mediated by the Rho family protein Rac1. Contrary to previous reports, only the activated mutant of Rac1, but not other Rho family members including RhoA and Cdc42, suppressed internalization of the transferrin receptor. On the other hand, down-regulation of Rac1 expression by RNA interference resulted in enhanced receptor internalization, suggesting that endogenous Rac1 in fact functions as a negative regulator. We identified a guanine nucleotide exchange factor splice variant designated Ost-III, which contains a unique C-terminal region including an Src homology 3 domain, as a regulator of Rac1 involved in the inhibition of receptor endocytosis. In contrast, other splice variants Ost-I and Ost-II exerted virtually no effect on receptor endocytosis. We also examined subcellular localization of synaptojanin 2, a putative Rac1 effector implicated in negative regulation of receptor endocytosis. Each Ost splice variant induced distinct subcellular localization of synaptojanin 2, depending on Rac1 activation. Furthermore, we isolated gamma-aminobutyric acid type A receptor-associated protein (GABARAP) as a protein that binds to the C-terminal region of Ost-III. When ectopically expressed, GABARAP was co-localized with Ost-III and potently suppressed the Ost-III-dependent Rac1 activation and the inhibition of receptor endocytosis. Lipid modification of GABARAP was necessary for the suppression of Ost-III. These results are discussed in terms of subcellular region-specific regulation of the Rac1-dependent signaling pathway that negatively regulates clathrin-mediated endocytosis.

  13. R-Ketorolac Targets Cdc42 and Rac1 and Alters Ovarian Cancer Cell Behaviors Critical for Invasion and Metastasis.

    PubMed

    Guo, Yuna; Kenney, S Ray; Muller, Carolyn Y; Adams, Sarah; Rutledge, Teresa; Romero, Elsa; Murray-Krezan, Cristina; Prekeris, Rytis; Sklar, Larry A; Hudson, Laurie G; Wandinger-Ness, Angela

    2015-10-01

    Cdc42 (cell division control protein 42) and Rac1 (Ras-related C3 botulinum toxin substrate 1) are attractive therapeutic targets in ovarian cancer based on established importance in tumor cell migration, adhesion, and invasion. Despite a predicted benefit, targeting GTPases has not yet been translated to clinical practice. We previously established that Cdc42 and constitutively active Rac1b are overexpressed in primary ovarian tumor tissues. Through high-throughput screening and computational shape homology approaches, we identified R-ketorolac as a Cdc42 and Rac1 inhibitor, distinct from the anti-inflammatory, cyclooxygenase inhibitory activity of S-ketorolac. In the present study, we establish R-ketorolac as an allosteric inhibitor of Cdc42 and Rac1. Cell-based assays validate R-ketorolac activity against Cdc42 and Rac1. Studies on immortalized human ovarian adenocarcinoma cells (SKOV3ip) and primary patient-derived ovarian cancer cells show that R-ketorolac is a robust inhibitor of growth factor or serum-dependent Cdc42 and Rac1 activation with a potency and cellular efficacy similar to small-molecule inhibitors of Cdc42 (CID2950007/ML141) and Rac1 (NSC23766). Furthermore, GTPase inhibition by R-ketorolac reduces downstream p21-activated kinases (PAK1/PAK2) effector activation by >80%. Multiple assays of cell behavior using SKOV3ip and primary patient-derived ovarian cancer cells show that R-ketorolac significantly inhibits cell adhesion, migration, and invasion. In summary, we provide evidence for R-ketorolac as a direct inhibitor of Cdc42 and Rac1 that is capable of modulating downstream GTPase-dependent, physiologic responses, which are critical to tumor metastasis. Our findings demonstrate the selective inhibition of Cdc42 and Rac1 GTPases by an FDA-approved drug, racemic ketorolac, that can be used in humans.

  14. The role of Rac1 in the regulation of NF-kB activity, cell proliferation, and cell migration in non-small cell lung carcinoma

    PubMed Central

    Gastonguay, Adam; Berg, Tracy; Hauser, Andrew D.; Schuld, Nathan; Lorimer, Ellen; Williams, Carol L.

    2012-01-01

    The small GTPase Rac1 regulates many cellular processes, including cytoskeletal reorganization, cell migration, proliferation, and survival. Additionally, Rac1 plays a major role in activating NF-κB-mediated transcription. Both Rac1 and NF-κB regulate many properties of the malignant phenotype, including anchorage-independent proliferation and survival, metastasis, and angiogenesis. Despite these findings, the roles of Rac1and NF-κB in non-small cell lung carcinoma, a leading cause of cancer deaths, have not been thoroughly investigated. Here, we compared the effects of Rac1 siRNA to that of the Rac1 inhibitor NSC23766 on multiple features of the NSCLC malignant phenotype, including NF-κB activity. We show that the siRNA-mediated silencing of Rac1 in lung cancer cells results in decreased cell proliferation and migration. The decrease in proliferation was observed in both anchorage-dependent and anchorage-independent assays. Furthermore, cells with decreased Rac1 expression have a slowed progression through the G1 phase of the cell cycle. These effects induced by Rac1 siRNA correlated with a decrease in NF-κB transcriptional activity. Additionally, inhibition of NF-κB signaling with BAY 11–7082 inhibited proliferation; indicating that the loss of cell proliferation and migration induced by the silencing of Rac1 expression may be attributed in part to loss of NF-κB activity. Interestingly, treatment with the Rac1 inhibitor NSC23766 strongly inhibits cell proliferation, cell cycle progression, and NF-κB activity in lung cancer cells, to an even greater extent than the inhibition induced by Rac1 siRNA. These findings indicate that Rac1 plays an important role in lung cancer cell proliferation and migration, most likely through its ability to promote NF-κB activity, and highlight Rac1 pathways as therapeutic targets for the treatment of lung cancer. PMID:22549160

  15. The role of Rac1 in the regulation of NF-κB activity, cell proliferation, and cell migration in non-small cell lung carcinoma.

    PubMed

    Gastonguay, Adam; Berg, Tracy; Hauser, Andrew D; Schuld, Nathan; Lorimer, Ellen; Williams, Carol L

    2012-06-01

    The small GTPase Rac1 regulates many cellular processes, including cytoskeletal reorganization, cell migration, proliferation, and survival. Additionally, Rac1 plays a major role in activating NF-κB-mediated transcription. Both Rac1 and NF-κB regulate many properties of the malignant phenotype, including anchorage-independent proliferation and survival, metastasis, and angiogenesis. Despite these findings, the roles of Rac1and NF-κB in non-small cell lung carcinoma, a leading cause of cancer deaths, have not been thoroughly investigated. Here, we compared the effects of Rac1 siRNA to that of the Rac1 inhibitor NSC23766 on multiple features of the NSCLC malignant phenotype, including NF-κB activity. We show that the siRNA-mediated silencing of Rac1 in lung cancer cells results in decreased cell proliferation and migration. The decrease in proliferation was observed in both anchorage-dependent and anchorage-independent assays. Furthermore, cells with decreased Rac1 expression have a slowed progression through the G 1 phase of the cell cycle. These effects induced by Rac1 siRNA correlated with a decrease in NF-κB transcriptional activity. Additionally, inhibition of NF-κB signaling with BAY 11-7082 inhibited proliferation; indicating that the loss of cell proliferation and migration induced by the silencing of Rac1 expression may be attributed in part to loss of NF-κB activity. Interestingly, treatment with the Rac1 inhibitor NSC23766 strongly inhibits cell proliferation, cell cycle progression, and NF-κB activity in lung cancer cells, to an even greater extent than the inhibition induced by Rac1 siRNA. These findings indicate that Rac1 plays an important role in lung cancer cell proliferation and migration, most likely through its ability to promote NF-κB activity, and highlight Rac1 pathways as therapeutic targets for the treatment of lung cancer.

  16. National Radon Contractor Proficiency (RCP) Program. Proficiency report, June 1991

    SciTech Connect

    Not Available

    1991-06-01

    The primary objective of the U.S. Environmental Protection Agency's (EPA) efforts to address the indoor radon problem is to reduce radon levels in buildings throughout the country. Achieving the objective requires a nationwide supply of capable radon mitigation contractors. In the Indoor Radon Abatement Act of 1988, Congress authorized EPA to establish a program to evaluate radon mitigation contractors and to provide the information to the public in cooperation with the States. The Radon Contractor Proficiency (RCP) Program was developed to assist States, EPA Regions, local government officials, and the public in selecting contractors who have demonstrated their proficiency in reducing indoor radon levels. The program is managed by the EPA Office of Radiation Programs' Radon Division. Under the voluntary program, radon contractors demonstrate their proficiency by meeting specific Program requirements. Individual contractors who meet these requirements are then listed in periodic RCP Proficiency Reports.

  17. National radon contractor proficiency (RCP) program. Proficiency report, January 1993

    SciTech Connect

    Not Available

    1993-01-01

    The primary objective of the U.S. Environmental Protection Agency's (EPA) efforts to address the indoor radon problem is to reduce radon levels in buildings throughout the country. Achieving the objective requires a nationwide supply of capable radon mitigation contractors. In the Indoor Radon Abatement Act of 1988, Congress authorized EPA to establish a program to evaluate radon mitigation contractors and to provide the information to the public in cooperation with the States. The Radon Contractor Proficiency (RCP) Program was developed to assist States, EPA Regions, local government officials, and the public in selecting contractors who have demonstrated their proficiency in reducing indoor radon levels. The program is managed by the EPA Office of Radiation Programs' Radon Division. Under the voluntary program, radon contractors demonstrate their proficiency by meeting specific Program requirements. Individual contractors who meet these requirements are then listed in the Report.

  18. National Radon Contractor Proficiency (RCP) program. Proficiency report, September 1991

    SciTech Connect

    Not Available

    1991-09-01

    The primary objective of the U.S. Environmental Protection Agency's (EPA) efforts to address the indoor radon problem is to reduce radon levels in buildings throughout the country. Achieving this objective requires a nationwide supply of capable radon mitigation contractors. In the Indoor Radon Abatement Act of 1988, Congress authorized EPA to establish a program to evaluate radon mitigation contractors and to provide this information to the public in cooperation with the States. The Radon Contractor Proficiency (RCP) Program was developed to assist States, EPA Regions, local government officials, and the public in selecting contractors who have demonstrated their proficiency in reducing indoor radon levels. The program is managed by the EPA Office of Radiation Programs' Radon Division. Under this voluntary program, radon contractors demonstrate their proficiency by meeting specific Program requirements. Individual contractors who meet these requirements are then listed in the Report.

  19. National Radon Contractor Proficiency (RCP) program. Proficiency report, July 1992

    SciTech Connect

    Not Available

    1992-07-01

    The primary objective of the U.S. Environmental Protection Agency's (EPA) efforts to address the indoor radon problem is to reduce radon levels in buildings throughout the country. Achieving this objective requires a nationwide supply of capable radon mitigation contractors. In the Indoor Radon Abatement Act of 1988, Congress authorized EPA to establish a program to evaluate radon mitigation contractors and to provide this information to the public in cooperation with the States. The Radon Contractor Proficiency (RCP) Program was developed to assist States, EPA Regions, local government officials, and the public in selecting contractors who have demonstrated their proficiency in reducing indoor radon levels. This program is managed by the EPA Office of Radiation Programs' Radon Division. Under this voluntary program, radon contractors demonstrate their proficiency by meeting specific Program requirements. Individual contractors who meet these requirements are then listed in the Report.

  20. National Radon Contractor Proficiency (RCP) Program. Proficiency report, January 1992

    SciTech Connect

    Not Available

    1992-01-01

    The primary objective of the U.S. Environmental Protection Agency's (EPA) efforts to address the indoor radon problem is to reduce radon levels in buildings throughout the country. Achieving the objective requires a nationwide supply of capable radon mitigation contractors. In the Indoor Radon Abatement Act of 1988, Congress authorized EPA to establish a program to evaluate radon mitigation contractors and to provide the information to the public in cooperation with the States. The Radon Contractor Proficiency (RCP) Program was developed to assist States, EPA Regions, local government officials, and the public in selecting contractors who have demonstrated their proficiency in reducing indoor radon levels. The program is managed by the EPA Office of Radiation Programs' Radon Division. Under the voluntary program, radon contractors demonstrate their proficiency by meeting specific Program requirements. Individual contractors who meet these requirements are then listed in the Report.

  1. The contractor`s role in low-level waste disposal facility application review and licensing

    SciTech Connect

    Serie, P.J.; Dressen, A.L.

    1991-12-31

    The California Department of Health Services will soon reach a licensing decision on the proposed Ward Valley low-level radioactive waste disposal facility. As the first regulatory agency in the country to address the 10 CFR Part 61 requirements for a new disposal facility, California`s program has broken new ground in its approach. Throughout the review process, the Department has relied on contractor support to augment its technical and administrative staff. A team consisting of Roy F. Weston, Inc., supported by ERM-Program Management Corp., Environmental Issues Management, Inc., and Rogers and Associates Engineering Corporation, has worked closely with the Department in a staff extension role. The authors have been involved with the project in contractor project management roles since 1987, and continue to support the Department`s program as it proceeds to finalize its licensing process. This paper describes the selection process used to identify a contractor team with the needed skills and experience, and the makeup of team capabilities. It outlines the management, communication, and technical approaches used to assure a smooth agency-contractor function and relationship. It describes the techniques used to ensure that decisions and documents represented the Department credibly in its role as the regulatory and licensing agency under the Nuclear Regulatory Commission (NRC) Agreement State program. The paper outlines the license application review process and activities, through preparation of licensing documentation and responses to public comments. Lessons learned in coordination of an agency-contractor team effort to review and license a low-level waste disposal facility are reviewed and suggestions made for approaching a similar license application review and licensing situation.

  2. 75 FR 69687 - Office of Biotechnology Activities Recombinant DNA Research: Proposed Actions Under the NIH...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... HUMAN SERVICES National Institutes of Health Office of Biotechnology Activities Recombinant DNA Research: Proposed Actions Under the NIH Guidelines for Research Involving Recombinant DNA Molecules (NIH Guidelines... the NIH Recombinant DNA Advisory Committee (RAC) and specifically approved by the NIH Director as...

  3. 48 CFR 923.102 - Applicability to contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PROGRAMS ENVIRONMENT, CONSERVATION, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Sustainable Acquisition... sustainable products and services by its facility support contractors. The DOE Sustainable Acquisition...

  4. 10 CFR 824.16 - Direction to NNSA contractors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... INFORMATION SECURITY VIOLATIONS § 824.16 Direction to NNSA contractors. (a) Notwithstanding any other... compel attendance; (3) Disclosures of information or documents obtained during an investigation...

  5. 48 CFR 970.0309 - Whistleblower Protection of Contractor Employees.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OF ENERGY AGENCY SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Improper Business Practices and Personal Conflicts of Interest 970.0309 Whistleblower Protection of Contractor Employees....

  6. Maintenance and operations contractor plan for transition to the project Hanford management contract (PHMC)

    SciTech Connect

    Waite, J.L.

    1996-04-12

    This plan has been developed by Westinghouse Hanford Company (WHC), and its subcontractors ICF Kaiser Hanford (ICF KH) and BCS Richland, Inc. (BCSR), at the direction of the US Department of Energy (DOE), Richland Operations Office (RL). WHC and its subcontractors are hereafter referred to as the Maintenance and Operations (M and O) Contractor. The plan identifies actions involving the M and O Contractor that are critical to (1) prepare for a smooth transition to the Project Hanford Management Contractor (PHMC), and (2) support and assist the PHMC and RL in achieving transition as planned, with no or minimal impact to ongoing baseline activities. The plan is structured around two primary phases. The first is the pre-award phase, which started in mid-February 1996 and is currently scheduled to be completed on June 1, 1996, at which time the contract is currently planned to be awarded. The second is the follow-on four-month post-award phase from June 1, 1996, until October 1, 1996. Considering the magnitude and complexity of the scope of work being transitioned, completion in four months will require significant effort by all parties. To better ensure success, the M and O Contractor has developed a pre-award phase that is intended to maximize readiness for transition. Priority is given to preparation for facility assessments and processing of personnel, as these areas are determined to be on the critical path for transition. In addition, the M and O Contractor will put emphasis during the pre-award phase to close out open items prior to contract award, to include grievances, employee concerns, audit findings, compliance issues, etc.

  7. Modulation of host signaling by a bacterial mimic: structure of the Salmonella effector SptP bound to Rac1.

    PubMed

    Stebbins, C E; Galán, J E

    2000-12-01

    Salmonella spp. utilize a specialized protein secretion system to deliver a battery of effector proteins into host cells. Several of these effectors stimulate Cdc42- and Rac1-dependent cytoskeletal changes that promote bacterial internalization. These potentially cytotoxic alterations are rapidly reversed by the effector SptP, a tyrosine phosphatase and GTPase activating protein (GAP) that targets Cdc42 and Rac1. The 2.3 A resolution crystal structure of an SptP-Rac1 transition state complex reveals an unusual GAP architecture that mimics host functional homologs. The phosphatase domain possesses a conserved active site but distinct surface properties. Binding to Rac1 induces a dramatic stabilization in SptP of a four-helix bundle that makes extensive contacts with the Switch I and Switch II regions of the GTPase.

  8. The Rac1 inhibitor NSC23766 exerts anti-influenza virus properties by affecting the viral polymerase complex activity.

    PubMed

    Dierkes, Rüdiger; Warnking, Kathrin; Liedmann, Swantje; Seyer, Roman; Ludwig, Stephan; Ehrhardt, Christina

    2014-01-01

    The frequent emergence of new influenza viruses in the human population underlines the urgent need for antiviral therapeutics in addition to the preventative vaccination against the seasonal flu. To circumvent the development of resistance, recent antiviral approaches target cellular proteins needed by the virus for efficient replication. We investigated the contribution of the small GTPase Rac1 to the replication of influenza viruses. Inhibition of Rac1 by NSC23766 resulted in impaired replication of a wide variety of influenza viruses, including a human virus strain of the pandemic from 2009 as well as highly pathogenic avian virus strains. Furthermore, we identified a crucial role of Rac1 for the activity of the viral polymerase complex. The antiviral potential of NSC23766 was confirmed in mouse experiments, identifying Rac1 as a new cellular target for therapeutic treatment of influenza virus infections.

  9. A central role for the small GTPase Rac1 in hippocampal plasticity and spatial learning and memory

    PubMed Central

    Haditsch, Ursula; Leone, Dino P.; Farinelli, Mélissa; Chrostek-Grashoff, Anna; Brakebusch, Cord; Mansuy, Isabelle M.; McConnell, Susan K.; Palmer, Theo D.

    2009-01-01

    Rac1 is a member of the Rho family of small GTPases that are important for structural aspects of the mature neuronal synapse including basal spine density and shape, activity-dependent spine enlargement, and AMPA receptor clustering in vitro. Here we demonstrate that selective elimination of Rac1 in excitatory neurons in the forebrain in vivo not only affects spine structure, but also impairs synaptic plasticity in the hippocampus with consequent defects in hippocampus-dependent spatial learning. Furthermore, Rac1 mutants display deficits in working/episodic-like memory in the delayed matching-to-place (DMP) task suggesting that Rac1 is a central regulator of rapid encoding of novel spatial information in vivo. PMID:19394428

  10. Rac1 augments Wnt signaling by stimulating β-catenin–lymphoid enhancer factor-1 complex assembly independent of β-catenin nuclear import

    PubMed Central

    Jamieson, Cara; Lui, Christina; Brocardo, Mariana G.; Martino-Echarri, Estefania; Henderson, Beric R.

    2015-01-01

    ABSTRACT β-Catenin transduces the Wnt signaling pathway and its nuclear accumulation leads to gene transactivation and cancer. Rac1 GTPase is known to stimulate β-catenin-dependent transcription of Wnt target genes and we confirmed this activity. Here we tested the recent hypothesis that Rac1 augments Wnt signaling by enhancing β-catenin nuclear import; however, we found that silencing/inhibition or up-regulation of Rac1 had no influence on nuclear accumulation of β-catenin. To better define the role of Rac1, we employed proximity ligation assays (PLA) and discovered that a significant pool of Rac1–β-catenin protein complexes redistribute from the plasma membrane to the nucleus upon Wnt or Rac1 activation. More importantly, active Rac1 was shown to stimulate the formation of nuclear β-catenin–lymphoid enhancer factor 1 (LEF-1) complexes. This regulation required Rac1-dependent phosphorylation of β-catenin at specific serines, which when mutated (S191A and S605A) reduced β-catenin binding to LEF-1 by up to 50%, as revealed by PLA and immunoprecipitation experiments. We propose that Rac1-mediated phosphorylation of β-catenin stimulates Wnt-dependent gene transactivation by enhancing β-catenin–LEF-1 complex assembly, providing new insight into the mechanism of cross-talk between Rac1 and canonical Wnt/β-catenin signaling. PMID:26403202

  11. Remedial Action Contacts Directory - 1997

    SciTech Connect

    1997-05-01

    This document, which was prepared for the US Department of Energy (DOE) Office of Environmental Restoration (ER), is a directory of 2628 individuals interested or involved in environmental restoration and/or remedial actions at radioactively contaminated sites. This directory contains a list of mailing addresses and phone numbers of DOE operations, area, site, project, and contractor offices; an index of DOE operations, area, site, project, and contractor office sorted by state; a list of individuals, presented by last name, facsimile number, and e-mail address; an index of affiliations presented alphabetically, with individual contacts appearing below each affiliation name; and an index of foreign contacta sorted by country and affiliation. This document was generated from the Remedial Action Contacts Database, which is maintained by the Remedial Action Program Information Center (RAPIC).

  12. Legal issues in environmental contractor liability

    SciTech Connect

    Slap, A.J.

    1994-12-31

    Business is booming for environmental professionals. Increasingly, environmental consultants and engineers are called upon by property owners and government agencies to clean up contaminated sites, assess environmental risk for potential purchasers and lenders, and investigate the extent of contamination prior to a real estate purchase. But these activities are not risk-free for the environmental professional. To the contrary, there are many ways for a remediation or site assessment to go awry. Risks that the remediation contractor face include the possibility that activities on the site may actually cause or contribute to further releases of the hazardous substances sought to be remediated. Because environmental professionals many times face substantial risk in performing their jobs, it is necessary that they understand and appreciate the potential liabilities when something does go wrong, and how to best protect themselves. This article describes the types of legal theories that could be brought against environmental professionals and how to best protect yourself from such liability.

  13. Contractor and Government: Teamwork and Commitment

    NASA Technical Reports Server (NTRS)

    Griffin, Gerald D.

    1984-01-01

    The assigned topic, "Contractor and Government: Teamwork and Commitment," is a subject about vitally interested. The successes of the U.S. space program were built on such teamwork and commitment. It seems only a short time ago that man's role in space was an unknown quantity. In rapid succession, however, the flights of Shepard, Glenn, and Armstrong demonstrated man's capability to live and travel in space. Consequently, we no longer live with the same awe of space. The success of these joint industry-NASA efforts in achieving our Nation's space goals testifies to the validity of our team's past commitment, management expertise, communications techniques, and teamwork over a period of 25 years. Today, however, We are at the beginning of a new era in space.

  14. RhoA and Rac1 GTPases Differentially Regulate Agonist-Receptor Mediated Reactive Oxygen Species Generation in Platelets

    PubMed Central

    Akbar, Huzoor; Duan, Xin; Saleem, Saima; Davis, Ashley K.; Zheng, Yi

    2016-01-01

    Agonist induced generation of reactive oxygen species (ROS) by NADPH oxidases (NOX) enhances platelet aggregation and hence the risk of thrombosis. RhoA and Rac1 GTPases are involved in ROS generation by NOX in a variety of cells, but their roles in platelet ROS production remain unclear. In this study we used platelets from RhoA and Rac1 conditional knockout mice as well as human platelets treated with Rhosin and NSC23767, rationally designed small molecule inhibitors of RhoA and Rac GTPases, respectively, to better define the contributions of RhoA and Rac1 signaling to ROS generation and platelet activation. Treatment of platelets with Rhosin inhibited: (a) U46619 induced activation of RhoA; (b) phosphorylation of p47phox, a critical component of NOX; (c) U46619 or thrombin induced ROS generation; (d) phosphorylation of myosin light chain (MLC); (e) platelet shape change; (f) platelet spreading on immobilized fibrinogen; and (g) release of P-selectin, secretion of ATP and aggregation. Conditional deletion of RhoA or Rac1 gene inhibited thrombin induced ROS generation in platelets. Addition of Y27632, a RhoA inhibitor, NSC23766 or Phox-I, an inhibitor of Rac1-p67phox interaction, to human platelets blocked thrombin induced ROS generation. These data suggest that: (a) RhoA/ROCK/p47phox signaling axis promotes ROS production that, at least in part, contributes to platelet activation in conjunction with or independent of the RhoA/ROCK mediated phosphorylation of MLC; and (b) RhoA and Rac1 differentially regulate ROS generation by inhibiting phosphorylation of p47phox and Rac1-p67phox interaction, respectively. PMID:27681226

  15. Agonist Activation of F-Actin-Mediated Eosinophil Shape Change and Mediator Release Is Dependent on Rac2

    PubMed Central

    Lacy, Paige; Willetts, Lian; Kim, John D.; Lo, Andrea N.; Lam, Bon; MacLean, Emily I.; Moqbel, Redwan; Rothenberg, Marc E.; Zimmermann, Nives

    2011-01-01

    Background Tissue recruitment and activation of eosinophils contribute to allergic symptoms by causing airway hyperresponsiveness and inflammation. Shape changes and mediator release in eosinophils may be regulated by mammalian Rho-related guanosine triphosphatases. Of these, Rac2 is essential for F-actin formation as a central process underlying cell motility, exocytosis, and respiratory burst in neutrophils, while the role of Rac2 in eosinophils is unknown. We set out to determine the role of Rac2 in eosinophil mediator release and F-actin-dependent shape change in response to chemotactic stimuli. Methods Rac2-deficient eosinophils from CD2-IL-5 transgenic mice crossed with rac2 gene knockout animals were examined for their ability to release superoxide through respiratory burst or eosinophil peroxidase by degranulation. Eosinophil shape change and actin polymerization were also assessed by flow cytometry and confocal microscopy following stimulation with eotaxin-2 or platelet-activating factor. Results Eosinophils from wild-type mice displayed inducible superoxide release, but at a small fraction (4–5%) of human eosinophils. Rac2-deficient eosinophils showed significantly less superoxide release (p < 0.05, 26% less than wild type). Eosinophils lacking Rac2 had diminished degranulation (p < 0.05, 62% less eosinophil peroxidase) and shape changes in response to eotaxin-2 or platelet-activating factor (with 68 and 49% less F-actin formation, respectively; p < 0.02) compared with wild-type cells. Conclusion These results demonstrate that Rac2 is an important regulator of eosinophil function by contributing to superoxide production, granule protein release, and eosinophil shape change. Our findings suggest that Rho guanosine triphosphatases are key regulators of cellular inflammation in allergy and asthma. PMID:21576984

  16. Role of Rac 1 and cAMP in endothelial barrier stabilization and thrombin-induced barrier breakdown.

    PubMed

    Baumer, Y; Spindler, V; Werthmann, R C; Bünemann, M; Waschke, J

    2009-09-01

    Barrier stabilizing effects of cAMP as well as of the small GTPase Rac 1 are well established. Moreover, it is generally believed that permeability-increasing mediators such as thrombin disrupt endothelial barrier functions primarily via activation of Rho A. In this study, we provide evidence that decrease of both cAMP levels and of Rac 1 activity contribute to thrombin-mediated barrier breakdown. Treatment of human dermal microvascular endothelial cells (HDMEC) with Rac 1-inhibitor NSC-23766 decreased transendothelial electrical resistance (TER) and caused intercellular gap formation. These effects were reversed by addition of forskolin/rolipram (F/R) to increase intracellular cAMP but not by the cAMP analogue 8-pCPT-2'-O-Methyl-cAMP (O-Me-cAMP) which primarily stimulates protein kinase A (PKA)-independent signaling via Epac/Rap 1. However, both F/R and O-Me-cAMP did not increase TER above control levels in the presence of NSC-23766 in contrast to experiments without Rac 1 inhibition. Because Rac 1 was required for maintenance of barrier functions as well as for cAMP-mediated barrier stabilization, we tested the role of Rac 1 and cAMP in thrombin-induced barrier breakdown. Thrombin-induced drop of TER and intercellular gap formation were paralleled by a rapid decrease of cAMP as revealed by fluorescence resonance energy transfer (FRET). The efficacy of F/R or O-Me-cAMP to block barrier-destabilizing effects of thrombin was comparable to Y27632-induced inhibition of Rho kinase but was blunted when Rac 1 was inactivated by NSC-23766. Taken together, these data indicate that decrease of cAMP and Rac 1 activity may be an important step in inflammatory barrier disruption.

  17. Rab5 is required in metastatic cancer cells for Caveolin-1-enhanced Rac1 activation, migration and invasion.

    PubMed

    Díaz, Jorge; Mendoza, Pablo; Ortiz, Rina; Díaz, Natalia; Leyton, Lisette; Stupack, Dwayne; Quest, Andrew F G; Torres, Vicente A

    2014-06-01

    Rab5 is a small GTPase that regulates early endosome trafficking and other cellular processes, including cell adhesion and migration. Specifically, Rab5 promotes Rac1 activation and cancer cell migration, but little is known about the upstream regulators of Rab5. We have previously shown that the scaffolding protein Caveolin-1 (CAV1) promotes Rac1 activation and migration of cancer cells. Here, we hypothesized that CAV1 stimulates Rab5 activation, leading to increased Rac1 activity and cell migration. Expression of CAV1 in B16-F10 mouse melanoma and HT-29(US) human colon adenocarcinoma cells increased the GTP loading of Rab5, whereas shRNA-mediated targeting of endogenous CAV1 in MDA-MB-231 breast cancer cells decreased Rab5-GTP levels. Accordingly, shRNA-mediated downregulation of Rab5 decreased CAV1-mediated Rac1 activation, cell migration and invasion in B16-F10 and HT-29(US) cells. Expression of CAV1 was accompanied by increased recruitment of Tiam1, a Rac1 guanine nucleotide exchange factor (GEF), to Rab5-positive early endosomes. Using the inhibitor NSC23766, Tiam1 was shown to be required for Rac1 activation and cell migration induced by CAV1 and Rab5. Mechanistically, we provide evidence implicating p85α (also known as PIK3R1), a Rab5 GTPase-activating protein (GAP), in CAV1-dependent effects, by showing that CAV1 recruits p85α, precluding p85α-mediated Rab5 inactivation and increasing cell migration. In summary, these studies identify a novel CAV1-Rab5-Rac1 signaling axis, whereby CAV1 prevents Rab5 inactivation, leading to increased Rac1 activity and enhanced tumor cell migration and invasion.

  18. Phosphorylation of SRSF1 by SRPK1 regulates alternative splicing of tumor-related Rac1b in colorectal cells.

    PubMed

    Gonçalves, Vânia; Henriques, Andreia F A; Henriques, Andreia; Pereira, Joana F S; Pereira, Joana; Neves Costa, Ana; Moyer, Mary Pat; Moita, Luís Ferreira; Gama-Carvalho, Margarida; Matos, Paulo; Jordan, Peter

    2014-04-01

    The premessenger RNA of the majority of human genes can generate various transcripts through alternative splicing, and different tissues or disease states show specific patterns of splicing variants. These patterns depend on the relative concentrations of the splicing factors present in the cell nucleus, either as a consequence of their expression levels or of post-translational modifications, such as protein phosphorylation, which are determined by signal transduction pathways. Here, we analyzed the contribution of protein kinases to the regulation of alternative splicing variant Rac1b that is overexpressed in certain tumor types. In colorectal cells, we found that depletion of AKT2, AKT3, GSK3β, and SRPK1 significantly decreased endogenous Rac1b levels. Although knockdown of AKT2 and AKT3 affected only Rac1b protein levels suggesting a post-splicing effect, the depletion of GSK3β or SRPK1 decreased Rac1b alternative splicing, an effect mediated through changes in splicing factor SRSF1. In particular, the knockdown of SRPK1 or inhibition of its catalytic activity reduced phosphorylation and subsequent translocation of SRSF1 to the nucleus, limiting its availability to promote the inclusion of alternative exon 3b into the Rac1 pre-mRNA. Altogether, the data identify SRSF1 as a prime regulator of Rac1b expression in colorectal cells and provide further mechanistic insight into how the regulation of alternative splicing events by protein kinases can contribute to sustain tumor cell survival.

  19. Caveolin-1 Regulates Rac1 Activation and Rat Pulmonary Microvascular Endothelial Hyperpermeability Induced by TNF-α

    PubMed Central

    Sun, Geng-Yun; You, Qing-Hai; Wang, Nan; Zhang, Dan

    2013-01-01

    A multiplicity of vital cellular and tissue level functions are controlled by caveolin-1 and it is considered to be an important candidate for targeted therapeutics. Rac1-cortactin signaling plays an important role in maintaining the functions of the endothelial barrier in microvascular endothelial cells. The activity of Rac1 has been shown to be regulated by caveolin-1. Therefore, the present study investigated the consequences of down-regulating caveolin-1 and the subsequent changes in activity of Rac1 and the endothelial barrier functions in primary rat pulmonary microvascular endothelial cells (RPMVECs). RPMVECs were transfected with a small hairpin RNA duplex to down-regulate caveolin-1 expression. This procedure significantly increased the activity of Rac1. Moreover, down-regulation of caveolin-1 attenuated TNF-α-induced decrease in TER, increase in the flux of FITC-BSA and the disappearance of cortactin from the cell periphery in RPMVEC. Rac1 inhibitors significantly abolished this barrier-protective effect induced by down-regulation of caveolin-1 in response to TNF-α in RPMVECs. In conclusion, our data suggest a mechanism for the regulation of Rac1 activity by caveolin-1, with consequences for activation of endothelial cells in response to TNF-α. PMID:23383114

  20. Rac-mediated Stimulation of Phospholipase Cγ2 Amplifies B Cell Receptor-induced Calcium Signaling*♦

    PubMed Central

    Walliser, Claudia; Tron, Kyrylo; Clauss, Karen; Gutman, Orit; Kobitski, Andrei Yu.; Retlich, Michael; Schade, Anja; Röcker, Carlheinz; Henis, Yoav I.; Nienhaus, G. Ulrich; Gierschik, Peter

    2015-01-01

    The Rho GTPase Rac is crucially involved in controlling multiple B cell functions, including those regulated by the B cell receptor (BCR) through increased cytosolic Ca2+. The underlying molecular mechanisms and their relevance to the functions of intact B cells have thus far remained unknown. We have previously shown that the activity of phospholipase Cγ2 (PLCγ2), a key constituent of the BCR signalosome, is stimulated by activated Rac through direct protein-protein interaction. Here, we use a Rac-resistant mutant of PLCγ2 to functionally reconstitute cultured PLCγ2-deficient DT40 B cells and to examine the effects of the Rac-PLCγ2 interaction on BCR-mediated changes of intracellular Ca2+ and regulation of Ca2+-regulated and nuclear-factor-of-activated-T-cell-regulated gene transcription at the level of single, intact B cells. The results show that the functional Rac-PLCγ2 interaction causes marked increases in the following: (i) sensitivity of B cells to BCR ligation; (ii) BCR-mediated Ca2+ release from intracellular stores; (iii) Ca2+ entry from the extracellular compartment; and (iv) nuclear translocation of the Ca2+-regulated nuclear factor of activated T cells. Hence, Rac-mediated stimulation of PLCγ2 activity serves to amplify B cell receptor-induced Ca2+ signaling. PMID:25903139

  1. The small Rho GTPase Rac1 controls normal human dermal fibroblasts proliferation with phosphorylation of the oncoprotein c-myc

    SciTech Connect

    Nikolova, Ekaterina; Mitev, Vanio; Zhelev, Nikolai; Deroanne, Christophe F. . E-mail: yves.poumay@fundp.ac.be

    2007-08-03

    Proliferation of dermal fibroblasts is crucial for the maintenance of skin. The small Rho GTPase, Rac1, has been identified as a key transducer of proliferative signals in various cell types, but in normal human dermal fibroblasts its significance to cell growth control has not been studied. In this study, we applied the method of RNA interference to suppress endogenous Rac1 expression and examined the consequences on human skin fibroblasts. Rac1 knock-down resulted in inhibition of DNA synthesis. This effect was not mediated by inhibition of the central transducer of proliferative stimuli, ERK1/2 or by activation of the pro-apoptotic p38. Rather, as a consequence of the suppressed Rac1 expression we observed a significant decrease in phosphorylation of c-myc, revealing for the first time that in human fibroblasts Rac1 exerts control on proliferation through c-myc phosphorylation. Thus Rac1 activates proliferation of normal fibroblasts through stimulation of c-myc phosphorylation without affecting ERK1/2 activity.

  2. The Rac-GAP Bcr is a novel regulator of the Par complex that controls cell polarity

    PubMed Central

    Narayanan, Anjana S.; Reyes, Steve B.; Um, Kyongmi; McCarty, Joseph H.; Tolias, Kimberley F.

    2013-01-01

    Cell polarization is essential for many biological processes, including directed cell migration, and loss of polarity contributes to pathological conditions such as cancer. The Par complex (Par3, Par6, and PKCζ) controls cell polarity in part by recruiting the Rac-specific guanine nucleotide exchange factor T-lymphoma invasion and metastasis 1 (Tiam1) to specialized cellular sites, where Tiam1 promotes local Rac1 activation and cytoskeletal remodeling. However, the mechanisms that restrict Par-Tiam1 complex activity to the leading edge to maintain cell polarity during migration remain unclear. We identify the Rac-specific GTPase-activating protein (GAP) breakpoint cluster region protein (Bcr) as a novel regulator of the Par-Tiam1 complex. We show that Bcr interacts with members of the Par complex and inhibits both Rac1 and PKCζ signaling. Loss of Bcr results in faster, more random migration and striking polarity defects in astrocytes. These polarity defects are rescued by reducing PKCζ activity or by expressing full-length Bcr, but not an N-terminal deletion mutant or the homologous Rac-GAP, Abr, both of which fail to associate with the Par complex. These results demonstrate that Bcr is an integral member of the Par-Tiam1 complex that controls polarized cell migration by locally restricting both Rac1 and PKCζ function. PMID:24152735

  3. The RAC1 P29S Hotspot Mutation in Melanoma Confers Resistance to Pharmacological Inhibition of RAF

    PubMed Central

    Cabeceiras, Peter K.; Mahdavi, Mozhdeh; Gutschner, Tony; Genovese, Giannicola; Wang, Guocan; Fang, Zhuangna; Tepper, James M.; Stemke-Hale, Katherine; Tsai, Kenneth Y.; Davies, Michael A.; Mills, Gordon B.

    2014-01-01

    Following mutations in BRAF and NRAS, the RAC1 c.85C>T single nucleotide variant (SNV) encoding P29S amino acid change represents the next most frequently observed protein-coding hotspot mutation in melanoma. However, the biological and clinical significance of the RAC1 P29S somatic mutation in approximately 4–9% of patients remains unclear. Here, we demonstrate that melanoma cell lines possessing the RAC1 hotspot variant are resistant to RAF inhibitors (vemurafenib and dabrafenib). Enforced expression of RAC1 P29S in sensitive BRAF mutant melanoma cell lines confers resistance manifested by increased viability, decreased apoptosis and enhanced tumor growth in vivo upon treatment with RAF inhibitors. Conversely, RNAi mediated silencing of endogenous RAC1 P29S in a melanoma cell line with a co-occurring BRAF V600 mutation increased sensitivity to vemurafenib and dabrafenib. Our results suggest RAC1 P29S status may offer a predictive biomarker for RAF inhibitor resistance in melanoma patients, where it should be evaluated clinically. PMID:25056119

  4. Up-regulated type I collagen expression by the inhibition of Rac1 signaling pathway in human dermal fibroblasts.

    PubMed

    Igata, Toshikatsu; Jinnin, Masatoshi; Makino, Takamitsu; Moriya, Chikako; Muchemwa, Faith C; Ishihara, Tsuyoshi; Ihn, Hironobu

    2010-02-26

    Tissue remodeling is known to play important roles in wound healing. Although Rac1 is reported to be one of the key signaling molecules in cutaneous wound healing process, the exact mechanisms of Rac1-mediated tissue remodeling is still unknown. This study investigated the role of Rac1 in the regulation of extracellular matrix in cultured human dermal fibroblasts obtained by skin biopsy from three healthy donors. Protein levels of type I collagen in cultured human fibroblasts were increased by the treatment with Rac1 inhibitor NSC23766 in a dose-dependent manner. However, the mRNA levels of alpha2(I) collagen was not altered by the inhibitor. On the other hand, by the addition of inhibitor, half-lives of type I collagen protein were increased and MMP1 levels were reduced. These data suggest that blockade of Rac1 signaling results in accumulation of type I collagen due to decreased collagenase activity. This study also suggests that controlling Rac1 signaling is a new therapeutic approach to chronic/untreatable ulcer.

  5. Activation of Rac1-dependent redox signaling is critically involved in staurosporine-induced neurite outgrowth in PC12 cells.

    PubMed

    Kim, Du Sik; An, Jeong Mi; Lee, Han Gil; Seo, Su Ryeon; Kim, Seon Sook; Kim, Ju Yeon; Kang, Jeong Wan; Bae, Yun Soo; Seo, Jeong Taeg

    2013-02-01

    Staurosporine, a non-specific protein kinase inhibitor, has been shown to induce neurite outgrowth in PC12 cells, but the mechanism by which staurosporine induces neurite outgrowth is still obscure. In the present study, we investigated whether the activation of Rac1 was responsible for the neurite outgrowth triggered by staurosporine. Staurosporine caused rapid neurite outgrowth independent of the ERK signaling pathways. In contrast, neurite outgrowth in response to staurosporine was accompanied by activation of Rac1, and the Rac1 inhibitor NSC23766 attenuated the staurosporine-induced neurite outgrowth in a concentration-dependent manner. In addition, suppression of Rac1 activity by expression of the dominant negative mutant Rac1N17 also blocked the staurosporine-induced morphological differentiation of PC12 cells. Staurosporine caused an activation of NADPH oxidase and increased the production of reactive oxygen species (ROS), which was prevented by NSC23766 and diphenyleneiodonium (DPI), an NADPH oxidase inhibitor. Staurosporine-induced neurite outgrowth was attenuated by pretreatment with DPI and exogenous addition of sublethal concentration of H2O2 accelerated neurite outgrowth triggered by staurosporine. These results indicate that activation of Rac1, which leads to ROS generation, is required for neurite outgrowth induced by staurosporine in PC12 cells.

  6. Stereoselective Alkali-Metal Catalysts for Highly Isotactic Poly(rac-lactide) Synthesis.

    PubMed

    Sun, Yangyang; Xiong, Jiao; Dai, Zhongran; Pan, Xiaobo; Tang, Ning; Wu, Jincai

    2016-01-01

    A high degree of chain end control in the isoselective ring-opening polymerization (ROP) of rac-lactide is a challenging research goal. In this work, eight highly active sodium and potassium phenolates as highly isoselective catalysts for the ROP of rac-lactide are reported. The best isoselectivity value of Pm = 0.94 is achieved. The isoselective mechanism is chain-end control through the analysis of the stereoerrors in the microstructure of a final polymer; thus, isotactic multiblock structure polymers are obtained, and the highest melt point can reach 192.5 °C. The donating group in phenolate can clearly accelerate the ROP reaction, potassium complexes are more active than the analogous sodium complexes, and the big spacial hindrance of the ligand can decrease the activity. The high isoselectivities of these complexes mostly result from their sandwich structure constructed by the plane of the crown and the plane of the anthryl group. PMID:26684962

  7. Rac-1 and Raf-1 kinases, components of distinct signaling pathways, activate myotonic dystrophy protein kinase

    NASA Technical Reports Server (NTRS)

    Shimizu, M.; Wang, W.; Walch, E. T.; Dunne, P. W.; Epstein, H. F.

    2000-01-01

    Myotonic dystrophy protein kinase (DMPK) is a serine-threonine protein kinase encoded by the myotonic dystrophy (DM) locus on human chromosome 19q13.3. It is a close relative of other kinases that interact with members of the Rho family of small GTPases. We show here that the actin cytoskeleton-linked GTPase Rac-1 binds to DMPK, and coexpression of Rac-1 and DMPK activates its transphosphorylation activity in a GTP-sensitive manner. DMPK can also bind Raf-1 kinase, the Ras-activated molecule of the MAP kinase pathway. Purified Raf-1 kinase phosphorylates and activates DMPK. The interaction of DMPK with these distinct signals suggests that it may play a role as a nexus for cross-talk between their respective pathways and may partially explain the remarkable pleiotropy of DM.

  8. Plexin-B2 negatively regulates macrophage motility, Rac, and Cdc42 activation.

    PubMed

    Roney, Kelly E; O'Connor, Brian P; Wen, Haitao; Holl, Eda K; Guthrie, Elizabeth H; Davis, Beckley K; Jones, Stephen W; Jha, Sushmita; Sharek, Lisa; Garcia-Mata, Rafael; Bear, James E; Ting, Jenny P-Y

    2011-01-01

    Plexins are cell surface receptors widely studied in the nervous system, where they mediate migration and morphogenesis though the Rho family of small GTPases. More recently, plexins have been implicated in immune processes including cell-cell interaction, immune activation, migration, and cytokine production. Plexin-B2 facilitates ligand induced cell guidance and migration in the nervous system, and induces cytoskeletal changes in overexpression assays through RhoGTPase. The function of Plexin-B2 in the immune system is unknown. This report shows that Plexin-B2 is highly expressed on cells of the innate immune system in the mouse, including macrophages, conventional dendritic cells, and plasmacytoid dendritic cells. However, Plexin-B2 does not appear to regulate the production of proinflammatory cytokines, phagocytosis of a variety of targets, or directional migration towards chemoattractants or extracellular matrix in mouse macrophages. Instead, Plxnb2(-/-) macrophages have greater cellular motility than wild type in the unstimulated state that is accompanied by more active, GTP-bound Rac and Cdc42. Additionally, Plxnb2(-/-) macrophages demonstrate faster in vitro wound closure activity. Studies have shown that a closely related family member, Plexin-B1, binds to active Rac and sequesters it from downstream signaling. The interaction of Plexin-B2 with Rac has only been previously confirmed in yeast and bacterial overexpression assays. The data presented here show that Plexin-B2 functions in mouse macrophages as a negative regulator of the GTPases Rac and Cdc42 and as a negative regulator of basal cell motility and wound healing.

  9. Regulation of valve endothelial cell vasculogenic network architectures with ROCK and Rac inhibitors

    PubMed Central

    Arevalos, C. Alexander; Walborn, Amanda T.; Rupert, Amanda A.; Berg, Jonathan M.; Godfrey, Elizabeth L.; Nguyen, Jacqueline M.V.; Grande-Allen, K. Jane

    2016-01-01

    Objective The age- and disease-dependent presence of microvessels within heart valves is an understudied characteristic of these tissues. Neovascularization involves endothelial cell (EC) migration and cytoskeletal reorientation, which are heavily regulated by the Rho family of GTPases. Given that valve ECs demonstrate unique mesenchymal transdifferentiation and cytoskeletal mechanoresponsiveness, compared to vascular ECs, this study quantified the effect of inhibiting two members of the Rho family on vasculogenic network formation by valve ECs. Approach and results A tubule-like structure vasculogenesis assay (assessing lacunarity, junction density, and vessel density) was performed with porcine aortic valve ECs treated with small molecule inhibitors of Rho-associated serine-threonine protein kinase (ROCK), Y-27632, or the Rac1 inhibitor, NSC-23766. Actin coordination, cell number, and cell migration were assessed through immunocytochemistry, MTT assay, and scratch wound healing assay. ROCK inhibition reduced network lacunarity and interrupted proper cell–cell adhesion and actin coordination. Rac1 inhibition increased lacunarity and delayed actin-mediated network formation. ROCK inhibition alone significantly inhibited migration, whereas both ROCK and Rac1 inhibition significantly reduced cell number over time compared to controls. Compared to a vascular EC line, the valve ECs generated a network with larger total vessel length, but a less smooth appearance. Conclusions Both ROCK and Rac1 inhibition interfered with key processes in vascular network formation by valve ECs. This is the first report of manipulation of valve EC vasculogenic organization in response to small molecule inhibitors. Further study is warranted to comprehend this facet of valvular cell biology and pathology and how it differs from vascular biology. PMID:25660064

  10. GTP-binding proteins of the Rho/Rac family: regulation, effectors and functions in vivo

    PubMed Central

    Bustelo, Xosé R.; Sauzeau, Vincent; Berenjeno, Inmaculada M.

    2007-01-01

    Summary Rho/Rac proteins constitute a subgroup of the Ras superfamily of GTP hydrolases. Although originally implicated in the control of cytoskeletal events, it is currently known that these GTPases coordinate diverse cellular functions, including cell polarity, vesicular trafficking, the cell cycle and transcriptomal dynamics. In this review, we will provide an overview on the recent advances in this field regarding the mechanism of regulation and signaling, and the roles in vivo of this important GTPase family. PMID:17373658

  11. Primary granule exocytosis in human neutrophils is regulated by Rac-dependent actin remodeling.

    PubMed

    Mitchell, Troy; Lo, Andrea; Logan, Michael R; Lacy, Paige; Eitzen, Gary

    2008-11-01

    The actin cytoskeleton regulates exocytosis in all secretory cells. In neutrophils, Rac2 GTPase has been shown to control primary (azurophilic) granule exocytosis. In this report, we propose that Rac2 is required for actin cytoskeletal remodeling to promote primary granule exocytosis. Treatment of neutrophils with low doses (< or = 10 microM) of the actin-depolymerizing drugs latrunculin B (Lat B) or cytochalasin B (CB) enhanced both formyl peptide receptor- and Ca(2+) ionophore-stimulated exocytosis. Higher concentrations of CB or Lat B, or stabilization of F-actin with jasplakinolide (JP), inhibited primary granule exocytosis measured as myeloperoxidase release but did not affect secondary granule exocytosis determined by lactoferrin release. These results suggest an obligatory role for F-actin disassembly before primary granule exocytosis. However, lysates from secretagogue-stimulated neutrophils showed enhanced actin polymerization activity in vitro. Microscopic analysis showed that resting neutrophils contain significant cortical F-actin, which was redistributed to sites of primary granule translocation when stimulated. Exocytosis and actin remodeling was highly polarized when cells were primed with CB; however, polarization was reduced by Lat B preincubation, and both polarization and exocytosis were blocked when F-actin was stabilized with JP. Treatment of cells with the small molecule Rac inhibitor NSC23766 also inhibited actin remodeling and primary granule exocytosis induced by Lat B/fMLF or CB/fMLF, but not by Ca(2+) ionophore. Therefore, we propose a role for F-actin depolymerization at the cell cortex coupled with Rac-dependent F-actin polymerization in the cell cytoplasm to promote primary granule exocytosis.

  12. 48 CFR 970.5244-1 - Contractor purchasing system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 908.7106 (4) Alcohol—48 CFR 908.7107 (5) Helium—48 CFR subpart 8.5 (6) Fuels and packaged petroleum... award of subcontracts consistent with this clause and 48 CFR subpart 970.44. The Contractor's purchasing... Energy (DOE) in accordance with 48 CFR 970.4401-1. The Contractor shall maintain file documentation...

  13. 46 CFR 340.7 - Application to contractors and subcontractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... FOR NATIONAL SECURITY AND NATIONAL DEFENSE RELATED OPERATIONS § 340.7 Application to contractors and... 46 Shipping 8 2010-10-01 2010-10-01 false Application to contractors and subcontractors. 340.7 Section 340.7 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING...

  14. 46 CFR 340.7 - Application to contractors and subcontractors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... FOR NATIONAL SECURITY AND NATIONAL DEFENSE RELATED OPERATIONS § 340.7 Application to contractors and... 46 Shipping 8 2011-10-01 2011-10-01 false Application to contractors and subcontractors. 340.7 Section 340.7 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING...

  15. 48 CFR 2152.215-70 - Contractor records retention.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Notwithstanding the provisions of FAR 52.215-2(f), “Audit and Records—Negotiation,” the Contractor must retain and... Contractor chooses to maintain paper documents in electronic format, the electronic version must be an exact replica of the paper document. (End of clause)...

  16. 48 CFR 1252.242-71 - Contractor testimony.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor testimony. 1252.242-71 Section 1252.242-71 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION CLAUSES... Contractor testimony. As prescribed in (TAR) 48 CFR 1242.7000(b), insert the following clause:...

  17. 48 CFR 1252.242-71 - Contractor testimony.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Contractor testimony. 1252.242-71 Section 1252.242-71 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION CLAUSES... Contractor testimony. As prescribed in (TAR) 48 CFR 1242.7000(b), insert the following clause:...

  18. 48 CFR 52.204-7 - Central Contractor Registration.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (CCR) database means the primary Government repository for Contractor information required for the...) for the same concern. Registered in the CCR database means that— (1) The Contractor has entered all... Federal Funding Accountability and Transparency Act of 2006 (see subpart 4.14), into the CCR database;...

  19. 48 CFR 52.204-7 - Central Contractor Registration.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (CCR) database means the primary Government repository for Contractor information required for the...) for the same concern. Registered in the CCR database means that— (1) The Contractor has entered all mandatory information, including the DUNS number or the DUNS+4 number, into the CCR database; and (2)...

  20. 48 CFR 52.204-7 - Central Contractor Registration.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (CCR) database means the primary Government repository for Contractor information required for the...) for the same concern. Registered in the CCR database means that— (1) The Contractor has entered all mandatory information, including the DUNS number or the DUNS+4 number, into the CCR database; and (2)...

  1. 48 CFR 252.242-7005 - Contractor business systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... regulations found at 48 CFR 9903.201-1 (see the FAR Appendix). (b) Definitions. As used in this clause... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Contractor business... of Provisions And Clauses 252.242-7005 Contractor business systems. As prescribed in 242.7001,...

  2. 48 CFR 242.7000 - Contractor business system deficiencies.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Accounting Standards under 41 U.S.C. chapter 15, as implemented in regulations found at 48 CFR 9903.201-1... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Contractor business system... Business Systems 242.7000 Contractor business system deficiencies. (a) Definitions. As used in this...

  3. 48 CFR 242.7000 - Contractor business system deficiencies.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Accounting Standards under 41 U.S.C. chapter 15, as implemented in regulations found at 48 CFR 9903.201-1... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Contractor business system... BUSINESS SYSTEMS 242.7000 Contractor business system deficiencies. (a) Definitions. As used in this...

  4. 48 CFR 242.7000 - Contractor business system deficiencies.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Accounting Standards under 41 U.S.C. chapter 15, as implemented in regulations found at 48 CFR 9903.201-1... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Contractor business system... BUSINESS SYSTEMS 242.7000 Contractor business system deficiencies. (a) Definitions. As used in this...

  5. 48 CFR 252.242-7005 - Contractor business systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... regulations found at 48 CFR 9903.201-1 (see the FAR Appendix). (b) Definitions. As used in this clause... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Contractor business... of Provisions And Clauses 252.242-7005 Contractor business systems. As prescribed in 242.7001,...

  6. 48 CFR 252.242-7005 - Contractor business systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... regulations found at 48 CFR 9903.201-1 (see the FAR Appendix). (b) Definitions. As used in this clause... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Contractor business... of Provisions And Clauses 252.242-7005 Contractor business systems. As prescribed in 242.7001,...

  7. 48 CFR 242.7000 - Contractor business system deficiencies.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Accounting Standards under 41 U.S.C. chapter 15, as implemented in regulations found at 48 CFR 9903.201-1... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Contractor business system... Business Systems 242.7000 Contractor business system deficiencies. (a) Definitions. As used in this...

  8. 23 CFR 635.110 - Licensing and qualification of contractors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Licensing and qualification of contractors. 635.110... TRAFFIC OPERATIONS CONSTRUCTION AND MAINTENANCE Contract Procedures § 635.110 Licensing and qualification... licensing contractors, who may bid for, be awarded, or perform Federal-aid highway contracts, shall...

  9. 48 CFR 252.244-7001 - Contractor purchasing system administration.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... delivery, quantity, or price; (15) Document and justify reasons for subcontract changes that affect cost or....246-7007, Contractor Counterfeit Electronic Part Detection and Avoidance System, if applicable; (20..., including the requirements of 252.246-7007, Contractor Counterfeit Electronic Part Detection and...

  10. 10 CFR 436.32 - Qualified contractors lists.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Qualified contractors lists. 436.32 Section 436.32 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methods and Procedures for Energy Savings Performance Contracting § 436.32 Qualified contractors lists. (a) DOE...

  11. 10 CFR 436.32 - Qualified contractors lists.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Qualified contractors lists. 436.32 Section 436.32 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methods and Procedures for Energy Savings Performance Contracting § 436.32 Qualified contractors lists. (a) DOE...

  12. 10 CFR 436.32 - Qualified contractors lists.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Qualified contractors lists. 436.32 Section 436.32 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methods and Procedures for Energy Savings Performance Contracting § 436.32 Qualified contractors lists. (a) DOE...

  13. 10 CFR 436.32 - Qualified contractors lists.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Qualified contractors lists. 436.32 Section 436.32 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methods and Procedures for Energy Savings Performance Contracting § 436.32 Qualified contractors lists. (a) DOE...

  14. 10 CFR 436.32 - Qualified contractors lists.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Qualified contractors lists. 436.32 Section 436.32 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methods and Procedures for Energy Savings Performance Contracting § 436.32 Qualified contractors lists. (a) DOE...

  15. 48 CFR 970.4402 - Contractor purchasing system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Contractor purchasing system. 970.4402 Section 970.4402 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Management and Operating Contractor...

  16. 48 CFR 970.4402 - Contractor purchasing system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Contractor purchasing system. 970.4402 Section 970.4402 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Management and Operating Contractor...

  17. 48 CFR 945.671 - Contractor inventory in foreign countries.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Contractor inventory in foreign countries. 945.671 Section 945.671 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CONTRACT MANAGEMENT GOVERNMENT PROPERTY Reporting, Reutilization, and Disposal 945.671 Contractor...

  18. 48 CFR 227.7203-11 - Contractor procedures and records.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Rights in Computer Software and Computer Software Documentation 227.7203-11 Contractor procedures and records. (a) The clause at 252.227-7014, Rights in Noncommercial Computer Software and Noncommercial Computer Software Documentation, requires a contractor, and its subcontractors or suppliers that...

  19. 48 CFR 227.7203-11 - Contractor procedures and records.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Rights in Computer Software and Computer Software Documentation 227.7203-11 Contractor procedures and records. (a) The clause at 252.227-7014, Rights in Noncommercial Computer Software and Noncommercial Computer Software Documentation, requires a contractor, and its subcontractors or suppliers that...

  20. 48 CFR 227.7203-11 - Contractor procedures and records.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Rights in Computer Software and Computer Software Documentation 227.7203-11 Contractor procedures and records. (a) The clause at 252.227-7014, Rights in Noncommercial Computer Software and Noncommercial Computer Software Documentation, requires a contractor, and its subcontractors or suppliers that...

  1. 48 CFR 227.7203-11 - Contractor procedures and records.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Rights in Computer Software and Computer Software Documentation 227.7203-11 Contractor procedures and records. (a) The clause at 252.227-7014, Rights in Noncommercial Computer Software and Noncommercial Computer Software Documentation, requires a contractor, and its subcontractors or suppliers that...

  2. 48 CFR 227.7203-11 - Contractor procedures and records.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Rights in Computer Software and Computer Software Documentation 227.7203-11 Contractor procedures and records. (a) The clause at 252.227-7014, Rights in Noncommercial Computer Software and Noncommercial Computer Software Documentation, requires a contractor, and its subcontractors or suppliers that...

  3. 48 CFR 3052.204-71 - Contractor employee access.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Contractor employee access. 3052.204-71 Section 3052.204-71 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY... CLAUSES Text of Provisions and Clauses 3052.204-71 Contractor employee access. As prescribed in (HSAR)...

  4. 48 CFR 1403.570 - Restrictions on contractor advertising.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Restrictions on contractor advertising. 1403.570 Section 1403.570 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR... 1403.570 Restrictions on contractor advertising....

  5. 48 CFR 227.7108 - Contractor data repositories.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Contractor data repositories. 227.7108 Section 227.7108 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL CONTRACTING REQUIREMENTS PATENTS, DATA, AND COPYRIGHTS Rights in Technical Data 227.7108 Contractor...

  6. 48 CFR 8.406-7 - Contractor Performance Evaluation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Performance Evaluation. Ordering activities must prepare an evaluation of contractor performance for each... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contractor Performance Evaluation. 8.406-7 Section 8.406-7 Federal Acquisition Regulations System FEDERAL ACQUISITION...

  7. 48 CFR 1552.209-76 - Contractor performance evaluations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 1552.209-76 Contractor performance evaluations. As prescribed in section 1509.170-1, insert the following clause in all applicable solicitations and contracts. Contractor Performance Evaluations (OCT 2002... compliance with safety standards performance categories if deemed appropriate for the evaluation or...

  8. 48 CFR 2936.201 - Evaluation of contractor performance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Construction 2936.201 Evaluation of contractor performance. The HCA must establish procedures to evaluate... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Evaluation of contractor performance. 2936.201 Section 2936.201 Federal Acquisition Regulations System DEPARTMENT OF LABOR...

  9. 18 CFR 1308.11 - Contractor's request for relief.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Contractor's request for relief. 1308.11 Section 1308.11 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY CONTRACT DISPUTES Contracting Officers § 1308.11 Contractor's request for relief. Any request...

  10. 48 CFR 923.102 - Applicability to contractors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... contractors. 923.102 Section 923.102 Federal Acquisition Regulations System DEPARTMENT OF ENERGY SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Sustainable Acquisition 923.102 Applicability to contractors. Many of...

  11. 48 CFR 923.102 - Applicability to contractors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... contractors. 923.102 Section 923.102 Federal Acquisition Regulations System DEPARTMENT OF ENERGY SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Sustainable Acquisition 923.102 Applicability to contractors. Many of...

  12. 48 CFR 923.102 - Applicability to contractors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... contractors. 923.102 Section 923.102 Federal Acquisition Regulations System DEPARTMENT OF ENERGY SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Sustainable Acquisition 923.102 Applicability to contractors. Many of...

  13. 48 CFR 923.102 - Applicability to contractors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... contractors. 923.102 Section 923.102 Federal Acquisition Regulations System DEPARTMENT OF ENERGY SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Sustainable Acquisition 923.102 Applicability to contractors. Many of...

  14. 21 CFR 20.90 - Disclosure to contractors.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Disclosure to contractors. 20.90 Section 20.90 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PUBLIC... exempt from public disclosure may be disclosed to contractors with the Food and Drug Administration...

  15. 21 CFR 20.90 - Disclosure to contractors.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Disclosure to contractors. 20.90 Section 20.90 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PUBLIC... exempt from public disclosure may be disclosed to contractors with the Food and Drug Administration...

  16. 21 CFR 20.90 - Disclosure to contractors.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Disclosure to contractors. 20.90 Section 20.90 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PUBLIC... exempt from public disclosure may be disclosed to contractors with the Food and Drug Administration...

  17. 21 CFR 20.90 - Disclosure to contractors.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Disclosure to contractors. 20.90 Section 20.90 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PUBLIC... exempt from public disclosure may be disclosed to contractors with the Food and Drug Administration...

  18. 48 CFR 1552.237-76 - Government-Contractor Relations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses...: Government-Contractor Relations (JUN 1999) (a) The Government and the Contractor understand and agree that... interest of the Government to afford both parties a full understanding of their respective obligations....

  19. 48 CFR 2452.237-75 - Clearance of contractor personnel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Clearance of contractor personnel. 2452.237-75 Section 2452.237-75 Federal Acquisition Regulations System DEPARTMENT OF HOUSING AND...). The Contractor shall provide the GTR with the names and Social Security numbers of all such...

  20. 48 CFR 970.5244-1 - Contractor purchasing system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Energy (DOE) in accordance with 48 CFR 970.4401-1. The Contractor shall maintain file documentation which...-affiliated source shall be purchased or transferred in accordance with 48 CFR 970.4402-3. (j) Contractor... system. 970.5244-1 Section 970.5244-1 Federal Acquisition Regulations System DEPARTMENT OF ENERGY...