Sample records for action contractor rac

  1. How to staff for RACs.

    PubMed

    Brocato, Lori; Hirschl, Nancy; Padfield, Stanley

    2010-01-01

    To meet the challenges presented by recovery audit contractors (RACs), hospitals should perform six tasks that require appropriate investments in staff: conduct a financial risk assessment of the impact of RAC reviews on the organization; establish a RAC team and assign a coordinator; receive and fill RAC requests; track RAC activity; manage RAC appeals; analyze RAC audit outcomes.

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-10

    ... [CMS-6034-P] RIN 0938-AQ19 Medicaid Program; Recovery Audit Contractors AGENCY: Centers for Medicare... Recovery Audit Contractors (Medicaid RACs) and the payment methodology for State payments to Medicaid RACs... RACs coordinate with other contractors and entities auditing Medicaid providers and with State and...

  3. The RAC program: what can radiology providers expect as RACs begin auditing?

    PubMed

    Pendleton, Abby; Gustafson, Jessica L

    2009-01-01

    The Centers for Medicare and Medicaid Services (CMS) Recovery Audit Contractor (RAC) program has been made permanent and is expanding nationwide. Radiology providers should be ready for increased Medicare auditing activity as the RAC expands. Should a provider or supplier be subject to a RAC audit, effective strategies are available that can be successfully employed in the appeals process to challenge denials.

  4. The forecast for RAC extrapolation: mostly cloudy.

    PubMed

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

    2011-09-01

    The current statutory and regulatory guidance for recovery audit contractor (RAC) extrapolation leaves providers with minimal protection against the process and a limited ability to challenge overpayment demands. Providers not only should understand the statutory and regulatory basis for extrapolation forecast, but also should be able to assess their extrapolation risk and their recourse through regulatory safeguards against contractor error. Providers also should aggressively appeal all incorrect RAC denials to minimize the potential impact of extrapolation.

  5. 7 CFR 1924.276 - Action against contractor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS CONSTRUCTION AND REPAIR Complaints and Compensation for Construction Defects § 1924.276 Action... construction defects which are the responsibility of the contractor, debarment proceedings will be initiated... the borrower's claim against the contractor or other party will be obtained if it appears to the...

  6. 7 CFR 1924.276 - Action against contractor.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REGULATIONS CONSTRUCTION AND REPAIR Complaints and Compensation for Construction Defects § 1924.276 Action... construction defects which are the responsibility of the contractor, debarment proceedings will be initiated... the borrower's claim against the contractor or other party will be obtained if it appears to the...

  7. 7 CFR 1924.276 - Action against contractor.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REGULATIONS CONSTRUCTION AND REPAIR Complaints and Compensation for Construction Defects § 1924.276 Action... construction defects which are the responsibility of the contractor, debarment proceedings will be initiated... the borrower's claim against the contractor or other party will be obtained if it appears to the...

  8. 7 CFR 1924.276 - Action against contractor.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REGULATIONS CONSTRUCTION AND REPAIR Complaints and Compensation for Construction Defects § 1924.276 Action... construction defects which are the responsibility of the contractor, debarment proceedings will be initiated... the borrower's claim against the contractor or other party will be obtained if it appears to the...

  9. 7 CFR 1924.276 - Action against contractor.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS CONSTRUCTION AND REPAIR Complaints and Compensation for Construction Defects § 1924.276 Action... construction defects which are the responsibility of the contractor, debarment proceedings will be initiated... the borrower's claim against the contractor or other party will be obtained if it appears to the...

  10. 76 FR 57807 - Medicaid Program; Recovery Audit Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ... for Medicare & Medicaid Services 42 CFR Part 455 Medicaid Program; Recovery Audit Contractors; Final... 42 CFR Part 455 [CMS-6034-F] RIN 0938-AQ19 Medicaid Program; Recovery Audit Contractors AGENCY... costs of Medicaid Recovery Audit Contractors (Medicaid RACs) and the payment methodology for State...

  11. 28 CFR 115.277 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... volunteers. 115.277 Section 115.277 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... Corrective action for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse... contractor or volunteer. ...

  12. 28 CFR 115.277 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... volunteers. 115.277 Section 115.277 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... Corrective action for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse... contractor or volunteer. ...

  13. 28 CFR 115.277 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... volunteers. 115.277 Section 115.277 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... Corrective action for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse... contractor or volunteer. ...

  14. 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 in...

  15. 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 in...

  16. 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 in...

  17. 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 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 in...

  18. 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 in...

  19. 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.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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.

  1. 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.

  2. 76 FR 23357 - Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors Regarding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-26

    ... Contractors and Subcontractors Regarding Protected Veterans; Proposed Rule #0;#0;Federal Register / Vol. 76... Nondiscrimination Obligations of Contractors and Subcontractors Regarding Protected Veterans AGENCY: Office of..., which requires covered Federal contractors and subcontractors to take affirmative action in employment...

  3. 76 FR 36482 - Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors Regarding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... DEPARTMENT OF LABOR Office of Federal Contract Compliance Programs 41 CFR Parts 60-250 and 60-300 RIN 1250-AA00 Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors... Nondiscrimination Obligations of Contractors and Subcontractors Regarding Protected Veterans'' (76 FR 23358). OFCCP...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ...-AA02 Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors Regarding... affirmative action regulations of section 503 of the Rehabilitation Act of 1973, as amended. This document..., OFCCP published a proposed rule entitled, ``Affirmative Action and Nondiscrimination Obligations of...

  5. On the RAC. CIOs must work to make their organization's time with CMS Recovery Audit Contractors as painless as possible.

    PubMed

    Lawrence, Daphne

    2009-01-01

    CIOs should act as a team with HIM and Finance to prepare for RAC audits. CIOs can take the lead in looking at improved coding systems, and can be involved in creating policies and procedures for the hospital's RAC team. RAC is an opportunity to improve documentation, coding and data analysis. RAC appeals will become more common as states share lessons learned. Follow the money and check on claims that are frequently returned.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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.

  7. Dissociation of Rac1(GDP)·RhoGDI Complexes by the Cooperative Action of Anionic Liposomes Containing Phosphatidylinositol 3,4,5-Trisphosphate, Rac Guanine Nucleotide Exchange Factor, and GTP*

    PubMed Central

    Ugolev, Yelena; Berdichevsky, Yevgeny; Weinbaum, Carolyn; Pick, Edgar

    2008-01-01

    Rac plays a pivotal role in the assembly of the superoxide-generating NADPH oxidase of phagocytes. In resting cells, Rac is found in the cytosol in complex with Rho GDP dissociation inhibitor (RhoGDI). NADPH oxidase assembly involves dissociation of the Rac·RhoGDI complex and translocation of Rac to the membrane. We reported that liposomes containing high concentrations of monovalent anionic phospholipids cause Rac·RhoGDI complex dissociation (Ugolev, Y., Molshanski-Mor, S., Weinbaum, C., and Pick, E. (2006) J. Biol. Chem.281 ,19204 -1921916702219). We now designed an in vitro model mimicking membrane phospholipid remodeling during phagocyte stimulation in vivo. We showed that liposomes of “resting cell membrane” composition (less than 20 mol % monovalent anionic phospholipids), supplemented with 1 mol % of polyvalent anionic phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) in conjunction with constitutively active forms of the guanine nucleotide exchange factors (GEFs) for Rac, Trio, or Tiam1 and a non-hydrolyzable GTP analogue, cause dissociation of Rac1(GDP)·RhoGDI complexes, GDP to GTP exchange on Rac1, and binding of Rac1(GTP) to the liposomes. Complexes were not dissociated in the absence of GEF and GTP, and optimal dissociation required the presence of PtdIns(3,4,5)P3 in the liposomes. Dissociation of Rac1(GDP)·RhoGDI complexes was correlated with the affinity of particular GEF constructs, via the N-terminal pleckstrin homology domain, for PtdIns(3,4,5)P3 and involved GEF-mediated GDP to GTP exchange on Rac1. Phagocyte membranes enriched in PtdIns(3,4,5)P3 responded by NADPH oxidase activation upon exposure in vitro to Rac1(GDP)·RhoGDI complexes, p67phox, GTP, and Rac GEF constructs with affinity for PtdIns(3,4,5)P3 at a level superior to that of native membranes. PMID:18505730

  8. 75 FR 52551 - Notice of Utah's Resource Advisory Council (RAC) Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLUT91000-L10400000-PH0000-24-1A] Notice of Utah's Resource Advisory Council (RAC) Meeting AGENCY: Bureau of Land Management, Interior. ACTION.... Department of the Interior, Bureau of Land Management's (BLM) Utah Resource Advisory Council (RAC) will meet...

  9. 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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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.

  10. Rac1 and Rac3 have opposing functions in cell adhesion and differentiation of neuronal cells.

    PubMed

    Hajdo-Milasinović, Amra; Ellenbroek, Saskia I J; van Es, Saskia; van der Vaart, Babet; Collard, John G

    2007-02-15

    Rac1 and Rac3 are highly homologous members of the Rho small GTPase family. Rac1 is ubiquitously expressed and regulates cell adhesion, migration and differentiation in various cell types. Rac3 is primarily expressed in brain and may therefore have a specific function in neuronal cells. We found that depletion of Rac1 by short interference RNA leads to decreased cell-matrix adhesions and cell rounding in neuronal N1E-115 cells. By contrast, depletion of Rac3 induces stronger cell adhesions and dramatically increases the outgrowth of neurite-like protrusions, suggesting opposite functions for Rac1 and Rac3 in neuronal cells. Consistent with this, overexpression of Rac1 induces cell spreading, whereas overexpression of Rac3 results in a contractile round morphology. Rac1 is mainly found at the plasma membrane, whereas Rac3 is predominantly localized in the perinuclear region. Residues 185-187, present in the variable polybasic rich region at the carboxyl terminus are responsible for the difference in phenotype induced by Rac1 and Rac3 as well as for their different intracellular localization. The Rac1-opposing function of Rac3 is not mediated by or dependent on components of the RhoA signaling pathway. It rather seems that Rac3 exerts its function through negatively affecting integrin-mediated cell-matrix adhesions. Together, our data reveal that Rac3 opposes Rac1 in the regulation of cell adhesion and differentiation of neuronal cells.

  11. 76 FR 39015 - Contractor Performance Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-05

    ...] Contractor Performance Information AGENCY: Environmental Protection Agency (EPA), ACTION: Direct final rule... contractor performance information. EPA is issuing a final rule because the changes are procedural in nature... Institutes of Health's Contractor Performance System (CPS) to the Department of Defense's Contractor...

  12. Recovery Audit Contractor audits and appeals at three academic medical centers.

    PubMed

    Sheehy, Ann M; Locke, Charles; Engel, Jeannine Z; Weissburg, Daniel J; Mackowiak, Stephanie; Caponi, Bartho; Gangireddy, Sreedevi; Deutschendorf, Amy

    2015-04-01

    Outpatient (observation) and inpatient status determinations for hospitalized Medicare beneficiaries have generated increasing concern for hospitals and patients. Recovery Audit Contractor (RAC) activity alleging improper status, however, has received little attention, and there are conflicting federal and hospital reports of RAC activity and hospital appeals success. To detail complex Medicare Part A RAC activity. Retrospective descriptive study of complex Medicare Part A audits at 3 academic hospitals from 2010 to 2013. Complex Part A audits, outcome of audits, and hospital workforce required to manage this process. Of 101,862 inpatient Medicare encounters, RACs audited 8110 (8.0%) encounters, alleged overpayment in 31.3% (2536/8110), and hospitals disputed 91.0% (2309/2536). There was a nearly 3-fold increase in RAC overpayment determinations in 2 years, although the hospitals contested and won a larger percent of cases each year. One-third (645/1935, 33.3%) of settled claims were decided in the discussion period, which are favorable decisions for the hospitals not reported in federal appeals data. Almost half (951/1935, 49.1%) of settled contested cases were withdrawn by the hospitals and rebilled under Medicare Part B to avoid the lengthy (mean 555 [SD 255] days) appeals process. These original inpatient claims are considered improper payments recovered by the RAC. The hospitals also lost appeals (0.9%) by missing a filing deadline, yet there was no reciprocal case concession when the appeals process missed a deadline. No overpayment determinations contested the need for care delivered, rather that care should have been delivered under outpatient, not inpatient, status. The institutions employed an average 5.1 full-time staff in the audits process. These findings suggest a need for RAC reform, including improved transparency in data reporting. © 2015 Society of Hospital Medicine.

  13. 38 CFR 46.8 - Independent contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Independent contractors... contractors. Independent contractors acting on behalf of the Department of Veterans Affairs are subject to the... provide the contractor with notice that a report of a clinical privileges action will be filed with the...

  14. 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.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26530864

  16. 29 CFR 500.41 - Farm labor contractor is responsible for actions of his farm labor contractor employee.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., prior to such employee's engagement in any activity enumerated in section 3(6) of the Act. A farm labor... farm labor contractor employee. 500.41 Section 500.41 Labor Regulations Relating to Labor (Continued... PROTECTION Registration of Farm Labor Contractors and Employees of Farm Labor Contractors Engaged in Farm...

  17. 29 CFR 500.41 - Farm labor contractor is responsible for actions of his farm labor contractor employee.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., prior to such employee's engagement in any activity enumerated in section 3(6) of the Act. A farm labor... farm labor contractor employee. 500.41 Section 500.41 Labor Regulations Relating to Labor (Continued... PROTECTION Registration of Farm Labor Contractors and Employees of Farm Labor Contractors Engaged in Farm...

  18. 40 CFR 35.6600 - Contractor claims.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Contractor claims. 35.6600 Section 35... Actions Procurement Requirements Under A Cooperative Agreement § 35.6600 Contractor claims. (a) General... prepared by the contractor to support a claim against the recipient; and (4) The award official determines...

  19. 28 CFR 115.77 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... volunteers. 115.77 Section 115.77 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be... other violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

  20. 28 CFR 115.177 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... volunteers. 115.177 Section 115.177 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be prohibited... violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

  1. 28 CFR 115.177 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... volunteers. 115.177 Section 115.177 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be prohibited... violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... volunteers. 115.77 Section 115.77 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be... other violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

  3. 28 CFR 115.77 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... volunteers. 115.77 Section 115.77 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be... other violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

  4. 28 CFR 115.177 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... volunteers. 115.177 Section 115.177 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be prohibited... violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

  5. 28 CFR 115.377 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... volunteers. 115.377 Section 115.377 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be... any other violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

  6. 28 CFR 115.377 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... volunteers. 115.377 Section 115.377 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be... any other violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

  7. 28 CFR 115.377 - Corrective action for contractors and volunteers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... volunteers. 115.377 Section 115.377 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PRISON RAPE... for contractors and volunteers. (a) Any contractor or volunteer who engages in sexual abuse shall be... any other violation of agency sexual abuse or sexual harassment policies by a contractor or volunteer. ...

  8. 48 CFR 450.303-1 - Contractor requests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Contractor requests. 450.303-1 Section 450.303-1 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS Contract Adjustments 450.303-1 Contractor requests. Contractor...

  9. 41 CFR 60-741.68 - Reinstatement of ineligible contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ineligible contractors. 60-741.68 Section 60-741.68 Public Contracts and Property Management Other Provisions..., DEPARTMENT OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... Reinstatement of ineligible contractors. (a) Application for reinstatement. A contractor debarred from further...

  10. 41 CFR 60-300.68 - Reinstatement of ineligible contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ineligible contractors. 60-300.68 Section 60-300.68 Public Contracts and Property Management Other Provisions..., DEPARTMENT OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... ineligible contractors. (a) Application for reinstatement. A contractor debarred from further contracts for...

  11. 41 CFR 60-250.68 - Reinstatement of ineligible contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ineligible contractors. 60-250.68 Section 60-250.68 Public Contracts and Property Management Other Provisions..., DEPARTMENT OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... ineligible contractors. (a) Application for reinstatement. A contractor debarred from further contracts for...

  12. 42 CFR 455.202 - Limitation on contractor liability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Limitation on contractor liability. 455.202 Section... § 455.202 Limitation on contractor liability. (a) A program contractor, a person, or an entity employed... contractor will not be held to have violated any criminal law and will not be held liable in any civil action...

  13. Carboxyl-terminal isoprenylation of ras-related GTP-binding proteins encoded by rac1, rac2, and ralA.

    PubMed

    Kinsella, B T; Erdman, R A; Maltese, W A

    1991-05-25

    Membrane localization of p21ras is dependent upon its posttranslational modification by a 15-carbon farnesyl group. The isoprenoid is linked to a cysteine located within a conserved carboxyl-terminal sequence termed the "CAAX" box (where C is cysteine, A is an aliphatic amino acid, and X is any amino acid). We now show that three GTP-binding proteins encoded by the recently identified rac1, rac2, and ralA genes also undergo isoprenoid modification. cDNAs coding for each protein were transcribed in vitro, and the RNAs were translated in reticulocyte lysates. Incorporation of isoprenoid precursors, [3H]mevalonate or [3H]farnesyl pyrophosphate, indicated that the translation products were modified by isoprenyl groups. A protein recognized by an antibody to rac1 also comigrated with a protein metabolically labeled by a product of [3H] mevalonate in cultured cells. Gel permeation chromatography of radiolabeled hydrocarbons released from the rac1, rac2, and ralA proteins by reaction with Raney nickel catalyst indicated that unlike p21Hras, which was modified by a 15-carbon moiety, the rac and ralA translation products were modified by 20-carbon isoprenyl groups. Site-directed mutagenesis established that the isoprenylated cysteines in the rac1, rac2, and ralA proteins were located in the fourth position from the carboxyl terminus. The three-amino acid extension distal to the cysteine was required for this modification. The isoprenylation of rac1 (CSLL), ralA (CCIL), and the site-directed mutants rac1 (CRLL) and ralA (CSIL), demonstrates that the amino acid adjacent to the cysteine need not be aliphatic. Therefore, proteins with carboxyl-terminal CXXX sequences that depart from the CAAX motif should be considered as potential targets for isoprenoid modification.

  14. The Contractor's Role in Competitive Bid Construction.

    ERIC Educational Resources Information Center

    Toy, G. Arlan

    1986-01-01

    In a competitive bid situation, the general contractor's first priority is controlling construction costs. The actions the general contractor take focus on adequate control, effective communication, efficient use of resources, and prevention of delays. (MLF)

  15. 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

  16. Rac1 Is Required for Cardiomyocyte Apoptosis During Hyperglycemia

    PubMed Central

    Shen, E.; Li, Yanwen; Li, Ying; Shan, Limei; Zhu, Huaqing; Feng, Qingping; Arnold, J. Malcolm O.; Peng, Tianqing

    2009-01-01

    OBJECTIVE Hyperglycemia induces reactive oxygen species (ROS) and apoptosis in cardiomyocytes, which contributes to diabetic cardiomyopathy. The present study was to investigate the role of Rac1 in ROS production and cardiomyocyte apoptosis during hyperglycemia. RESEARCH DESIGN AND METHODS Mice with cardiomyocyte-specific Rac1 knockout (Rac1-ko) were generated. Hyperglycemia was induced in Rac1-ko mice and their wild-type littermates by injection of streptozotocin (STZ). In cultured adult rat cardiomyocytes, apoptosis was induced by high glucose. RESULTS The results showed a mouse model of STZ-induced diabetes, 7 days of hyperglycemia-upregulated Rac1 and NADPH oxidase activation, elevated ROS production, and induced apoptosis in the heart. These effects of hyperglycemia were significantly decreased in Rac1-ko mice or wild-type mice treated with apocynin. Interestingly, deficiency of Rac1 or apocynin treatment significantly reduced hyperglycemia-induced mitochondrial ROS production in the heart. Deficiency of Rac1 also attenuated myocardial dysfunction after 2 months of STZ injection. In cultured cardiomyocytes, high glucose upregulated Rac1 and NADPH oxidase activity and induced apoptotic cell death, which were blocked by overexpression of a dominant negative mutant of Rac1, knockdown of gp91phox or p47phox, or NADPH oxidase inhibitor. In type 2 diabetic db/db mice, administration of Rac1 inhibitor, NSC23766, significantly inhibited NADPH oxidase activity and apoptosis and slightly improved myocardial function. CONCLUSIONS Rac1 is pivotal in hyperglycemia-induced apoptosis in cardiomyocytes. The role of Rac1 is mediated through NADPH oxidase activation and associated with mitochondrial ROS generation. Our study suggests that Rac1 may serve as a potential therapeutic target for cardiac complications of diabetes. PMID:19592621

  17. cDNA cloning, expression and immune function analysis of a novel Rac1 gene (AjRac1) in the sea cucumber Apostichopus japonicus.

    PubMed

    Li, Kaiquan; Liu, Lin; Shang, Shengnan; Wang, Yi; Zhan, Yaoyao; Song, Jian; Zhang, Xiangxiang; Chang, Yaqing

    2017-10-01

    The ras-related C3 botulinum toxin substrate 1 (Rac1) belongs to Ras homolog (Rho) small GTPases subfamily. As an important molecular switch, Rac1 regulates various processes in the cell, especially in cellular immune response. With attempt to clarify characters and functions of Rac1 in sea cucumbers, full length cDNA of a Rac1 homolog in the sea cucumber Apostichopus japonicus (AjRac1) was cloned by transcriptome database mining and rapid amplification of cDNA ends (RACE) techniques. The open reading frame of AjRac1 is 579 bp encoding a protein with a length of 192 aa. Sequence analysis showed that AjRac1 is highly conserved as compared to those from other eukaryotic species. Phylogenetic analysis revealed that amino acid sequence of AjRac1 closely related to those from Strongylocentrotus purpuratus. Results of expression analysis showed that AjRac1 exhibited a relative high expression in blastula stage, adult coelomocytes and respiratory tree in A. japonicus. The transcription of AjRac1 in adult coelomocytes altered significantly at 4 h- and 12 h-after Vibrio splendidus infection, respectively, which indicated that AjRac1 involved in sea cucumber innate immunity. All data presented in this study will deepen our understanding of characterizations and immunological functions of Rac1 in sea cucumbers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. 42 CFR 455.510 - Payments to RACs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false Payments to RACs. 455.510 Section 455.510 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....510 Payments to RACs. (a) General. Fees paid to RACs must be made only from amounts recovered. (b...

  19. Dosage-dependent role of Rac1 in podocyte injury.

    PubMed

    Wan, Xiaoyang; Lee, Mi-Sun; Zhou, Weibin

    2016-04-15

    Activation of small GTPase Rac1 in podocytes is associated with rodent models of kidney injury and familial nephrotic syndrome. Induced Rac1 activation in podocytes in transgenic mice results in rapid transient proteinuria and foot process effacement, but not glomerular sclerosis. Thus it remains an open question whether abnormal activation of Rac1 in podocytes is sufficient to cause permanent podocyte damage. Using a number of transgenic zebrafish models, we showed that moderate elevation of Rac1 activity in podocytes did not impair the glomerular filtration barrier but aggravated metronidazole-induced podocyte injury, while inhibition of Rac1 activity ameliorated metronidazole-induced podocyte injury. Furthermore, a further increase in Rac1 activity in podocytes was sufficient to cause proteinuria and foot process effacement, which resulted in edema and lethality in juvenile zebrafish. We also found that activation of Rac1 in podocytes significantly downregulated the expression of nephrin and podocin , suggesting an adverse effect of Rac1 on slit diaphragm protein expression. Taken together, our data have demonstrated a causal link between excessive Rac1 activity and podocyte injury in a dosage-dependent manner, and transgenic zebrafish of variable Rac1 activities in podocytes may serve as useful animal models for the study of Rac1-related podocytopathy. Copyright © 2016 the American Physiological Society.

  20. 78 FR 25795 - Contractor Legal Management Requirements; Acquisition Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ... DEPARTMENT OF ENERGY 10 CFR Part 719 48 CFR Parts 931, 952, and 970 RIN 1990-AA37 Contractor Legal.... ACTION: Final rule. SUMMARY: The Department of Energy revises existing regulations covering contractor... costs by certain contractors whose contracts exceed $100,000,000 as well as legal counsel retained...

  1. 78 FR 1256 - Guam Military Base Realignment Contractor Recruitment Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-08

    ... Contractor Recruitment Standards AGENCY: Employment and Training Administration, Labor. ACTION: Final notice... issuing this notice to announce recruitment standards that construction contractors are required to follow... B) by adding a new subsection (6). This provision prohibits contractors engaged in construction...

  2. 77 FR 3503 - Guam Military Base Realignment Contractor Recruitment Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-24

    ... Contractor Recruitment Standards AGENCY: Employment and Training Administration, Labor. ACTION: Notice... issuing this notice to announce the recruitment standards that construction contractors are required to... contractors engaged in construction projects related to the realignment of U.S. military forces from Okinawa...

  3. Rac1 Dosage Is Crucial for Normal Endochondral Bone Growth.

    PubMed

    Suzuki, Dai; Bush, Jason R; Bryce, Dawn-Marie; Kamijo, Ryutaro; Beier, Frank

    2017-10-01

    Rac1, a member of the small Rho GTPase family, plays multiple cellular roles. Studies of mice conditionally lacking Rac1 have revealed essential roles for Rac1 in various tissues, including cartilage and limb mesenchyme, where Rac1 loss produces dwarfism and long bone shortening. To gain further insight into the role of Rac1 in skeletal development, we have used transgenic mouse lines to express a constitutively active (ca) Rac1 mutant protein in a Cre recombinase-dependent manner. Overexpression of caRac1 in limb bud mesenchyme or chondrocytes leads to reduced body weight and shorter bones compared with control mice. Histological analysis of growth plates showed that caRac1;Col2-Cre mice displayed ectopic hypertrophic chondrocytes in the proliferative zone and enlarged hypertrophic zones. These mice also displayed a reduced proportion of proliferating cell nuclear antigen-positive cells in the proliferative zone and nuclear β-catenin localization in the ectopic hypertrophic chondrocytes. Importantly, overexpression of caRac1 partially rescued the phenotypes of Rac1fl/fl;Col2-Cre and Rac1fl/fl;Prx1-Cre conditional knockout mice, including body weight, bone length, and growth plate disorganization. These results suggest that tight regulation of Rac1 activity is necessary for normal cartilage development. Copyright © 2017 Endocrine Society.

  4. Pak and Rac GTPases promote oncogenic KIT–induced neoplasms

    PubMed Central

    Martin, Holly; Mali, Raghuveer Singh; Ma, Peilin; Chatterjee, Anindya; Ramdas, Baskar; Sims, Emily; Munugalavadla, Veerendra; Ghosh, Joydeep; Mattingly, Ray R.; Visconte, Valeria; Tiu, Ramon V.; Vlaar, Cornelis P.; Dharmawardhane, Suranganie; Kapur, Reuben

    2013-01-01

    An acquired somatic mutation at codon 816 in the KIT receptor tyrosine kinase is associated with poor prognosis in patients with systemic mastocytosis and acute myeloid leukemia (AML). Treatment of leukemic cells bearing this mutation with an allosteric inhibitor of p21–activated kinase (Pak) or its genetic inactivation results in growth repression due to enhanced apoptosis. Inhibition of the upstream effector Rac abrogates the oncogene-induced growth and activity of Pak. Although both Rac1 and Rac2 are constitutively activated via the guanine nucleotide exchange factor (GEF) Vav1, loss of Rac1 or Rac2 alone moderately corrected the growth of KIT-bearing leukemic cells, whereas the combined loss resulted in 75% growth repression. In vivo, the inhibition of Vav or Rac or Pak delayed the onset of myeloproliferative neoplasms (MPNs) and corrected the associated pathology in mice. To assess the role of Rac GEFs in oncogene-induced transformation, we used an inhibitor of Rac, EHop-016, which specifically targets Vav1 and found that EHop-016 was a potent inhibitor of human and murine leukemic cell growth. These studies identify Pak and Rac GTPases, including Vav1, as potential therapeutic targets in MPN and AML involving an oncogenic form of KIT. PMID:24091327

  5. 10 CFR 824.16 - Direction to NNSA contractors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Direction to NNSA contractors. 824.16 Section 824.16 Energy DEPARTMENT OF ENERGY PROCEDURAL RULES FOR THE ASSESSMENT OF CIVIL PENALTIES FOR CLASSIFIED... the following actions that direct NNSA contractors or subcontractors. (1) Subpoenas; (2) Orders to...

  6. The GTPase Rac-1 controls cell fate in the thymus by diverting thymocytes from positive to negative selection.

    PubMed

    Gomez, M; Kioussis, D; Cantrell, D A

    2001-11-01

    The positive selection of CD4 or CD8 single-positive mature peripheral T lymphocytes and the deletion of self-reactive cells are crucial for central tolerance in the peripheral immune system. Previously, the guanine nucleotide binding protein Rac-1 has been shown to control pre-T cell development. The present report now describes the actions of Rac-1 in thymocyte selection. The study reveals that this molecule has the striking and unique ability to efficiently divert cells from positive selection into a pathway of negative selection and deletion. The ability of Rac-1 to switch thymocytes from a destiny of positive to negative selection identifies this molecule as a critical regulator of the developmental processes in T cells that are essential for immune homeostasis.

  7. Repression of YdaS Toxin Is Mediated by Transcriptional Repressor RacR in the Cryptic rac Prophage of Escherichia coli K-12.

    PubMed

    Krishnamurthi, Revathy; Ghosh, Swagatha; Khedkar, Supriya; Seshasayee, Aswin Sai Narain

    2017-01-01

    Horizontal gene transfer is a major driving force behind the genomic diversity seen in prokaryotes. The cryptic rac prophage in Escherichia coli K-12 carries the gene for a putative transcription factor RacR, whose deletion is lethal. We have shown that the essentiality of racR in E. coli K-12 is attributed to its role in transcriptionally repressing toxin gene(s) called ydaS and ydaT , which are adjacent to and coded divergently to racR . IMPORTANCE Transcription factors in the bacterium E. coli are rarely essential, and when they are essential, they are largely toxin-antitoxin systems. While studying transcription factors encoded in horizontally acquired regions in E. coli , we realized that the protein RacR, a putative transcription factor encoded by a gene on the rac prophage, is an essential protein. Here, using genetics, biochemistry, and bioinformatics, we show that its essentiality derives from its role as a transcriptional repressor of the ydaS and ydaT genes, whose products are toxic to the cell. Unlike type II toxin-antitoxin systems in which transcriptional regulation involves complexes of the toxin and antitoxin, repression by RacR is sufficient to keep ydaS transcriptionally silent.

  8. 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

  9. 10 CFR 820.13 - Direction to NNSA contractors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Direction to NNSA contractors. 820.13 Section 820.13 Energy DEPARTMENT OF ENERGY PROCEDURAL RULES FOR DOE NUCLEAR ACTIVITIES General § 820.13 Direction to..., issues and serves the following actions that direct NNSA contractors: (1) Subpoenas; (2) Orders to compel...

  10. 10 CFR 851.45 - Direction to NNSA contractors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Direction to NNSA contractors. 851.45 Section 851.45 Energy DEPARTMENT OF ENERGY WORKER SAFETY AND HEALTH PROGRAM Enforcement Process § 851.45 Direction to... than the Director, signs, issues and serves the following actions that direct NNSA contractors: (1...

  11. Rac1 modulates cardiomyocyte adhesion during mouse embryonic development

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Abu-Issa, Radwan, E-mail: rabuissa@umich.edu

    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 normallymore » 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.« less

  12. 77 FR 13153 - Information Collection; NASA Contractor Financial Management Reports

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-05

    ..., [email protected] . SUPPLEMENTARY INFORMATION: I. Abstract The NASA Contractor Financial Management... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice 12-019] Information Collection; NASA Contractor Financial Management Reports AGENCY: National Aeronautics and Space Administration (NASA). ACTION...

  13. 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.

  14. 77 FR 52107 - Air Traffic Data in the Possession of Government Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-28

    ... Government Contractors AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice. SUMMARY: The... possession of government contractors providing operational services to the FAA. This notice specifies how and... contractors. SUPPLEMENTARY INFORMATION: A. Background On August 3, 2012, the Pilot's Bill of Rights, Public...

  15. 76 FR 4343 - Agency Information Collection Activities; Proposed Collection; Comment Request; Contractor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ...; Contractor Conflicts of Interest AGENCY: Environmental Protection Agency. ACTION: Notice. SUMMARY: In... control numbers in certain EPA regulations is consolidated in 40 CFR part 9. Abstract: EPA contractors... cleanup and enforcement and because its contractors are often involved in both activities, it is...

  16. 75 FR 27703 - Humboldt Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-18

    ... Community Self-Determination Act (Pub. L. 110- 343) and in compliance with the Federal Advisory Committee... Federal Official and RAC Coordinator roles; (5) selection of RAC Chair; (6) next meeting agenda, location...

  17. 76 FR 24854 - Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-03

    ... DEPARTMENT OF AGRICULTURE Forest Service Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: Pursuant to the authorities in the Federal Advisory Committees Act (Pub. L. 92-463), the Northeast Oregon...

  18. 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

    ... DEPARTMENT OF AGRICULTURE Forest Service Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: Pursuant to the authorities in the Federal Advisory Committees Act (Pub. L. 92-463), the Northeast Oregon...

  19. 75 FR 33241 - Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... DEPARTMENT OF AGRICULTURE Forest Service Notice of a Meeting of the Northeast Oregon Forests Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: Pursuant to the authorities in the Federal Advisory Committees Act (Pub. L. 92-463), the Northeast Oregon...

  20. 78 FR 29247 - Contractor Legal Management Requirements; Acquisition Regulations; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-20

    ... DEPARTMENT OF ENERGY 48 CFR Part 952 RIN 1990-AA37 Contractor Legal Management Requirements; Acquisition Regulations; Correction AGENCY: Department of Energy. ACTION: Final rule; correction. SUMMARY: The... (78 FR 25795). In this document, DOE revised existing regulations covering contractor legal management...

  1. CYK-4 regulates Rac, but not Rho, during cytokinesis

    PubMed Central

    Zhuravlev, Yelena; Hirsch, Sophia M.; Jordan, Shawn N.; Dumont, Julien; Shirasu-Hiza, Mimi; Canman, Julie C.

    2017-01-01

    Cytokinesis is driven by constriction of an actomyosin contractile ring that is controlled by Rho-family small GTPases. Rho, activated by the guanine-nucleotide exchange factor ECT-2, is upstream of both myosin-II activation and diaphanous formin-mediated filamentous actin (f-actin) assembly, which drive ring constriction. The role for Rac and its regulators is more controversial, but, based on the finding that Rac inactivation can rescue cytokinesis failure when the GTPase-activating protein (GAP) CYK-4 is disrupted, Rac activity was proposed to be inhibitory to contractile ring constriction and thus specifically inactivated by CYK-4 at the division plane. An alternative model proposes that Rac inactivation generally rescues cytokinesis failure by reducing cortical tension, thus making it easier for the cell to divide when ring constriction is compromised. In this alternative model, CYK-4 was instead proposed to activate Rho by binding ECT-2. Using a combination of time-lapse in vivo single-cell analysis and Caenorhabditis elegans genetics, our evidence does not support this alternative model. First, we found that Rac disruption does not generally rescue cytokinesis failure: inhibition of Rac specifically rescues cytokinesis failure due to disruption of CYK-4 or ECT-2 but does not rescue cytokinesis failure due to disruption of two other contractile ring components, the Rho effectors diaphanous formin and myosin-II. Second, if CYK-4 regulates cytokinesis through Rho rather than Rac, then CYK-4 inhibition should decrease levels of downstream targets of Rho. Inconsistent with this, we found no change in the levels of f-actin or myosin-II at the division plane when CYK-4 GAP activity was reduced, suggesting that CYK-4 is not upstream of ECT-2/Rho activation. Instead, we found that the rescue of cytokinesis in CYK-4 mutants by Rac inactivation was Cdc42 dependent. Together our data suggest that CYK-4 GAP activity opposes Rac (and perhaps Cdc42) during cytokinesis

  2. 77 FR 29635 - Access to Confidential Business Information by Several Student Services Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-18

    ... 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...? Under Order Number EP-12-H-000389, a Student Services contractor will assist the Office of Science...

  3. American Academy of Physical Medicine and Rehabilitation

    MedlinePlus

    ... Inspector General DMEPOS, RACs, MACs, and other CMS contractor activity Research Advocacy State Affairs and Legislation Tracking ... Inspector General DMEPOS, RACs, MACs, and other CMS contractor activity Research Advocacy State Affairs and Legislation Tracking ...

  4. Physiatrist: What Is a Physiatrist?

    MedlinePlus

    ... Inspector General DMEPOS, RACs, MACs, and other CMS contractor activity Research Advocacy Academy Efforts Coalitions Position Statements ... Inspector General DMEPOS, RACs, MACs, and other CMS contractor activity Research Advocacy Academy Efforts Coalitions Position Statements ...

  5. In situ detection of the activation of Rac1 and RalA small GTPases in mouse adipocytes by immunofluorescent microscopy following in vivo and ex vivo insulin stimulation.

    PubMed

    Takenaka, Nobuyuki; Nihata, Yuma; Ueda, Sho; Satoh, Takaya

    2017-11-01

    Rac1 has been implicated in insulin-dependent glucose uptake by mechanisms involving plasma membrane translocation of the glucose transporter GLUT4 in skeletal muscle. Although the uptake of glucose is also stimulated by insulin in adipose tissue, the role for Rac1 in adipocyte insulin signaling remains controversial. As a step to reveal the role for Rac1 in adipocytes, we aimed to establish immunofluorescent microscopy to detect the intracellular distribution of activated Rac1. The epitope-tagged Rac1-binding domain of a Rac1-specific target was utilized as a probe that specifically recognizes the activated form of Rac1. Rac1 activation in response to ex vivo and in vivo insulin stimulations in primary adipocyte culture and mouse white adipose tissue, respectively, was successfully observed by immunofluorescent microscopy. These Rac1 activations were mediated by phosphoinositide 3-kinase. Another small GTPase RalA has also been implicated in insulin-stimulated glucose uptake in skeletal muscle and adipose tissue. Similarly to Rac1, immunofluorescent microscopy using an activated RalA-specific polypeptide probe allowed us to detect intracellular distribution of insulin-activated RalA in adipocytes. These novel approaches to visualize the activation status of small GTPases in adipocytes will largely contribute to the understanding of signal transduction mechanisms particularly for insulin action. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. The Phosphatidylinositol (3,4,5)-Trisphosphate-dependent Rac Exchanger 1·Ras-related C3 Botulinum Toxin Substrate 1 (P-Rex1·Rac1) Complex Reveals the Basis of Rac1 Activation in Breast Cancer Cells.

    PubMed

    Lucato, Christina M; Halls, Michelle L; Ooms, Lisa M; Liu, Heng-Jia; Mitchell, Christina A; Whisstock, James C; Ellisdon, Andrew M

    2015-08-21

    The P-Rex (phosphatidylinositol (3,4,5)-trisphosphate (PIP3)-dependent Rac exchanger) family (P-Rex1 and P-Rex2) of the Rho guanine nucleotide exchange factors (Rho GEFs) activate Rac GTPases to regulate cell migration, invasion, and metastasis in several human cancers. The family is unique among Rho GEFs, as their activity is regulated by the synergistic binding of PIP3 and Gβγ at the plasma membrane. However, the molecular mechanism of this family of multi-domain proteins remains unclear. We report the 1.95 Å crystal structure of the catalytic P-Rex1 DH-PH tandem domain in complex with its cognate GTPase, Rac1 (Ras-related C3 botulinum toxin substrate-1). Mutations in the P-Rex1·Rac1 interface revealed a critical role for this complex in signaling downstream of receptor tyrosine kinases and G protein-coupled receptors. The structural data indicated that the PIP3/Gβγ binding sites are on the opposite surface and markedly removed from the Rac1 interface, supporting a model whereby P-Rex1 binding to PIP3 and/or Gβγ releases inhibitory C-terminal domains to expose the Rac1 binding site. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Dynamic Control of Excitatory Synapse Development by a Rac1 GEF/GAP Regulatory Complex

    PubMed Central

    Um, Kyongmi; Niu, Sanyong; Duman, Joseph G.; Cheng, Jinxuan; Tu, Yen-Kuei; Schwechter, Brandon; Liu, Feng; Hiles, Laura; Narayanan, Anjana; Ash, Ryan T.; Mulherkar, Shalaka; Alpadi, Kannan; Smirnakis, Stelios M.; Tolias, Kimberley F.

    2014-01-01

    SUMMARY The small GTPase Rac1 orchestrates actin-dependent remodeling essential for numerous cellular processes including synapse development. While precise spatiotemporal regulation of Rac1 is necessary for its function, little is known about the mechanisms that enable Rac1 activators (GEFs) and inhibitors (GAPs) to act in concert to regulate Rac1 signaling. Here we identify a regulatory complex composed of a Rac-GEF (Tiam1) and a Rac-GAP (Bcr) that cooperate to control excitatory synapse development. Disruption of Bcr function within this complex increases Rac1 activity and dendritic spine remodeling, resulting in excessive synaptic growth that is rescued by Tiam1 inhibition. Notably, EphB receptors utilize the Tiam1-Bcr complex to control synaptogenesis. Following EphB activation, Tiam1 induces Rac1-dependent spine formation, whereas Bcr prevents Rac1-mediated receptor internalization, promoting spine growth over retraction. The finding that a Rac-specific GEF/GAP complex is required to maintain optimal levels of Rac1 signaling provides an important insight into the regulation of small GTPases. PMID:24960694

  8. RCP-driven α5β1 recycling suppresses Rac and promotes RhoA activity via the RacGAP1-IQGAP1 complex.

    PubMed

    Jacquemet, Guillaume; Green, David M; Bridgewater, Rebecca E; von Kriegsheim, Alexander; Humphries, Martin J; Norman, Jim C; Caswell, Patrick T

    2013-09-16

    Inhibition of αvβ3 or expression of mutant p53 promotes invasion into fibronectin (FN)-containing extracellular matrix (ECM) by enhancing Rab-coupling protein (RCP)-dependent recycling of α5β1 integrin. RCP and α5β1 cooperatively recruit receptor tyrosine kinases, including EGFR1, to regulate their trafficking and downstream signaling via protein kinase B (PKB)/Akt, which, in turn, promotes invasive migration. In this paper, we identify a novel PKB/Akt substrate, RacGAP1, which is phosphorylated as a consequence of RCP-dependent α5β1 trafficking. Phosphorylation of RacGAP1 promotes its recruitment to IQGAP1 at the tips of invasive pseudopods, and RacGAP1 then locally suppresses the activity of the cytoskeletal regulator Rac and promotes the activity of RhoA in this subcellular region. This Rac to RhoA switch promotes the extension of pseudopodial processes and invasive migration into FN-containing matrices, in a RhoA-dependent manner. Thus, the localized endocytic trafficking of α5β1 within the tips of invasive pseudopods elicits signals that promote the reorganization of the actin cytoskeleton, protrusion, and invasion into FN-rich ECM.

  9. Decreased Rac1 Cardiac Expression in Nitrofen-Induced Diaphragmatic Hernia.

    PubMed

    Nakamura, Hiroki; Zimmer, Julia; Puri, Prem

    2018-02-01

     The high incidence of cardiac malformations in humans and animal models with congenital diaphragmatic hernia (CDH) is well known. The hypoplasia of left heart is common among fetuses with CDH and has been identified as a poor prognostic factor. However, the precise mechanisms underlying cardiac maldevelopment in CDH are not fully understood. Ras-related C3 botulinum toxin substrate 1 (Rac1) plays a key role in cardiomyocyte polarity and embryonic heart development. Deficiency of Rac1 is reported to impair elongation and cytoskeletal organization of cardiomyocytes, resulting in congenital cardiac defects. We designed this study to test the hypothesis that Rac1 expression is downregulated in the developing hearts of rats with nitrofen-induced CDH.  Following ethical approval (REC1103), time-pregnant Sprague Dawley rats received nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on D18 and D21 and divided into CDH and control (CTRL) ( n  = 6 for each group and time point). Quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, and confocal-immunofluorescence microscopy were performed to detect cardiac gene and protein expression of Rac1.  qRT-PCR and Western blot analysis revealed that Rac1 expression was significantly decreased in the CDH group compared with controls ( p  < 0.05). Confocal-immunofluorescence microscopy revealed that Rac1 cardiac expression was markedly decreased in the CDH group compared with controls.  Decreased cardiac Rac1 expression in the nitrofen-induced CDH suggests that Rac1 deficiency during morphogenesis may impair structural cardiac remodeling, resulting in congenital cardiac defects. Georg Thieme Verlag KG Stuttgart · New York.

  10. 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

  11. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Rac1 Regulates Endometrial Secretory Function to Control Placental Development.

    PubMed

    Davila, Juanmahel; Laws, Mary J; Kannan, Athilakshmi; Li, Quanxi; Taylor, Robert N; Bagchi, Milan K; Bagchi, Indrani C

    2015-08-01

    During placenta development, a succession of complex molecular and cellular interactions between the maternal endometrium and the developing embryo ensures reproductive success. The precise mechanisms regulating this maternal-fetal crosstalk remain unknown. Our study revealed that the expression of Rac1, a member of the Rho family of GTPases, is markedly elevated in mouse decidua on days 7 and 8 of gestation. To investigate its function in the uterus, we created mice bearing a conditional deletion of the Rac1 gene in uterine stromal cells. Ablation of Rac1 did not affect the formation of the decidua but led to fetal loss in mid gestation accompanied by extensive hemorrhage. To gain insights into the molecular pathways affected by the loss of Rac1, we performed gene expression profiling which revealed that Rac1 signaling regulates the expression of Rab27b, another GTPase that plays a key role in targeting vesicular trafficking. Consequently, the Rac1-null decidual cells failed to secrete vascular endothelial growth factor A, which is a critical regulator of decidual angiogenesis, and insulin-like growth factor binding protein 4, which regulates the bioavailability of insulin-like growth factors that promote proliferation and differentiation of trophoblast cell lineages in the ectoplacental cone. The lack of secretion of these key factors by Rac1-null decidua gave rise to impaired angiogenesis and dysregulated proliferation of trophoblast cells, which in turn results in overexpansion of the trophoblast giant cell lineage and disorganized placenta development. Further experiments revealed that RAC1, the human ortholog of Rac1, regulates the secretory activity of human endometrial stromal cells during decidualization, supporting the concept that this signaling G protein plays a central and conserved role in controlling endometrial secretory function. This study provides unique insights into the molecular mechanisms regulating endometrial secretions that mediate stromal

  13. Rac1 GTPase regulates 11β hydroxysteroid dehydrogenase type 2 and fibrotic remodeling.

    PubMed

    Lavall, Daniel; Schuster, Pia; Jacobs, Nadine; Kazakov, Andrey; Böhm, Michael; Laufs, Ulrich

    2017-05-05

    The aim of the study was to characterize the role of Rac1 GTPase for the mineralocorticoid receptor (MR)-mediated pro-fibrotic remodeling. Transgenic mice with cardiac overexpression of constitutively active Rac1 (RacET) develop an age-dependent phenotype with atrial dilatation, fibrosis, and atrial fibrillation. Expression of MR was similar in RacET and WT mice. The expression of 11β hydroxysteroid dehydrogenase type 2 (11β-HSD2) was age-dependently up-regulated in the atria and the left ventricles of RacET mice on mRNA and protein levels. Statin treatment inhibiting Rac1 geranylgeranylation reduced 11β-HSD2 up-regulation. Samples of human left atrial myocardium showed a positive correlation between Rac1 activity and 11β-HSD2 expression ( r = 0.7169). Immunoprecipitation showed enhanced Rac1-bound 11β-HSD2 relative to Rac1 expression in RacET mice that was diminished with statin treatment. Both basal and phorbol 12-myristate 13-acetate (PMA)-induced NADPH oxidase activity were increased in RacET and correlated positively with 11β-HSD2 expression ( r = 0.788 and r = 0.843, respectively). In cultured H9c2 cardiomyocytes, Rac1 activation with l-buthionine sulfoximine increased; Rac1 inhibition with NSC23766 decreased 11β-HSD2 mRNA and protein expression. Connective tissue growth factor (CTGF) up-regulation induced by aldosterone was prevented with NSC23766. Cardiomyocyte transfection with 11β-HSD2 siRNA abolished the aldosterone-induced CTGF up-regulation. Aldosterone-stimulated MR nuclear translocation was blocked by the 11β-HSD2 inhibitor carbenoxolone. In cardiac fibroblasts, nuclear MR translocation induced by aldosterone was inhibited with NSC23766 and spironolactone. NSC23766 prevented the aldosterone-induced proliferation and migration of cardiac fibroblasts and the up-regulation of CTGF and fibronectin. In conclusion, Rac1 GTPase regulates 11β-HSD2 expression, MR activation, and MR-mediated pro-fibrotic signaling. © 2017 by The American Society for

  14. Stretch-stimulated glucose transport in skeletal muscle is regulated by Rac1

    PubMed Central

    Sylow, Lykke; Møller, Lisbeth L V; Kleinert, Maximilian; Richter, Erik A; Jensen, Thomas E

    2015-01-01

    An alternative to the canonical insulin signalling pathway for glucose transport is muscle contraction/exercise. Mechanical stress is an integrated part of the muscle contraction/relaxation cycle, and passive stretch stimulates muscle glucose transport. However, the signalling mechanism regulating stretch-stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1, was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction- and insulin-stimulated glucose transport, however, its role in stretch-stimulated glucose transport and signalling is unknown. We therefore investigated whether stretch-induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle-specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton in isolated soleus and extensor digitorum longus muscles. In addition, the role of Rac1 in contraction-stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which cross-bridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin. Knockout as well as pharmacological inhibition of Rac1 reduced stretch-stimulated glucose transport by 30–50% in soleus and extensor digitorum longus muscle. The actin depolymerizing agent latrunculin B similarly decreased glucose transport in response to stretching by 40–50%. Rac1 inhibition reduced contraction-stimulated glucose transport by 30–40% in tension developing muscle but did not affect contraction-stimulated glucose transport in muscles in which force development was prevented. Our findings suggest that Rac1 and the actin cytoskeleton regulate stretch-stimulated glucose transport and that Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. Key

  15. 48 CFR 750.7109 - Submission of requests by contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Submission of requests by contractors. 750.7109 Section 750.7109 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS Extraordinary Contractual Actions To Protect...

  16. 48 CFR 342.7002 - Procedures to be followed when a contractor fails to perform.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... when a contractor fails to perform. 342.7002 Section 342.7002 Federal Acquisition Regulations System... Procedures to be followed when a contractor fails to perform. (a) The Contracting Officer shall initiate immediate action to protect the Government's rights whenever the contractor fails to comply with either the...

  17. 48 CFR 342.7002 - Procedures to be followed when a contractor fails to perform.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... when a contractor fails to perform. 342.7002 Section 342.7002 Federal Acquisition Regulations System... Procedures to be followed when a contractor fails to perform. (a) The Contracting Officer shall initiate immediate action to protect the Government's rights whenever the contractor fails to comply with either the...

  18. 48 CFR 342.7002 - Procedures to be followed when a contractor fails to perform.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... when a contractor fails to perform. 342.7002 Section 342.7002 Federal Acquisition Regulations System... Procedures to be followed when a contractor fails to perform. (a) The Contracting Officer shall initiate immediate action to protect the Government's rights whenever the contractor fails to comply with either the...

  19. 48 CFR 342.7002 - Procedures to be followed when a contractor fails to perform.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... when a contractor fails to perform. 342.7002 Section 342.7002 Federal Acquisition Regulations System... Procedures to be followed when a contractor fails to perform. (a) The Contracting Officer shall initiate immediate action to protect the Government's rights whenever the contractor fails to comply with either the...

  20. 48 CFR 342.7002 - Procedures to be followed when a contractor fails to perform.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... when a contractor fails to perform. 342.7002 Section 342.7002 Federal Acquisition Regulations System... Procedures to be followed when a contractor fails to perform. (a) The Contracting Officer shall initiate immediate action to protect the Government's rights whenever the contractor fails to comply with either the...

  1. 78 FR 13547 - Defense Federal Acquisition Regulation Supplement: Alleged Crimes By or Against Contractor Personnel

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-28

    ... Contractor Personnel AGENCY: Defense Acquisition Regulations System, Department of Defense (DoD). ACTION... (FY) 2009 and expand coverage on contractor requirements and responsibilities relating to alleged crimes by or against contractor personnel. DATES: Effective February 28, 2013. FOR FURTHER INFORMATION...

  2. Contractor evaluations in the contractor selection process.

    DOT National Transportation Integrated Search

    2014-04-01

    The current contractor evaluation system in use within the Kentucky Transportation Cabinet is based on the contractor evaluation system developed as part of SPR 212-00 "Quality Based Prequalification of Contractors." This system relies on average per...

  3. 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

    ... of Language Services Contractor Application Form ACTION: Notice of request for public comment... Collection: Office of Language Services Contractor Application Form. OMB Control Number: 1405-0191. Type of... become contractors for the U.S. Department of State, Office of Language Services, the information...

  4. 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

    ... of Language Services Contractor Application Form ACTION: Notice of request for public comment and...: Title of Information Collection: Office of Language Services Contractor Application Form. OMB Control... States. If candidates successfully become contractors for the U.S. Department of State, Office of...

  5. RCP-driven α5β1 recycling suppresses Rac and promotes RhoA activity via the RacGAP1–IQGAP1 complex

    PubMed Central

    Jacquemet, Guillaume; Green, David M.; Bridgewater, Rebecca E.; von Kriegsheim, Alexander; Humphries, Martin J.; Norman, Jim C.

    2013-01-01

    Inhibition of αvβ3 or expression of mutant p53 promotes invasion into fibronectin (FN)-containing extracellular matrix (ECM) by enhancing Rab-coupling protein (RCP)–dependent recycling of α5β1 integrin. RCP and α5β1 cooperatively recruit receptor tyrosine kinases, including EGFR1, to regulate their trafficking and downstream signaling via protein kinase B (PKB)/Akt, which, in turn, promotes invasive migration. In this paper, we identify a novel PKB/Akt substrate, RacGAP1, which is phosphorylated as a consequence of RCP-dependent α5β1 trafficking. Phosphorylation of RacGAP1 promotes its recruitment to IQGAP1 at the tips of invasive pseudopods, and RacGAP1 then locally suppresses the activity of the cytoskeletal regulator Rac and promotes the activity of RhoA in this subcellular region. This Rac to RhoA switch promotes the extension of pseudopodial processes and invasive migration into FN-containing matrices, in a RhoA-dependent manner. Thus, the localized endocytic trafficking of α5β1 within the tips of invasive pseudopods elicits signals that promote the reorganization of the actin cytoskeleton, protrusion, and invasion into FN-rich ECM. PMID:24019536

  6. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Distinct Effects of Rac1 on Differentiation of Primary Avian Myoblasts

    PubMed Central

    Gallo, Rita; Serafini, Marco; Castellani, Loriana; Falcone, Germana; Alemà, Stefano

    1999-01-01

    Rho family GTPases have been implicated in the regulation of the actin cytoskeleton in response to extracellular cues and in the transduction of signals from the membrane to the nucleus. Their role in development and cell differentiation, however, is little understood. Here we show that the transient expression of constitutively active Rac1 and Cdc42 in unestablished avian myoblasts is sufficient to cause inhibition of myogenin expression and block of the transition to the myocyte compartment, whereas activated RhoA affects myogenic differentiation only marginally. Activation of c-Jun N-terminal kinase (JNK) appears not to be essential for block of differentiation because, although Rac1 and Cdc42 GTPases modestly activate JNK in quail myoblasts, a Rac1 mutant defective for JNK activation can still inhibit myogenic differentiation. Stable expression of active Rac1, attained by infection with a recombinant retrovirus, is permissive for terminal differentiation, but the resulting myotubes accumulate severely reduced levels of muscle-specific proteins. This inhibition is the consequence of posttranscriptional events and suggests the presence of a novel level of regulation of myogenesis. We also show that myotubes expressing constitutively active Rac1 fail to assemble ordered sarcomeres. Conversely, a dominant-negative Rac1 variant accelerates sarcomere maturation and inhibits v-Src–induced selective disassembly of I-Z-I complexes. Collectively, our findings provide a role for Rac1 during skeletal muscle differentiation and strongly suggest that Rac1 is required downstream of v-Src in the signaling pathways responsible for the dismantling of tissue-specific supramolecular structures. PMID:10512856

  8. Stretch-stimulated glucose transport in skeletal muscle is regulated by Rac1.

    PubMed

    Sylow, Lykke; Møller, Lisbeth L V; Kleinert, Maximilian; Richter, Erik A; Jensen, Thomas E

    2015-02-01

    Rac1 regulates stretch-stimulated (i.e. mechanical stress) glucose transport in muscle. Actin depolymerization decreases stretch-induced glucose transport in skeletal muscle. Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. An alternative to the canonical insulin signalling pathway for glucose transport is muscle contraction/exercise. Mechanical stress is an integrated part of the muscle contraction/relaxation cycle, and passive stretch stimulates muscle glucose transport. However, the signalling mechanism regulating stretch-stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1, was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction- and insulin-stimulated glucose transport, however, its role in stretch-stimulated glucose transport and signalling is unknown. We therefore investigated whether stretch-induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle-specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton in isolated soleus and extensor digitorum longus muscles. In addition, the role of Rac1 in contraction-stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which cross-bridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin. Knockout as well as pharmacological inhibition of Rac1 reduced stretch-stimulated glucose transport by 30-50% in soleus and extensor digitorum longus muscle. The actin depolymerizing agent latrunculin B similarly decreased glucose transport in response to stretching by 40-50%. Rac1 inhibition reduced contraction-stimulated glucose transport by 30-40% in tension developing muscle but did not affect contraction-stimulated glucose transport in

  9. Sanguinarine inhibits Rac1b-rendered cell survival enhancement by promoting apoptosis and blocking proliferation

    PubMed Central

    Ying, Li; Li, Gang; Wei, Si-si; Wang, Hong; An, Pei; Wang, Xun; Guo, Kai; Luo, Xian-jin; Gao, Ji-min; Zhou, Qing; Li, Wei; Yu, Ying; Li, Yi-gang; Duan, Jun-li; Wang, Yue-peng

    2015-01-01

    Aim: Small GTPase Rac1 is a member of the Ras superfamily, which plays important roles in regulation of cytoskeleton reorganization, cell growth, proliferation, migration, etc. The aim of this study was to determine how a constitutively active Rac1b regulated cell proliferation and to investigate the effects of the Rac1b inhibitor sanguinarine. Methods: Three HEK293T cell lines stably overexpressing GFP, Rac1-GFP or Rac1b-GFP were constructed by lentiviral infection. The cells were treated with sanguinarine (1 μmol/L) or its analogue berberine (1 μmol/L) for 4 d. Cell proliferation was evaluated by counting cell numbers and with a BrdU incorporation assay. The levels of cleaved PARP-89 (an apoptosis marker) and cyclin-D1 (a proliferative index) were measured using Western blotting. Results: In 10% serum-containing media, overexpressing either Rac1 or Rac1b did not significantly change the cell proliferation. In the serum-starved media, however, the survival rate of Rac1b cells was significantly increased, whereas that of Rac1 cells was moderately increased. The level of cleaved PARP-89 was significantly increased in serum-starved Rac1 cells, but markedly reduced in serum-starved Rac1b cells. The level of cyclin-D1 was significantly increased in both serum-starved Rac1 and Rac1b cells. Treatment with sanguinarine, but not berberine, inhibited the proliferation of Rac1b cells, which was accompanied by significantly increased the level of PARP-89, and decreased both the level of cyclin-D1 and the percentage of BrdU positive cells. Conclusion: Rac1b enhances the cell proliferation under a growth-limiting condition via both anti-apoptotic and pro-proliferative mechanisms. Sanguinarine, as the specific inhibitor of Rac1b, is a potential therapeutic agent for malignant tumors with up-regulated Rac1b. PMID:25544362

  10. 75 FR 78966 - Del Norte Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-17

    ... Washington Boulevard, Crescent City, California 95531. FOR FURTHER INFORMATION CONTACT: Adam Dellinger..., the public will present clarification on previously submitted Title II project proposals to the RAC. The RAC will vote on projects to recommend for funding. There will also be a public comment...

  11. 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

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Arulanandam, Rozanne; Geletu, Mulu; Feracci, Helene

    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 revealedmore » 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.« less

  13. 48 CFR 750.7109-2 - Form of requests by contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Form of requests by contractors. 750.7109-2 Section 750.7109-2 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS Extraordinary Contractual Actions To Protect...

  14. Altered focal adhesion regulation correlates with cardiomyopathy in mice expressing constitutively active rac1

    PubMed Central

    Sussman, Mark A.; Welch, Sara; Walker, Angela; Klevitsky, Raisa; Hewett, Timothy E.; Price, Robert L.; Schaefer, Erik; Yager, Karen

    2000-01-01

    The ras family of small GTP-binding proteins exerts powerful effects upon cell structure and function. One member of this family, rac, induces actin cytoskeletal reorganization in nonmuscle cells and hypertrophic changes in cultured cardiomyocytes. To examine the effect of rac1 activation upon cardiac structure and function, transgenic mice were created that express constitutively activated rac1 specifically in the myocardium. Transgenic rac1 protein was expressed at levels comparable to endogenous rac levels, with activation of the rac1 signaling pathway resulting in two distinct cardiomyopathic phenotypes: a lethal dilated phenotype associated with neonatal activation of the transgene and a transient cardiac hypertrophy seen among juvenile mice that resolved with age. Neither phenotype showed myofibril disarray and hypertrophic hearts were hypercontractilein working heart analyses. The rac1 target p21-activated kinase translocated from a cytosolic to a cytoskeletal distribution, suggesting that rac1 activation was inducing focal adhesion reorganization. Corroborating results showed altered localizations of src in dilated cardiomyopathy and paxillin in both cardiomyopathic phenotypes. This study, the first examination of rac1-mediated cardiac effects in vivo, demonstrates that dilation and hypertrophy can share a common molecular origin and presents evidence that both timing and concurrent signaling from multiple pathways can influence cardiac remodeling. PMID:10749567

  15. Rac1 GTPase activates the WAVE regulatory complex through two distinct binding sites.

    PubMed

    Chen, Baoyu; Chou, Hui-Ting; Brautigam, Chad A; Xing, Wenmin; Yang, Sheng; Henry, Lisa; Doolittle, Lynda K; Walz, Thomas; Rosen, Michael K

    2017-09-26

    The Rho GTPase Rac1 activates the WAVE regulatory complex (WRC) to drive Arp2/3 complex-mediated actin polymerization, which underpins diverse cellular processes. Here we report the structure of a WRC-Rac1 complex determined by cryo-electron microscopy. Surprisingly, Rac1 is not located at the binding site on the Sra1 subunit of the WRC previously identified by mutagenesis and biochemical data. Rather, it binds to a distinct, conserved site on the opposite end of Sra1. Biophysical and biochemical data on WRC mutants confirm that Rac1 binds to both sites, with the newly identified site having higher affinity and both sites required for WRC activation. Our data reveal that the WRC is activated by simultaneous engagement of two Rac1 molecules, suggesting a mechanism by which cells may sense the density of active Rac1 at membranes to precisely control actin assembly.

  16. Ibuprofen Inhibits Colitis-Induced Overexpression of Tumor-Related Rac1b1

    PubMed Central

    Matos, Paulo; Kotelevets, Larissa; Goncalves, Vania; Henriques, Andreia; Zerbib, Philippe; Moyer, Mary Pat; Chastre, Eric; Jordan, Peter

    2013-01-01

    The serrated pathway to colorectal tumor formation involves oncogenic mutations in the BRAF gene, which are sufficient for initiation of hyperplastic growth but not for tumor progression. A previous analysis of colorectal tumors revealed that overexpression of splice variant Rac1b occurs in around 80% of tumors with mutant BRAF and both events proved to cooperate in tumor cell survival. Here, we provide evidence for increased expression of Rac1b in patients with inflamed human colonic mucosa as well as following experimentally induced colitis in mice. The increase of Rac1b in the mouse model was specifically prevented by the nonsteroidal anti-inflammatory drug ibuprofen, which also inhibited Rac1b expression in cultured HT29 colorectal tumor cells through a cyclooxygenase inhibition.independent mechanism. Accordingly, the presence of ibuprofen led to a reduction of HT29 cell survival in vitro and inhibited Rac1b-dependent tumor growth of HT29 xenografts. Together, our results suggest that stromal cues, namely, inflammation, can trigger changes in Rac1b expression in the colon and identify ibuprofen as a highly specific and efficient inhibitor of Rac1b overexpression in colorectal tumors. Our data suggest that the use of ibuprofen may be beneficial in the treatment of patients with serrated colorectal tumors or with inflammatory colon syndromes. PMID:23359345

  17. Rac2 deficiency attenuates CCl4-induced liver injury through suppressing inflammation and oxidative stress.

    PubMed

    Zou, Yan; Xiong, Ji-Bin; Ma, Ke; Wang, Ai-Zhong; Qian, Ke-Jian

    2017-10-01

    Oxidative stress is a leading cause to liver injury. Rac2 is a Ras-associated guanosine triphosphatase, an important molecule modulating a large number of cells and involved in the regulation of reactive oxygen species (ROS). For the study described here, we supposed that Rac2 knockout protects mice against CCl 4 -induced acute liver injury. We found that Rac2 expressed highly in CCl 4 -induced liver tissues. CCl 4 -treated Rac2 knockout (Rac2-/-) mice had reduced CD24 levels and steatosis. In addition, CCl 4 -induced high expression of pro-inflammatory cytokines and chemokine were reversed by Rac2 deficiency compared to CCl 4 -treated wild type (WT) mice. We also found that fibrosis-related signals of MMP-9, MMP-2 and TGF-β1 were also down-regulated in Rac2 knockout mice induced by CCl 4 . Significantly, oxidative stress induced by CCl 4 was also suppressed owing to the lack of Rac2, evidenced by enhanced superoxide dismutase (SOD) activity, and reduced malondialdehyde (MDA) levels, superoxide radical, H 2 O 2 , xanthine oxidase (XO), xanthine dehydrogenase (XDH) and XO/XDH ratio. Moreover, c-Jun N-terminal protein kinase mitogen-activated protein kinases (JNK MAPK) was activated by CCl 4 , which was reversed in the liver of Rac2-/- mice through western blot and immunohistochemical analysis. In vitro, endotoxin (LPS) was treated to hepatocytes isolated from WT mice and Rac2-/- mice. The data further confirmed the role of Rac2 deficiency suppressed pro-inflammatory cytokines and chemokine, as well as fibrosis-related signals. Of note, production of ROS induced by LPS was reduced in Rac2-/- cells, accompanied with enhanced SOD1, SOD2 and reduced XO and phosphorylated-JNK expressions. Our results indicated that Rac2 played an essential role in acute liver injury induced by CCl 4 , providing the compelling information of the effects of Rac2 on liver injury, and revealing a novel regulatory mechanism for acute liver injury. Copyright © 2017. Published by Elsevier

  18. Rac2 Functions in Both Neutrophils and Macrophages To Mediate Motility and Host Defense in Larval Zebrafish.

    PubMed

    Rosowski, Emily E; Deng, Qing; Keller, Nancy P; Huttenlocher, Anna

    2016-12-15

    Leukocyte motility is required for host defense responses. Rac-family Rho GTPases are implicated in leukocyte function; however, the distinct roles of different Rac isoforms in host defense in vivo have remained unclear. In this study, we generated Rac2-deficient zebrafish using transcription activator-like effector nucleases to directly compare the role of Rac2 in vivo in neutrophils and macrophages in motility and the response to infection. This zebrafish larval model is highly amenable to live imaging of leukocyte behavior, and we report that in rac2 -/- larvae both neutrophils and macrophages are defective in basic motility, leading to impaired responses to localized wounds or infections. rac2 -/- larvae are highly susceptible to infection with Pseudomonas aeruginosa, which can be almost fully rescued by ectopic expression of either Rac2 or Rac1 specifically in neutrophils, indicating that these isoforms have partially overlapping functions in vivo. Rescue of Rac2 expression specifically in macrophages also confers resistance to Pseudomonas infection, highlighting an important role for Rac2 in this leukocyte population as well. Surprisingly, in contrast to neutrophils expressing a Rac2 dominant inhibitory human disease mutation, rac2 -/- neutrophils do not have altered polarity or mobilization from hematopoietic tissue, suggesting that a different Rac isoform, such as Rac1, also contributes to these phenotypes in vivo. Copyright © 2016 by The American Association of Immunologists, Inc.

  19. Deacetylmycoepoxydiene is an agonist of Rac1, and simultaneously induces autophagy and apoptosis.

    PubMed

    Xie, Wei; Zhang, Wei; Sun, Mingwei; Lu, Chunhua; Shen, Yuemao

    2018-05-09

    Lung cancer is the second most common cause of cancer-related death in the world. Most cases of lung cancer are not curable, especially non-small cell lung cancer (NSCLC). Thus, novel treatment targets for this malignant disease are urgently needed. Here, we demonstrate the feasibility of Rac1 in treating p53-null human NSCLC H1299 as a novel drug target. Deacetylmycoepoxydiene (DA-MED), a cytotoxic natural polyketide, functions as a Rac1 agonist in p53-null NSCLC H1299 cells. DA-MED treatment drives Rac1 activation and promotes robust production of reactive oxygen species, activating mitochondrial permeability transition and the intrinsic apoptotic pathway. Knockdown of Rac1 decreases ROS production in DA-MED-treated cells, resulting in a concomitant decrease in DA-MED-induced apoptosis. DA-MED-activated Rac1 induces autophagy by inhibiting mammalian target of rapamycin, leading to anti-apoptotic and anti-metastatic effects. Therefore, this study provides novel insight into the complex cytotoxic and pro-survival mechanisms associated with a potent Rac1 agonist and suggests that further development of more potent Rac1 agonists could be an effective strategy for future non-small cell lung cancer treatments.

  20. 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

  1. WAVE2 serves a functional partner of IRSp53 by regulating its interaction with Rac.

    PubMed

    Miki, Hiroaki; Takenawa, Tadaomi

    2002-04-26

    We previously reported that IRSp53 binds both Rac and WAVE2, inducing formation of Rac/IRSp53/WAVE2 complex that is important for membrane ruffling. However, recent reports noted a specific interaction between IRSp53 and Cdc42 but not Rac, which led us to re-examine the binding of IRSp53 to Rac. Immunoprecipitation analysis and pull-down assay reveal that full-length IRSp53 binds Rac much less efficiently than the N-terminal fragment, which may be caused by intramolecular interaction. Interestingly, the intramolecular interaction is interrupted by the binding of WAVE2 and full-length IRSp53 associates with Rac in the presence of WAVE2. We also report that IRSp53 induces spreading and neurite formation of N1E-115 cells, which presumably reflect functional cooperation with Rac.

  2. Expression of Ras-related C3 botulinum toxin substrate 1 (RAC1) in human cholesteatoma.

    PubMed

    Lee, No Hee; Chang, Ji-Won; Choi, June; Jung, Hak Hyun; Im, Gi Jung

    2013-02-01

    Ras-related C3 botulinum toxin substrate 1 (RAC1) is a 21-kDa signaling G protein that functions as a pleiotropic regulator of many cellular processes including epithelial differentiation. RAC1 activates the nicotinamide adenine dinucleotide phosphate oxidase complex which promotes formation of reactive oxygen species and degradation enzymes. RAC1 has been associated with rapid epithelial differentiation and invasive properties in human cholesteatoma. This study aimed to identify the presence of RAC1 in human cholesteatoma and analyze its functional role as a regulator of proteolysis and overgrowth. Tissue samples from human cholesteatoma and normal postaural skin were obtained from patients during otologic surgery for cholesteatoma. The expression of RAC1 mRNA was quantified by real-time RT-PCR, and localization of RAC1 expression was confirmed using immunohistochemical staining. Expression of RAC1 mRNA in the epithelium of cholesteatoma was significantly elevated 2.94 fold on average, compared with normal control skin. RAC1 expression in the suprabasal and basal layer of cholesteatoma epithelium was stronger than normal control skin. Our results suggest that RAC1 can be associated with rapid epithelial differentiation and invasive properties of human cholesteatoma.

  3. 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

  4. Rac3 Regulates Cell Invasion, Migration and EMT in Lung Adenocarcinoma through p38 MAPK Pathway

    PubMed Central

    Zhang, Chenlei; Liu, Tieqin; Wang, Gebang; Wang, Huan; Che, Xiaofang; Gao, Xinghua; Liu, Hongxu

    2017-01-01

    Background: The role of Rac3 in cell proliferation in lung adenocarcinoma has been tackled in our previous study. However, the role of Rac3 in cell invasion and migration of lung adenocarcinoma is still not clear. Methods: The expression of Rac3 in lung adenocarcinoma specimens and paired noncancerous normal tissues were evaluated by immunohistochemistry. Lentivirus-mediated RNA interference (RNAi) was employed to silence Rac3 in lung adenocarcinoma cell lines A549 and H1299. A p38 MAPK inhibitor (LY2228820) was employed to inhibit activity of p38 MAPK pathway. Cell invasion and migration in vitro were examined by invasion and migration assays, respectively. PathScan® intracellular signaling array kit and western blot were employed in mechanism investigation. Results: Rac3 expression was frequently higher in lung adenocarcinoma than paired noncancerous normal tissues. Rac3 expression was an independent risk factor for lymphonode metastasis, and was associated with worse survival outcome. Silencing of Rac3 inhibited cell invasion and cell migration in lung adenocarcinoma cell lines. Knockdown of Rac3 decreased activity of p38 MAPK pathway. LY2228820, which was an important p38 MAPK inhibitor, inhibited Rac3-induced cell invasion and migration of lung adenocarcinoma. E-cadherin expression was increased and vimentin expression was decreased after silencing of Rac3 or following the treatment of LY2228820. Conclusions: Our findings suggest that Rac3 regulates cell invasion, migration and EMT via p38 MAPK pathway. Rac3 may be a potential biomarker of invasion and metastasis for lung adenocarcinoma, and knockdown of Rac3 may potentially serve as a promising therapeutic target for lung adenocarcinoma. PMID:28900489

  5. Intracellular mature IL-37 suppresses tumor metastasis via inhibiting Rac1 activation.

    PubMed

    Li, Y; Zhao, M; Guo, C; Chu, H; Li, W; Chen, X; Wang, X; Li, Y; Jia, Y; Koussatidjoa, S; Zhu, F; Wang, J; Wang, X; Wang, Q; Zhao, W; Shi, Y; Chen, W; Zhang, L

    2018-02-22

    IL-37, a newly found anti-inflammatory cytokine of the IL-1 family, has both extracellular and intracellular functions. Accumulating evidences indicate that it is also involved in tumor progression. However, the mechanism and its intracellular target are unclear. In this study, clinical data from 84 patients showed that loss or reduced expression of IL-37 in lung adenocarcinoma tissues was significantly associated with tumor metastasis. We further provided evidence that IL-37 inhibited effectively tumor metastasis in vitro and in vivo. Moreover, we uncovered a novel mechanism by which IL-37 suppressed tumor cell migration via its intracellular mature form (amino acids 46-218). Intracellular mature form of IL-37, but not its extracellular form, markedly inhibited migration of multiple kinds of tumor cells through inhibiting Rac1 activation. Mechanistically, intracellular mature IL-37 directly bound to the CAAX motif in the C-terminal hypervariable region of Rac1, and then inhibited Rac1 membrane translocation and subsequent downstream signaling. Our research identifies intracellular mature IL-37 as a novel endogenous inhibitor of Rac1. Given the crucial roles of Rac1 in tumor angiogenesis and metastasis, intracellular mature IL-37 might serve as a potential strategy for the control of Rac1 activity and tumor progression.

  6. Cigarette smoke-induced alveolar epithelial-mesenchymal transition is mediated by Rac1 activation.

    PubMed

    Shen, Hui-juan; Sun, Yan-hong; Zhang, Shui-juan; Jiang, Jun-xia; Dong, Xin-wei; Jia, Yong-liang; Shen, Jian; Guan, Yan; Zhang, Lin-hui; Li, Fen-fen; Lin, Xi-xi; Wu, Xi-mei; Xie, Qiang-min; Yan, Xiao-feng

    2014-06-01

    Epithelial-mesenchymal transition (EMT) is the major pathophysiological process in lung fibrosis observed in chronic obstructive pulmonary disease (COPD) and lung cancer. Smoking is a risk factor for developing EMT, yet the mechanism remains largely unknown. In this study, we investigated the role of Rac1 in cigarette smoke (CS) induced EMT. EMT was induced in mice and pulmonary epithelial cells by exposure of CS and cigarette smoke extract (CSE) respectively. Treatment of pulmonary epithelial cells with CSE elevated Rac1 expression associated with increased TGF-β1 release. Blocking TGF-β pathway restrained CSE-induced changes in EMT-related markers. Pharmacological inhibition or knockdown of Rac1 decreased the CSE exposure induced TGF-β1 release and ameliorated CSE-induced EMT. In CS-exposed mice, pharmacological inhibition of Rac1 reduced TGF-β1 release and prevented aberrations in expression of EMT markers, suggesting that Rac1 is a critical signaling molecule for induction of CS-stimulated EMT. Furthermore, Rac1 inhibition or knockdown abrogated CSE-induced Smad2 and Akt (PKB, protein kinase B) activation in pulmonary epithelial cells. Inhibition of Smad2, PI3K (phosphatidylinositol 3-kinase) or Akt suppressed CSE-induced changes in epithelial and mesenchymal marker expression. Altogether, these data suggest that CS initiates EMT through Rac1/Smad2 and Rac1/PI3K/Akt signaling pathway. Our data provide new insights into the fundamental basis of EMT and suggest a possible new course of therapy for COPD and lung cancer. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Jiying; Rao, Qing, E-mail: raoqing@gmail.com; Wang, Min

    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,more » 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.« less

  8. Inhibition of Rac1 Activity in the Hippocampus Impairs the Forgetting of Contextual Fear Memory.

    PubMed

    Jiang, Lizhu; Mao, Rongrong; Zhou, Qixin; Yang, Yuexiong; Cao, Jun; Ding, Yuqiang; Yang, Yuan; Zhang, Xia; Li, Lingjiang; Xu, Lin

    2016-03-01

    Fear is crucial for survival, whereas hypermnesia of fear can be detrimental. Inhibition of the Rac GTPase is recently reported to impair the forgetting of initially acquired memory in Drosophila. Here, we investigated whether inhibition of Rac1 activity in rat hippocampus could contribute to the hypermnesia of contextual fear. We found that spaced but not massed training of contextual fear conditioning caused inhibition of Rac1 activity in the hippocampus and heightened contextual fear. Furthermore, intrahippocampal injection of the Rac1 inhibitor NSC23766 heightened contextual fear in massed training, while Rac1 activator CN04-A weakened contextual fear in spaced training rats. Our study firstly demonstrates that contextual fear memory in rats is actively regulated by Rac1 activity in the hippocampus, which suggests that the forgetting impairment of traumatic events in posttraumatic stress disorder may be contributed to the pathological inhibition of Rac1 activity in the hippocampus.

  9. 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. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2016-08-23

    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-Rac(CA)) revealed fewer but larger ESVs than control cells. Consistent with the phenotype of premature maturation of ESVs in HA-Rac(CA)-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. The encystation process is crucial for the transmission of giardiasis and the life cycle of many protists. Encystation for Giardia lamblia involves the assembly of a protective cyst wall

  11. 76 FR 17106 - Secure Rural Schools Resource Advisory Committee (RAC) Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-28

    ... DEPARTMENT OF AGRICULTURE Forest Service Secure Rural Schools Resource Advisory Committee (RAC... meeting to be held authorized under the Secure Rural Schools Act and Community Self-Determination Act... federally designated Secure Rural Schools Resource Advisory Committee (RAC). The public is invited to attend...

  12. Rac1 mediates laminar shear stress-induced vascular endothelial cell migration

    PubMed Central

    Huang, Xianliang; Shen, Yang; Zhang, Yi; Wei, Lin; Lai, Yi; Wu, Jiang; Liu, Xiaojing; Liu, Xiaoheng

    2013-01-01

    The migration of endothelial cells (ECs) plays an important role in vascular remodeling and regeneration. ECs are constantly subjected to shear stress resulting from blood flow and are able to convert mechanical stimuli into intracellular signals that affect cellular behaviors and functions. The aim of this study is to elucidate the effects of Rac1, which is the member of small G protein family, on EC migration under different laminar shear stress (5.56, 10.02, and 15.27 dyn/cm2). The cell migration distance under laminar shear stress increased significantly than that under the static culture condition. Especially, under relative high shear stress (15.27 dyn/cm2) there was a higher difference at 8 h (P < 0.01) and 2 h (P < 0.05) compared with static controls. RT-PCR results further showed increasing mRNA expression of Rac1 in ECs exposed to laminar shear stress than that exposed to static culture. Using plasmids encoding the wild-type (WT), an activated mutant (Q61L), and a dominant-negative mutant (T17N), plasmids encoding Rac1 were transfected into EA.hy 926 cells. The average net migration distance of Rac1Q61L group increased significantly, while Rac1T17N group decreased significantly in comparison with the static controls. These results indicated that Rac1 mediated shear stress-induced EC migration. Our findings conduce to elucidate the molecular mechanisms of EC migration induced by shear stress, which is expected to understand the pathophysiological basis of wound healing in health and diseases. PMID:24430179

  13. 48 CFR 970.5203-3 - Contractor's organization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Officer a chart showing the names, duties, and organization of key personnel (see 48 CFR 952.215-70) to be... employee competency, conduct, and integrity and shall be responsible for taking such disciplinary action... work under the contract. This includes the right to direct the Contractor to remove its most senior key...

  14. 48 CFR 970.5203-3 - Contractor's organization.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Officer a chart showing the names, duties, and organization of key personnel (see 48 CFR 952.215-70) to be... employee competency, conduct, and integrity and shall be responsible for taking such disciplinary action... work under the contract. This includes the right to direct the Contractor to remove its most senior key...

  15. 48 CFR 970.5203-3 - Contractor's organization.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Officer a chart showing the names, duties, and organization of key personnel (see 48 CFR 952.215-70) to be... employee competency, conduct, and integrity and shall be responsible for taking such disciplinary action... work under the contract. This includes the right to direct the Contractor to remove its most senior key...

  16. 48 CFR 970.5203-3 - Contractor's organization.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Officer a chart showing the names, duties, and organization of key personnel (see 48 CFR 952.215-70) to be... employee competency, conduct, and integrity and shall be responsible for taking such disciplinary action... work under the contract. This includes the right to direct the Contractor to remove its most senior key...

  17. Small G protein Rac GTPases regulate the maintenance of glioblastoma stem-like cells in vitro and in vivo.

    PubMed

    Lai, Yun-Ju; Tsai, Jui-Cheng; Tseng, Ying-Ting; Wu, Meng-Shih; Liu, Wen-Shan; Lam, Hoi-Ian; Yu, Jei-Hwa; Nozell, Susan E; Benveniste, Etty N

    2017-03-14

    Glioblastoma is the most common and aggressive malignant brain tumor in adults. The existence of glioblastoma stem cells (GSCs) or stem-like cells (stemloids) may account for its invasiveness and high recurrence. Rac proteins belong to the Rho small GTPase subfamily which regulates cell movement, proliferation, and survival. To investigate whether Rac proteins can serve as therapeutic targets for glioblastoma, especially for GSCs or stemloids, we examined the potential roles of Rac1, Rac2 and Rac3 on the properties of tumorspheres derived from glioblastoma cell lines. Tumorspheres are thought to be glioblastoma stem-like cells. We showed that Rac proteins promote the STAT3 and ERK activation and enhance cell proliferation and colony formation of glioblastoma stem-like cells. Knockdown of Rac proteins reduces the expression of GSC markers, such as CD133 and Sox2. The in vivo effects of Rac proteins in glioblastoma were further studied in zebrafish and in the mouse xenotransplantation model. Knocking-down Rac proteins abolished the angiogenesis effect induced by the injected tumorspheres in zebrafish model. In the CD133+-U373-tumorsphere xenotransplanted mouse model, suppression of Rac proteins decreased the incidence of tumor formation and inhibited the tumor growth. Moreover, knockdown of Rac proteins reduced the sphere forming efficiency of cells derived from these tumors. In conclusion, not only Rac1 but also Rac2 and 3 are important for glioblastoma tumorigenesis and can serve as the potential therapeutic targets against glioblastoma and its stem-like cells.

  18. Small G protein Rac GTPases regulate the maintenance of glioblastoma stem-like cells in vitro and in vivo

    PubMed Central

    Lai, Yun-Ju; Tsai, Jui-Cheng; Tseng, Ying-Ting; Wu, Meng-Shih; Liu, Wen-Shan; Lam, Hoi-Ian; Yu, Jei-Hwa; Nozell, Susan E.; Benveniste, Etty N.

    2017-01-01

    Glioblastoma is the most common and aggressive malignant brain tumor in adults. The existence of glioblastoma stem cells (GSCs) or stem–like cells (stemloids) may account for its invasiveness and high recurrence. Rac proteins belong to the Rho small GTPase subfamily which regulates cell movement, proliferation, and survival. To investigate whether Rac proteins can serve as therapeutic targets for glioblastoma, especially for GSCs or stemloids, we examined the potential roles of Rac1, Rac2 and Rac3 on the properties of tumorspheres derived from glioblastoma cell lines. Tumorspheres are thought to be glioblastoma stem-like cells. We showed that Rac proteins promote the STAT3 and ERK activation and enhance cell proliferation and colony formation of glioblastoma stem-like cells. Knockdown of Rac proteins reduces the expression of GSC markers, such as CD133 and Sox2. The in vivo effects of Rac proteins in glioblastoma were further studied in zebrafish and in the mouse xenotransplantation model. Knocking-down Rac proteins abolished the angiogenesis effect induced by the injected tumorspheres in zebrafish model. In the CD133+-U373-tumorsphere xenotransplanted mouse model, suppression of Rac proteins decreased the incidence of tumor formation and inhibited the tumor growth. Moreover, knockdown of Rac proteins reduced the sphere forming efficiency of cells derived from these tumors. In conclusion, not only Rac1 but also Rac2 and 3 are important for glioblastoma tumorigenesis and can serve as the potential therapeutic targets against glioblastoma and its stem-like cells. PMID:28160553

  19. Rac1 as a potential therapeutic target for chemo-radioresistant head and neck squamous cell carcinomas (HNSCC).

    PubMed

    Skvortsov, S; Dudás, J; Eichberger, P; Witsch-Baumgartner, M; Loeffler-Ragg, J; Pritz, C; Schartinger, V H; Maier, H; Hall, J; Debbage, P; Riechelmann, H; Lukas, P; Skvortsova, I

    2014-05-27

    In order to improve therapy for HNSCC patients, novel methods to predict and combat local and/or distant tumour relapses are urgently needed. This study has been dedicated to the hypothesis that Rac1, a Rho GTPase, is implicated in HNSCC insensitivity to chemo-radiotherapy resulting in tumour recurrence development. Parental and radiation-resistant (IRR) HNSCC cells were used to support this hypothesis. All cells were investigated for their sensitivity to ionising radiation and cisplatin, Rac1 activity, its intracellular expression and subcellular localisation. Additionally, tumour tissues obtained from 60 HNSCC patients showing different therapy response were evaluated for intratumoral Rac1 expression. Radiation-resistant IRR cells also revealed resistance to cisplatin accompanied by increased expression, activity and trend towards nuclear translocation of Rac1 protein. Chemical inhibition of Rac1 expression and activity resulted in significant improvement of HNSCC sensitivity to ionising radiation and cisplatin. Preclinical results were confirmed in clinical samples. Although Rac1 was poorly presented in normal mucosa, tumour tissues revealed increased Rac1 expression. The most pronounced Rac1 presence was observed in HNSCC patients with poor early or late responses to chemo-radiotherapy. Tissues taken at recurrence were characterised not only by enhanced Rac1 expression but also increased nuclear Rac1 content. Increased expression, activity and subcellular localisation of Rac1 could be associated with lower early response rate and higher risk of tumour recurrences in HNSCC patients and warrants further validation in larger independent studies. Inhibition of Rac1 activity can be useful in overcoming treatment resistance and could be proposed for HNSCC patients with primary or secondary chemo-radioresistance.

  20. Adenylyl cyclase localization to the uropod of aggregating Dictyostelium cells requires RacC

    PubMed Central

    Wang, C.; Jung, D.; Cao, Z.; Chung, C. Y.

    2015-01-01

    The localization of adenylyl cyclase A (ACA) to uropod of cells is required for the stream formation during Dictyostelium development. RacC is a Dictyostelium orthologue of Cdc42. We identified a streaming defect of racC− cells as they are clearly less polarized and form smaller and fragmented streams. ACA-YFP is mainly associated with intracellular vesicular structures, but not with the plasma membrane in racC− cells. racC− cells have a slightly higher number of vesicles than Ax3 cells, suggesting that the defect of ACA trafficking is not simply due to the lack of vesicle formation. While the ACA-YFP vesicles traveled with an average velocity of 9.1 µm/min in Ax3 cells, a slow and diffusional movement without direction with an average velocity of 4 µm/min was maintained in racC− cells. Images acquired by using total internal reflection fluorescence (TIRF) microscopy and fluorescence recovery after photobleaching (FRAP) analysis revealed that a significantly decreased number of ACA-YFP vesicles appeared near the cell membrane, indicating a defect in ACA-YFP vesicle trafficking. These results suggest an important role of RacC in the rapid and directional movements of ACA vesicles on microtubules to the plasma membrane, especially to the back of polarized cell. PMID:26315268

  1. The Rac-GAP alpha2-chimaerin regulates hippocampal dendrite and spine morphogenesis.

    PubMed

    Valdez, Chris M; Murphy, Geoffrey G; Beg, Asim A

    2016-09-01

    Dendritic spines are fine neuronal processes where spatially restricted input can induce activity-dependent changes in one spine, while leaving neighboring spines unmodified. Morphological spine plasticity is critical for synaptic transmission and is thought to underlie processes like learning and memory. Significantly, defects in dendritic spine stability and morphology are common pathogenic features found in several neurodevelopmental and neuropsychiatric disorders. The remodeling of spines relies on proteins that modulate the underlying cytoskeleton, which is primarily composed of filamentous (F)-actin. The Rho-GTPase Rac1 is a major regulator of F-actin and is essential for the development and plasticity of dendrites and spines. However, the key molecules and mechanisms that regulate Rac1-dependent pathways at spines and synapses are not well understood. We have identified the Rac1-GTPase activating protein, α2-chimaerin, as a critical negative regulator of Rac1 in hippocampal neurons. The loss of α2-chimaerin significantly increases the levels of active Rac1 and induces the formation of aberrant polymorphic dendritic spines. Further, disruption of α2-chimaerin signaling simplifies dendritic arbor complexity and increases the presence of dendritic spines that appear poly-innervated. Our data suggests that α2-chimaerin serves as a "brake" to constrain Rac1-dependent signaling to ensure that the mature morphology of spines is maintained in response to network activity. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. 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.

  3. Impact of point mutation P29S in RAC1 on tumorigenesis.

    PubMed

    Rajendran, Vidya; Gopalakrishnan, Chandrasekhar; Purohit, Rituraj

    2016-11-01

    A point mutation (P29S) in the RAS-related C3 botulinum toxin substrate 1 (RAC1) was considered to be a trigger for melanoma, a form of skin cancer with highest mortality rate. In this study, we have investigated the pathogenic role of P29S based on the conformational behavior of RAC1 protein toward guanosine triphosphate (GTP). Molecular interaction, molecular dynamics trajectory analysis (RMSD, RMSF, Rg, SASA, DSSP, and PCA), and shape analysis of binding pocket were performed to analyze the interaction energy and the dynamic behavior of native and mutant RAC1 at the atomic level. Due to this mutation, the RAC1 switch I region acquired more flexibility and, to compensate it, the switch II region becomes rigid in their conformational space, as a result of which the interaction energy of the protein for GTP increased. The overall results strongly implied that the changes in atomic conformation of the switch I and II regions in mutant RAC1 protein were a significant reason for its malignant transformation and tumorigenesis. We raised the opportunity for researchers to design possible therapeutic molecule by considering our findings.

  4. Bretylium potentiation of the contractor responses of isolated rabbit aortic strips to potassium and tyramine.

    PubMed

    Kurahashi, K; Shibata, S

    1971-09-01

    1. Pretreatment of rabbit aortic strips with bretylium potentiated the contractor response to potassium and tyramine but not to noradrenaline. On the other hand, such pretreatment inhibited the response to nicotine.2. Even in reserpinized or cold stored aortic strips, pretreatment with bretylium enhanced the contractor response to potassium and tyramine.3. Pretreatment of fresh, reserpinized, or cold stored aortic strips with pheniprazine potentiated the contractor response to potassium and tyramine.4. Pretreatment of aortic strips with bretylium or pheniprazine did not potentiate the response to 5-hydroxytryptamine (5-HT).5. The results indicate that both bretylium and pheniprazine potentiate the action of tyramine and potassium, not by presynaptic mechanisms, but by postsynaptic action, causing an increase in the sensitivity of the effector cells to the stimulants.

  5. Divergent functions of the Rho GTPases Rac1 and Cdc42 in podocyte injury

    PubMed Central

    Blattner, Simone M.; Hodgin, Jeffrey B.; Nishio, Masashi; Wylie, Stephanie; Saha, Jharna; Soofi, Abdul; Vining, Courtenay; Randolph, Ann; Herbach, Nadja; Wanke, Ruediger; Atkins, Kevin B.; Kang, Hee Gyung; Henger, Anna; Brakebusch, Cord; Holzman, Lawrence B.; Kretzler, Matthias

    2013-01-01

    Podocytes are highly specialized epithelial cells with complex actin cytoskeletal architecture crucial for maintenance of the glomerular filtration barrier. The mammalian Rho GTPases Rac1 and Cdc42 are molecular switches that control many cellular processes, but are best known for their roles in the regulation of actin cytoskeleton dynamics. Here we employed podocyte-specific Cre-lox technology and found that mice with deletion of Rac1 display normal podocyte morphology without glomerular dysfunction well into adulthood. Using the protamine sulfate model of acute podocyte injury, podocyte-specific deletion of Rac1 prevented foot process effacement. In a long-term model of chronic hypertensive glomerular damage, however, loss of Rac1 led to an exacerbation of albuminuria and glomerulosclerosis. In contrast, mice with podocyte-specific deletion of Cdc42 had severe proteinuria, podocyte foot process effacement, and glomerulosclerosis beginning as early as 10 days of age. In addition, slit diaphragm proteins nephrin and podocin were redistributed and cofilin was de-phosphorylated. Cdc42 is necessary for the maintenance of podocyte structure and function, but Rac1 is entirely dispensable in physiologic steady state. However, Rac1 has either beneficial or deleterious effects depending on the context of podocyte impairment. Thus, our study highlights the divergent roles of Rac1 and Cdc42 function in podocyte maintenance and injury. PMID:23677246

  6. RotundRacGAP Functions with Ras during Spermatogenesis and Retinal Differentiation in Drosophila melanogaster

    PubMed Central

    Bergeret, Evelyne; Pignot-Paintrand, Isabelle; Guichard, Annabel; Raymond, Karine; Fauvarque, Marie-Odile; Cazemajor, Michel; Griffin-Shea, Ruth

    2001-01-01

    Our analysis of rotund (rn) null mutations in Drosophila melanogaster revealed that deletion of the rn locus affects both spermatid and retinal differentiation. In the male reproductive system, the absence of RnRacGAP induced small testes, empty seminal vesicles, short testicular cysts, reduced amounts of interspermatid membrane, the absence of individualization complexes, and incomplete mitochondrial condensation. Flagellar growth continued within the short rn null cysts to produce large bulbous terminations of intertwined mature flagella. Organization of the retina was also severely perturbed as evidenced by grossly misshapen ommatidia containing reduced numbers of photoreceptor and pigment cells. These morphological phenotypes were rescued by genomic rnRacGAP transgenes, demonstrating that RnRacGAP function is critical to spermatid and retinal differentiation. The testicular phenotypes were suppressed by heterozygous hypomorphic mutations in the Dras1 and drk genes, indicating cross talk between RacGAP-regulated signaling and that of the Ras pathway. The observed genetic interactions are consistent with a model in which Rac signaling is activated by Ras and negatively regulated by RnRacGAP during spermatid differentiation. RnRacGAP and Ras cross talk also operated during retinal differentiation; however, while the heterozygous hypomorphic drk mutation continued to act as a suppressor of the rn null mutation, the heterozygous hypomorphic Dras1 mutation induced novel retinal phenotypes. PMID:11509670

  7. A Rac Homolog Is Required for Induction of Hyphal Growth in the Dimorphic Yeast Yarrowia lipolytica

    PubMed Central

    Hurtado, Cleofe A. R.; Beckerich, Jean-Marie; Gaillardin, Claude; Rachubinski, Richard A.

    2000-01-01

    Dimorphism in fungi is believed to constitute a mechanism of response to adverse conditions and represents an important attribute for the development of virulence by a number of pathogenic fungal species. We have isolated YlRAC1, a gene encoding a 192-amino-acid protein that is essential for hyphal growth in the dimorphic yeast Yarrowia lipolytica and which represents the first Rac homolog described for fungi. YlRAC1 is not an essential gene, and its deletion does not affect the ability to mate or impair actin polarization in Y. lipolytica. However, strains lacking functional YlRAC1 show alterations in cell morphology, suggesting that the function of YlRAC1 may be related to some aspect of the polarization of cell growth. Northern blot analysis showed that transcription of YlRAC1 increases steadily during the yeast-to-hypha transition, while Southern blot analysis of genomic DNA suggested the presence of several RAC family members in Y. lipolytica. Interestingly, strains lacking functional YlRAC1 are still able to grow as the pseudohyphal form and to invade agar, thus pointing to a function for YlRAC1 downstream of MHY1, a previously isolated gene encoding a C2H2-type zinc finger protein with the ability to bind putative stress response elements and whose activity is essential for both hyphal and pseudohyphal growth in Y. lipolytica. PMID:10762235

  8. Means of Effective Security Sector Reform: A Comparison of US Military and Contractor Programs

    DTIC Science & Technology

    2011-05-19

    the US Army took over 400 suspension / debarment actions in fiscal year 2010.65 GAO report 11-419T, Foreign Operations: Key Issues for Congressional...Contracting, Ensuring Contractor Accountability: Past Performance and Suspension & Debartment, Testimony, (Washington, D.C.: Commission on Wartime...64 Ibid., 8. 65 Commission on Wartime Contracting, Ensuring Contractor Accountability: Past Performance and Suspension

  9. Report on audit of Department of Energy`s contractor salary increase fund

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    1997-04-04

    The Department of Energy (Department) uses contractors to operate its facilities and compensates contractor employees based on their skills, complexity of jobs, and work performance. Thirty-one of the Department`s major contractors reported a total payroll of $4.3 billion and $4.4 billion during 1994 and 1995, respectively. The 31 contractors also reported awarding salary increases of $18 million for 1994 and $200 million for 1995. The purpose of the audit was to review the process used to determine and approve the amount of salary increases for contractor employees. The specific audit objective was to determine whether salary increases received by contractormore » employees were in accordance with Departmental policies and procedures. The Department of Energy Acquisition Regulation (DEAR) requires that contractor salary actions be within specific limitations, supportable, and approved prior to incurrence of costs. In addition, the Secretary of Energy imposed a 1 year salary freeze on the merit portion of management and operating contractor employee salaries for each contractor`s Fiscal Year 1994 compensation year. However, a fund for promotions and adjustments was approved but limited to 0.5 percent of payroll for the year. A review of eight major contractors showed that six complied with the Department`s policies on salary increases. The other two gave salary increases that were not always in accordance with Departmental policies. This resulted in both contractors not fully complying with the pay freeze in 1994 and exceeding their salary increase fund budgets in 1995. If these two contractors had implemented Department and contract requirements and contracting officers had properly performed their contract administrative responsibilities concerning salary increase funds, both contractors would have frozen salary increases and would not have exceeded their annual budgets.« less

  10. Mena associates with Rac1 and modulates connexin 43 remodeling in cardiomyocytes

    PubMed Central

    Ram, Rashmi; Wescott, Andrew P.; Varandas, Katherine; Dirksen, Robert T.

    2013-01-01

    Mena, a member of the Ena/VASP family of actin regulatory proteins, modulates microfilaments and interacts with cytoskeletal proteins associated with heart failure. Mena is localized at the intercalated disc (ICD) of adult cardiac myocytes, colocalizing with numerous cytoskeletal proteins. Mena's role in the maintainence of mechanical myocardial stability at the cardiomyocyte ICD remains unknown. We hypothesized that Mena may modulate signals from the sarcolemma to the actin cytoskeleton at the ICD to regulate the expression and localization of connexin 43 (Cx43). The small GTPase Rac1 plays a pivotal role in the regulation of actin cytoskeletal reorganization and mediating morphological and transcriptional changes in cardiomyocytes. We found that Mena is associated with active Rac1 in cardiomyocytes and that RNAi knockdown of Mena increased Rac1 activity significantly. Furthermore, Mena knockdown increased Cx43 expression and altered Cx43 localization and trafficking at the ICD, concomitant with faster intercellular communication, as assessed by dye transfer between cardiomyocyte pairs. In mice overexpressing constitutively active Rac1, left ventricular Mena expression was increased significantly, concomitant with lateral redistribution of Cx43. These results suggest that Mena is a critical regulator of the ICD and is required for normal localization of Cx43 in part via regulation of Rac1. PMID:24186093

  11. Mena associates with Rac1 and modulates connexin 43 remodeling in cardiomyocytes.

    PubMed

    Ram, Rashmi; Wescott, Andrew P; Varandas, Katherine; Dirksen, Robert T; Blaxall, Burns C

    2014-01-01

    Mena, a member of the Ena/VASP family of actin regulatory proteins, modulates microfilaments and interacts with cytoskeletal proteins associated with heart failure. Mena is localized at the intercalated disc (ICD) of adult cardiac myocytes, colocalizing with numerous cytoskeletal proteins. Mena's role in the maintainence of mechanical myocardial stability at the cardiomyocyte ICD remains unknown. We hypothesized that Mena may modulate signals from the sarcolemma to the actin cytoskeleton at the ICD to regulate the expression and localization of connexin 43 (Cx43). The small GTPase Rac1 plays a pivotal role in the regulation of actin cytoskeletal reorganization and mediating morphological and transcriptional changes in cardiomyocytes. We found that Mena is associated with active Rac1 in cardiomyocytes and that RNAi knockdown of Mena increased Rac1 activity significantly. Furthermore, Mena knockdown increased Cx43 expression and altered Cx43 localization and trafficking at the ICD, concomitant with faster intercellular communication, as assessed by dye transfer between cardiomyocyte pairs. In mice overexpressing constitutively active Rac1, left ventricular Mena expression was increased significantly, concomitant with lateral redistribution of Cx43. These results suggest that Mena is a critical regulator of the ICD and is required for normal localization of Cx43 in part via regulation of Rac1.

  12. Bretylium potentiation of the contractor responses of isolated rabbit aortic strips to potassium and tyramine

    PubMed Central

    Kurahashi, K.; Shibata, S.

    1971-01-01

    1. Pretreatment of rabbit aortic strips with bretylium potentiated the contractor response to potassium and tyramine but not to noradrenaline. On the other hand, such pretreatment inhibited the response to nicotine. 2. Even in reserpinized or cold stored aortic strips, pretreatment with bretylium enhanced the contractor response to potassium and tyramine. 3. Pretreatment of fresh, reserpinized, or cold stored aortic strips with pheniprazine potentiated the contractor response to potassium and tyramine. 4. Pretreatment of aortic strips with bretylium or pheniprazine did not potentiate the response to 5-hydroxytryptamine (5-HT). 5. The results indicate that both bretylium and pheniprazine potentiate the action of tyramine and potassium, not by presynaptic mechanisms, but by postsynaptic action, causing an increase in the sensitivity of the effector cells to the stimulants. PMID:4400183

  13. The Drosophila small GTPase Rac2 is required for normal feeding and mating behaviour.

    PubMed

    Goergen, Philip; Kasagiannis, Anna; Schiöth, Helgi B; Williams, Michael J

    2014-03-01

    All multicellular organisms require the ability to regulate bodily processes in order to maintain a stable condition, which necessitates fluctuations in internal metabolics, as well as modifications of outward behaviour. Understanding the genetics behind this modulation is important as a general model for the metabolic modification of behaviour. This study demonstrates that the activity of the small GTPase Rac2 is required in Drosophila for the proper regulation of lipid storage and feeding behaviour, as well as aggression and mating behaviours. Rac2 mutant males and females are susceptible to starvation and contain considerably less lipids than controls. Furthermore, Rac2 mutants also have disrupted feeding behaviour, eating fewer but larger meals than controls. Intriguingly, Rac2 mutant males rarely initiate aggressive behaviour and display significantly increased levels of courtship behaviour towards other males and mated females. From these results we conclude that Rac2 has a central role in regulating the Drosophila homeostatic system.

  14. Exome sequencing identifies recurrent somatic RAC1 mutations in melanoma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Krauthammer, Michael; Kong, Yong; Ha, Byung Hak

    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 frequentmore » 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.« less

  15. RAC1b overexpression stimulates proliferation and NF-kB-mediated anti-apoptotic signaling in thyroid cancer cells

    PubMed Central

    Faria, Márcia; Matos, Paulo; Pereira, Teresa; Cabrera, Rafael; Cardoso, Bruno A.; Bugalho, Maria João

    2017-01-01

    Overexpression of tumor-associated RAC1b has been recently highlighted as one of the most promising targets for therapeutic intervention in colon, breast, lung and pancreatic cancer. RAC1b is a hyperactive variant of the small GTPase RAC1 and has been recently shown to be overexpressed in a subset of papillary thyroid carcinomas associated with unfavorable outcome. Using the K1 PTC derived cell line as an in vitro model, we observed that both RAC1 and RAC1b were able to induce a significant increase on NF-kB and cyclin D1 reporter activity. A clear p65 nuclear localization was found in cells transfected with RAC1b-WT, confirming NF-kB canonical pathway activation. Consistently, we observed a RAC1b-mediated decrease in IκBα (NF-kB inhibitor) protein levels. Moreover, we show that RAC1b overexpression stimulates G1/S progression and protects thyroid cells against induced apoptosis, the latter through a process involving the NF-kB pathway. Present data support previous findings suggesting an important role for RAC1b in the development of follicular cell-derived thyroid malignancies and point out NF-kB activation as one of the molecular mechanisms associated with the pro-tumorigenic advantage of RAC1b overexpression in thyroid carcinomas. PMID:28234980

  16. 10 CFR 436.33 - Procedures and methods for contractor selection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... for contractor selection. (a) Competitive selection. Competitive selections based on solicitation of... synopsizes the proposed contract action. (2) Each competitive solicitation— (i) Shall request technical and... from those within the competitive range. (b) Unsolicited proposals. Federal agencies may— (1) Consider...

  17. Two distinct mTORC2-dependent pathways converge on Rac1 to drive breast cancer metastasis.

    PubMed

    Morrison Joly, Meghan; Williams, Michelle M; Hicks, Donna J; Jones, Bayley; Sanchez, Violeta; Young, Christian D; Sarbassov, Dos D; Muller, William J; Brantley-Sieders, Dana; Cook, Rebecca S

    2017-06-30

    The importance of the mTOR complex 2 (mTORC2) signaling complex in tumor progression is becoming increasingly recognized. HER2-amplified breast cancers use Rictor/mTORC2 signaling to drive tumor formation, tumor cell survival and resistance to human epidermal growth factor receptor 2 (HER2)-targeted therapy. Cell motility, a key step in the metastatic process, can be activated by mTORC2 in luminal and triple negative breast cancer cell lines, but its role in promoting metastases from HER2-amplified breast cancers is not yet clear. Because Rictor is an obligate cofactor of mTORC2, we genetically engineered Rictor ablation or overexpression in mouse and human HER2-amplified breast cancer models for modulation of mTORC2 activity. Signaling through mTORC2-dependent pathways was also manipulated using pharmacological inhibitors of mTOR, Akt, and Rac. Signaling was assessed by western analysis and biochemical pull-down assays specific for Rac-GTP and for active Rac guanine nucleotide exchange factors (GEFs). Metastases were assessed from spontaneous tumors and from intravenously delivered tumor cells. Motility and invasion of cells was assessed using Matrigel-coated transwell assays. We found that Rictor ablation potently impaired, while Rictor overexpression increased, metastasis in spontaneous and intravenously seeded models of HER2-overexpressing breast cancers. Additionally, migration and invasion of HER2-amplified human breast cancer cells was diminished in the absence of Rictor, or upon pharmacological mTOR kinase inhibition. Active Rac1 was required for Rictor-dependent invasion and motility, which rescued invasion/motility in Rictor depleted cells. Rictor/mTORC2-dependent dampening of the endogenous Rac1 inhibitor RhoGDI2, a factor that correlated directly with increased overall survival in HER2-amplified breast cancer patients, promoted Rac1 activity and tumor cell invasion/migration. The mTORC2 substrate Akt did not affect RhoGDI2 dampening, but partially

  18. Expression and activity of Rac1 is negatively affected in the dehydroepiandrosterone induced polycystic ovary of mouse

    PubMed Central

    2014-01-01

    Background Polycystic ovarian syndrome (PCOS) is characterized by the presence of multiple follicular cysts, giving rise to infertility due to anovulation. This syndrome affects about 10% of women, worldwide. The exact molecular mechanism leading to PCOS remains obscure. RhoGTPase has been associated with oogenesis, but its role in PCOS remains unexplored. Therefore, we attempted to elucidate the Vav-Rac1 signaling in PCOS mice model. Methods We generated a PCOS mice model by injecting dehydroepiandrosterone (DHEA) for a period of 20 days. The expression levels of Rac1, pRac1, Vav, pVav and Caveolin1 were analyzed by employing immuno-blotting and densitometry. The association between Vav and Rac1 proteins were studied by immuno-precipitation. Furthermore, we analyzed the activity of Rac1 and levels of inhibin B and 17β-estradiol in ovary using biochemical assays. Results The presence of multiple follicular cysts in ovary were confirmed by histology. The activity of Rac1 (GTP bound state) was significantly reduced in the PCOS ovary. Similarly, the expression levels of Rac1 and its phosphorylated form (pRac1) were decreased in PCOS in comparison to the sham ovary. The expression level and activity (phosphorylated form) of guanine nucleotide exchanger of Rac1, Vav, was moderately down-regulated. We observed comparatively increased expressions of Caveolin1, 17β-estradiol, and inhibin B in the polycystic ovary. Conclusion We conclude that hyperandrogenization (PCOS) by DHEA diminishes ovarian Rac1 and Vav expression and activity along with an increase in expression of Caveolin1. This is accompanied by an increase in the intra-ovarian level of '17 β-estradiol and inhibin B. PMID:24628852

  19. Epidermal Rac1 regulates the DNA damage response and protects from UV-light-induced keratinocyte apoptosis and skin carcinogenesis

    PubMed Central

    Deshmukh, Jayesh; Pofahl, Ruth; Haase, Ingo

    2017-01-01

    Non-melanoma skin cancer (NMSC) is the most common type of cancer. Increased expression and activity of Rac1, a small Rho GTPase, has been shown previously in NMSC and other human cancers; suggesting that Rac1 may function as an oncogene in skin. DMBA/TPA skin carcinogenesis studies in mice have shown that Rac1 is required for chemically induced skin papilloma formation. However, UVB radiation by the sun, which causes DNA damage, is the most relevant cause for NMSC. A potential role of Rac1 in UV-light-induced skin carcinogenesis has not been investigated so far. To investigate this, we irradiated mice with epidermal Rac1 deficiency (Rac1-EKO) and their controls using a well-established protocol for long-term UV-irradiation. Most of the Rac1-EKO mice developed severe skin erosions upon long-term UV-irradiation, unlike their controls. These skin erosions in Rac1-EKO mice healed subsequently. Surprisingly, we observed development of squamous cell carcinomas (SCCs) within the UV-irradiation fields. This shows that the presence of Rac1 in the epidermis protects from UV-light-induced skin carcinogenesis. Short-term UV-irradiation experiments revealed increased UV-light-induced apoptosis of Rac1-deficient epidermal keratinocytes in vitro as well as in vivo. Further investigations using cyclobutane pyrimidine dimer photolyase transgenic mice revealed that the observed increase in UV-light-induced keratinocyte apoptosis in Rac1-EKO mice is DNA damage dependent and correlates with caspase-8 activation. Furthermore, Rac1-deficient keratinocytes showed reduced levels of p53, γ-H2AX and p-Chk1 suggesting an attenuated DNA damage response upon UV-irradiation. Taken together, our data provide direct evidence for a protective role of Rac1 in UV-light-induced skin carcinogenesis and keratinocyte apoptosis probably through regulating mechanisms of the DNA damage response and repair pathways. PMID:28277539

  20. Epidermal Rac1 regulates the DNA damage response and protects from UV-light-induced keratinocyte apoptosis and skin carcinogenesis.

    PubMed

    Deshmukh, Jayesh; Pofahl, Ruth; Haase, Ingo

    2017-03-09

    Non-melanoma skin cancer (NMSC) is the most common type of cancer. Increased expression and activity of Rac1, a small Rho GTPase, has been shown previously in NMSC and other human cancers; suggesting that Rac1 may function as an oncogene in skin. DMBA/TPA skin carcinogenesis studies in mice have shown that Rac1 is required for chemically induced skin papilloma formation. However, UVB radiation by the sun, which causes DNA damage, is the most relevant cause for NMSC. A potential role of Rac1 in UV-light-induced skin carcinogenesis has not been investigated so far. To investigate this, we irradiated mice with epidermal Rac1 deficiency (Rac1-EKO) and their controls using a well-established protocol for long-term UV-irradiation. Most of the Rac1-EKO mice developed severe skin erosions upon long-term UV-irradiation, unlike their controls. These skin erosions in Rac1-EKO mice healed subsequently. Surprisingly, we observed development of squamous cell carcinomas (SCCs) within the UV-irradiation fields. This shows that the presence of Rac1 in the epidermis protects from UV-light-induced skin carcinogenesis. Short-term UV-irradiation experiments revealed increased UV-light-induced apoptosis of Rac1-deficient epidermal keratinocytes in vitro as well as in vivo. Further investigations using cyclobutane pyrimidine dimer photolyase transgenic mice revealed that the observed increase in UV-light-induced keratinocyte apoptosis in Rac1-EKO mice is DNA damage dependent and correlates with caspase-8 activation. Furthermore, Rac1-deficient keratinocytes showed reduced levels of p53, γ-H2AX and p-Chk1 suggesting an attenuated DNA damage response upon UV-irradiation. Taken together, our data provide direct evidence for a protective role of Rac1 in UV-light-induced skin carcinogenesis and keratinocyte apoptosis probably through regulating mechanisms of the DNA damage response and repair pathways.

  1. 6-Mercaptopurine reduces macrophage activation and gut epithelium proliferation through inhibition of GTPase Rac1.

    PubMed

    Marinković, Goran; Hamers, Anouk A J; de Vries, Carlie J M; de Waard, Vivian

    2014-09-01

    Inflammatory bowel disease is characterized by chronic intestinal inflammation. Azathioprine and its metabolite 6-mercaptopurine (6-MP) are effective immunosuppressive drugs that are widely used in patients with inflammatory bowel disease. However, established understanding of their immunosuppressive mechanism is limited. Azathioprine and 6-MP have been shown to affect small GTPase Rac1 in T cells and endothelial cells, whereas the effect on macrophages and gut epithelial cells is unknown. Macrophages (RAW cells) and gut epithelial cells (Caco-2 cells) were activated by cytokines and the effect on Rac1 signaling was assessed in the presence or absence of 6-MP. Rac1 is activated in macrophages and epithelial cells, and treatment with 6-MP resulted in Rac1 inhibition. In macrophages, interferon-γ induced downstream signaling through c-Jun-N-terminal Kinase (JNK) resulting in inducible nitric oxide synthase (iNOS) expression. iNOS expression was reduced by 6-MP in a Rac1-dependent manner. In epithelial cells, 6-MP efficiently inhibited tumor necrosis factor-α-induced expression of the chemokines CCL2 and interleukin-8, although only interleukin-8 expression was inhibited in a Rac1-dependent manner. In addition, activation of the transcription factor STAT3 was suppressed in a Rac1-dependent fashion by 6-MP, resulting in reduced proliferation of the epithelial cells due to diminished cyclin D1 expression. These data demonstrate that 6-MP affects macrophages and gut epithelial cells beneficially, in addition to T cells and endothelial cells. Furthermore, mechanistic insight is provided to support development of Rac1-specific inhibitors for clinical use in inflammatory bowel disease.

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

    PubMed Central

    Thamilselvan, Vijayalakshmi; Menon, Mani

    2013-01-01

    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. PMID:21814770

  4. 20 CFR 401.90 - Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Contractors. 401.90 Section 401.90 Employees... Privacy Act § 401.90 Contractors. (a) All contracts which require a contractor to maintain, or on behalf... requiring the contractor to comply with the Privacy Act and this part. (b) A contractor and any employee of...

  5. bFGF Regulates PI3-Kinase-Rac1-JNK Pathway and Promotes Fibroblast Migration in Wound Healing

    PubMed Central

    Kanazawa, Shigeyuki; Fujiwara, Toshihiro; Matsuzaki, Shinsuke; Shingaki, Kenta; Taniguchi, Manabu; Miyata, Shingo; Tohyama, Masaya; Sakai, Yasuo; Yano, Kenji; Hosokawa, Ko; Kubo, Tateki

    2010-01-01

    Fibroblast proliferation and migration play important roles in wound healing. bFGF is known to promote both fibroblast proliferation and migration during the process of wound healing. However, the signal transduction of bFGF-induced fibroblast migration is still unclear, because bFGF can affect both proliferation and migration. Herein, we investigated the effect of bFGF on fibroblast migration regardless of its effect on fibroblast proliferation. We noticed involvement of the small GTPases of the Rho family, PI3-kinase, and JNK. bFGF activated RhoA, Rac1, PI3-kinase, and JNK in cultured fibroblasts. Inhibition of RhoA did not block bFGF-induced fibroblast migration, whereas inhibition of Rac1, PI3-kinase, or JNK blocked the fibroblast migration significantly. PI3-kinase-inhibited cells down-regulated the activities of Rac1 and JNK, and Rac1-inhibited cells down-regulated JNK activity, suggesting that PI3-kinase is upstream of Rac1 and that JNK is downstream of Rac1. Thus, we concluded that PI3-kinase, Rac1, and JNK were essential for bFGF-induced fibroblast migration, which is a novel pathway of bFGF-induced cell migration. PMID:20808927

  6. Defense Primer: DOD Contractors

    DTIC Science & Technology

    2017-02-10

    contractors . A defense contractor , as defined by the Code of Federal Regulations, is “any individual, firm, corporation, partnership, association...158.3, “Definitions”). Within the defense policy community, the term contractor is commonly used in two different contexts. The word can describe

  7. Relevance of small GTPase Rac1 pathway in drug and radio-resistance mechanisms: Opportunities in cancer therapeutics.

    PubMed

    Cardama, G A; Alonso, D F; Gonzalez, N; Maggio, J; Gomez, D E; Rolfo, C; Menna, P L

    2018-04-01

    Rac1 GTPase signaling pathway has a critical role in the regulation of a plethora of cellular functions governing cancer cell behavior. Recently, it has been shown a critical role of Rac1 in the emergence of resistance mechanisms to cancer therapy. This review describes the current knowledge regarding Rac1 pathway deregulation and its association with chemoresistance, radioresistance, resistance to targeted therapies and immune evasion. This supports the idea that interfering Rac1 signaling pathway could be an interesting approach to tackle cancer resistance. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. 25 CFR 900.188 - To what extent shall the contractor cooperate with the Federal government in connection with tort...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES CONTRACTS UNDER THE INDIAN SELF-DETERMINATION AND EDUCATION... of a self-determination contract or subcontract. (c) The contractor, through its designated tort... the Federal government undertakes the settlement or defense of any claim or action the contractor...

  9. 25 CFR 900.188 - To what extent shall the contractor cooperate with the Federal government in connection with tort...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES CONTRACTS UNDER THE INDIAN SELF-DETERMINATION AND EDUCATION... of a self-determination contract or subcontract. (c) The contractor, through its designated tort... the Federal government undertakes the settlement or defense of any claim or action the contractor...

  10. 25 CFR 900.188 - To what extent shall the contractor cooperate with the Federal government in connection with tort...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES CONTRACTS UNDER THE INDIAN SELF-DETERMINATION AND EDUCATION... of a self-determination contract or subcontract. (c) The contractor, through its designated tort... the Federal government undertakes the settlement or defense of any claim or action the contractor...

  11. 25 CFR 900.188 - To what extent shall the contractor cooperate with the Federal government in connection with tort...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES CONTRACTS UNDER THE INDIAN SELF-DETERMINATION AND EDUCATION... of a self-determination contract or subcontract. (c) The contractor, through its designated tort... the Federal government undertakes the settlement or defense of any claim or action the contractor...

  12. RhoB controls endothelial barrier recovery by inhibiting Rac1 trafficking to the cell border

    PubMed Central

    Marcos-Ramiro, Beatriz; García-Weber, Diego; Barroso, Susana; Feito, Jorge; Ortega, María C.; Cernuda-Morollón, Eva; Reglero-Real, Natalia; Fernández-Martín, Laura; Durán, Maria C.; Alonso, Miguel A.; Correas, Isabel; Cox, Susan; Ridley, Anne J.

    2016-01-01

    Endothelial barrier dysfunction underlies chronic inflammatory diseases. In searching for new proteins essential to the human endothelial inflammatory response, we have found that the endosomal GTPase RhoB is up-regulated in response to inflammatory cytokines and expressed in the endothelium of some chronically inflamed tissues. We show that although RhoB and the related RhoA and RhoC play additive and redundant roles in various aspects of endothelial barrier function, RhoB specifically inhibits barrier restoration after acute cell contraction by preventing plasma membrane extension. During barrier restoration, RhoB trafficking is induced between vesicles containing RhoB nanoclusters and plasma membrane protrusions. The Rho GTPase Rac1 controls membrane spreading and stabilizes endothelial barriers. We show that RhoB colocalizes with Rac1 in endosomes and inhibits Rac1 activity and trafficking to the cell border during barrier recovery. Inhibition of endosomal trafficking impairs barrier reformation, whereas induction of Rac1 translocation to the plasma membrane accelerates it. Therefore, RhoB-specific regulation of Rac1 trafficking controls endothelial barrier integrity during inflammation. PMID:27138256

  13. Augmented Rac1 Expression and Activity are Associated with Oxidative Stress and Decline of β Cell Function in Obesity.

    PubMed

    Zhou, Shutong; Yu, Dongni; Ning, Shangyong; Zhang, Heli; Jiang, Lei; He, Lei; Li, Miao; Sun, Mingxiao

    2015-01-01

    The aim of this study was to clarify the relationship among Rac1 expression and activation, oxidative stress and β cell dysfunction in obesity. In vivo, serum levels of glucose, insulin, oxidative stress markers and Rac1 expression were compared between ob/ob mice and C57BL/6J controls. Then, these variables were rechecked after the administration of the specific Rac1 inhibitor-NSC23766 in ob/ob mice. In vitro, NIT-1 β cells were cultured in a hyperglycemic and/or hyperlipidemic state with or without NSC23766, and the differences of Rac1 expression and translocation, NADPH oxidase(Nox) enzyme activity, reactive oxygen species (ROS) and insulin mRNA were observed. ob/ob mice displayed abnormal glycometabolism, oxidative stress and excessive expression of Rac1 in the pancreas. NSC23766 injection inhibited the expression of Rac1 in the pancreas, along with amelioration of oxidative stress and glycometabolism in obese mice. Under hyperglycemic and/or hyperlipidemic conditions, Rac1 translocated to the cellular membrane, induced activation of the NADPH oxidase enzyme and oxidative stress, and simultaneously reduced the insulin mRNA expression in NIT-1 β cells. Inhibiting Rac1 activity could alleviate oxidative stress and meliorate the decline of insulin mRNA in β cells. Rac1 might contribute to oxidative stress systemically and locally in the pancreas in obesity. The excessive activation and expression of Rac1 in obesity were associated with β cell dysfunction through ROS production. © 2015 S. Karger AG, Basel.

  14. Rac1 GTPase -deficient mouse lens exhibits defects in shape, suture formation, fiber cell migration and survival

    PubMed Central

    Maddala, Rupalatha; Chauhan, Bharesh K.; Walker, Christopher; Zheng, Yi; Robinson, Michael L.; Lang, Richard A.; Rao, Ponugoti V.

    2011-01-01

    Morphogenesis and shape of the ocular lens depend on epithelial cell elongation and differentiation into fiber cells, followed by the symmetric and compact organization of fiber cells within an enclosed extracellular matrix-enriched elastic capsule. The cellular mechanisms orchestrating these different events however, remain obscure. We investigated the role of the Rac1 GTPase in these processes by targeted deletion of expression using the conditional gene knockout (cKO) approach. Rac1 cKO mice were derived from two different Cre (Le-Cre and MLR-10) transgenic mice in which lens-specific Cre expression starts at embryonic day 8.75 and 10.5, respectively, in both the lens epithelium and fiber cells. The Le-Cre/Rac1 cKO mice exhibited an early-onset (E12.5) and severe lens phenotype compared to the MLR-10/Rac1 cKO (E15.5) mice. While the Le-Cre/Rac1 cKO lenses displayed delayed primary fiber cell elongation, lenses from both Rac1 cKO strains were characterized by abnormal shape, impaired secondary fiber cell migration, sutural defects and thinning of the posterior capsule which often led to rupture. Lens fiber cell N-cadherin/β-catenin/Rap1/Nectin-based cell-cell junction formation and WAVE-2/Abi-2/Nap1-regulated actin polymerization were impaired in the Rac1 deficient mice. Additionally, the Rac1 cKO lenses were characterized by a shortened epithelial sheet, reduced levels of extracellular matrix (ECM) proteins and increased apoptosis. Taken together, these data uncover the essential role of Rac1 GTPase activity in establishment and maintenance of lens shape, suture formation and capsule integrity, and in fiber cell migration, adhesion and survival, via regulation of actin cytoskeletal dynamics, cell adhesive interactions and ECM turnover. PMID:21945075

  15. 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

  16. 22 CFR 136.6 - Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Contractors. 136.6 Section 136.6 Foreign... Contractors. To the extent that contractors enjoy importation or tax privileges in a foreign country because... provisions in their contracts that require the contractors to observe the requirements of these regulations...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., development, maintenance, and operation of Spanish-American installations and facilities. (b) The Contractor... this contract by reference. (c) The Contractor shall apply to the appropriate Spanish authorities for approval of status as a Direct Contractor in order to complete duty-free import of non-Spanish equipment...

  18. 78 FR 58613 - Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors Regarding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-24

    ... for age and race in a regression analysis. Using America Community Survey (ACS) data and conducting a.... All models were run using the American Community Survey 2008-2010 Public Use Microdata (PUMS). The... that contractors maintain several quantitative measurements and comparisons for the number of veterans...

  19. Rac1 Guides Porf-2 to Wnt Pathway to Mediate Neural Stem Cell Proliferation

    PubMed Central

    Yang, Xi-Tao; Huang, Guo-Hui; Li, Hong-Jiang; Sun, Zhao-Liang; Xu, Nan-Jie; Feng, Dong-Fu

    2017-01-01

    The molecular and cellular mechanisms underlying the anti-proliferative effects of preoptic regulator factor 2 (Porf-2) on neural stem cells (NSCs) remain largely unknown. Here, we found that Porf-2 inhibits the activity of ras-related C3 botulinum toxin substrate 1 (Rac1) protein in hippocampus-derived rat NSCs. Reduced Rac1 activity impaired the nuclear translocation of β-catenin, ultimately causing a repression of NSCs proliferation. Porf-2 knockdown enhanced NSCs proliferation but not in the presence of small molecule inhibitors of Rac1 or Wnt. At the same time, the repression of NSCs proliferation caused by Porf-2 overexpression was counteracted by small molecule activators of Rac1 or Wnt. By using a rat optic nerve crush model, we observed that Porf-2 knockdown enhanced the recovery of visual function. In particular, optic nerve injury in rats led to increased Wnt family member 3a (Wnt3a) protein expression, which we found responsible for enhancing Porf-2 knockdown-induced NSCs proliferation. These findings suggest that Porf-2 exerts its inhibitory effect on NSCs proliferation via Rac1-Wnt/β-catenin pathway. Porf-2 may therefore represent and interesting target for optic nerve injury recovery and therapy. PMID:28626389

  20. 7 CFR 1788.12 - Contractors' bonds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Contractors' bonds. 1788.12 Section 1788.12... Insurance for Contractors, Engineers, and Architects, Electric Borrowers § 1788.12 Contractors' bonds. Electric borrowers shall require contractors to obtain contractors' bonds when required by part 1726...

  1. The Transcriptomic Signature of RacA Activation and Inactivation Provides New Insights into the Morphogenetic Network of Aspergillus niger

    PubMed Central

    Kwon, Min Jin; Nitsche, Benjamin M.; Arentshorst, Mark; Jørgensen, Thomas R.; Ram, Arthur F. J.; Meyer, Vera

    2013-01-01

    RacA is the main Rho GTPase in Aspergillus niger regulating polarity maintenance via controlling actin dynamics. Both deletion and dominant activation of RacA (RacG18V) provoke an actin localization defect and thereby loss of polarized tip extension, resulting in frequent dichotomous branching in the ΔracA strain and an apolar growing phenotype for RacG18V. In the current study the transcriptomics and physiological consequences of these morphological changes were investigated and compared with the data of the morphogenetic network model for the dichotomous branching mutant ramosa-1. This integrated approach revealed that polar tip growth is most likely orchestrated by the concerted activities of phospholipid signaling, sphingolipid signaling, TORC2 signaling, calcium signaling and CWI signaling pathways. The transcriptomic signatures and the reconstructed network model for all three morphology mutants (ΔracA, RacG18V, ramosa-1) imply that these pathways become integrated to bring about different physiological adaptations including changes in sterol, zinc and amino acid metabolism and changes in ion transport and protein trafficking. Finally, the fate of exocytotic (SncA) and endocytotic (AbpA, SlaB) markers in the dichotomous branching mutant ΔracA was followed, demonstrating that hyperbranching does not per se result in increased protein secretion. PMID:23894378

  2. 78 FR 58681 - Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors Regarding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-24

    ... Community Survey (ACS) 2008- 2010 Public Use Microdata (PUMS), and controlling for age and race we found... employment practices. Require contractors to maintain several quantitative measurements and comparisons for... into jobs and pay taxes. \\9\\ U.S. Census Bureau, 2011 American Community Survey. There are a variety of...

  3. 76 FR 77055 - Affirmative Action and Nondiscrimination Obligations of Contractors and Subcontractors Regarding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-09

    ... asserted that quantitative and measurable analyses similar to those for minorities and women were needed to... provided few details about the design or operation of the California State program, and that, consequently... recommended that the contractor be required to invite voluntary self- identification at both the pre- and post...

  4. Interactions of UNC-34 Enabled With Rac GTPases and the NIK Kinase MIG-15 in Caenorhabditis elegans Axon Pathfinding and Neuronal Migration

    PubMed Central

    Shakir, M. Afaq; Gill, Jason S.; Lundquist, Erik A.

    2006-01-01

    Many genes that affect axon pathfinding and cell migration have been identified. Mechanisms by which these genes and the molecules they encode interact with one another in pathways and networks to control developmental events are unclear. Rac GTPases, the cytoskeletal signaling molecule Enabled, and NIK kinase have all been implicated in regulating axon pathfinding and cell migration. Here we present evidence that, in Caenorhabditis elegans, three Rac GTPases, CED-10, RAC-2, and MIG-2, define three redundant pathways that each control axon pathfinding, and that the NIK kinase MIG-15 acts in each Rac pathway. Furthermore, we show that the Enabled molecule UNC-34 defines a fourth partially redundant pathway that acts in parallel to Rac/MIG-15 signaling in axon pathfinding. Enabled and the three Racs also act redundantly to mediate AQR and PQR neuronal cell migration. The Racs and UNC-34 Ena might all control the formation of actin-based protrusive structures (lamellipodia and filopodia) that mediate growth cone outgrowth and cell migration. MIG-15 does not act with the three Racs in execution of cell migration. Rather, MIG-15 affects direction of PQR neuronal migration, similar to UNC-40 and DPY-19, which control initial Q cell polarity, and Wnt signaling, which acts later to control Q cell-directed migration. MIG-2 Rac, which acts with CED-10 Rac, RAC-2 Rac, and UNC-34 Ena in axon pathfinding and cell migration, also acts with MIG-15 in PQR directional migration. PMID:16204220

  5. Mib1 contributes to persistent directional cell migration by regulating the Ctnnd1-Rac1 pathway.

    PubMed

    Mizoguchi, Takamasa; Ikeda, Shoko; Watanabe, Saori; Sugawara, Michiko; Itoh, Motoyuki

    2017-10-31

    Persistent directional cell migration is involved in animal development and diseases. The small GTPase Rac1 is involved in F-actin and focal adhesion dynamics. Local Rac1 activity is required for persistent directional migration, whereas global, hyperactivated Rac1 enhances random cell migration. Therefore, precise control of Rac1 activity is important for proper directional cell migration. However, the molecular mechanism underlying the regulation of Rac1 activity in persistent directional cell migration is not fully understood. Here, we show that the ubiquitin ligase mind bomb 1 (Mib1) is involved in persistent directional cell migration. We found that knockdown of MIB1 led to an increase in random cell migration in HeLa cells in a wound-closure assay. Furthermore, we explored novel Mib1 substrates for cell migration and found that Mib1 ubiquitinates Ctnnd1. Mib1-mediated ubiquitination of Ctnnd1 K547 attenuated Rac1 activation in cultured cells. In addition, we found that posterior lateral line primordium cells in the zebrafish mib1 ta52b mutant showed increased random migration and loss of directional F-actin-based protrusion formation. Knockdown of Ctnnd1 partially rescued posterior lateral line primordium cell migration defects in the mib1 ta52b mutant. Taken together, our data suggest that Mib1 plays an important role in cell migration and that persistent directional cell migration is regulated, at least in part, by the Mib1-Ctnnd1-Rac1 pathway. Published under the PNAS license.

  6. Rac1/RhoA antagonism defines cell-to-cell heterogeneity during epidermal morphogenesis in nematodes

    PubMed Central

    Ouellette, Marie-Hélène

    2016-01-01

    The antagonism between the GTPases Rac1 and RhoA controls cell-to-cell heterogeneity in isogenic populations of cells in vitro and epithelial morphogenesis in vivo. Its involvement in the regulation of cell-to-cell heterogeneity during epidermal morphogenesis has, however, never been addressed. We used a quantitative cell imaging approach to characterize epidermal morphogenesis at a single-cell level during early elongation of Caenorhabditis elegans embryos. This study reveals that a Rac1-like pathway, involving the Rac/Cdc42 guanine-exchange factor β-PIX/PIX-1 and effector PAK1/PAK-1, and a RhoA-like pathway, involving ROCK/LET-502, control the remodeling of apical junctions and the formation of basolateral protrusions in distinct subsets of hypodermal cells. In these contexts, protrusions adopt lamellipodia or an amoeboid morphology. We propose that lamella formation may reduce tension building at cell–cell junctions during morphogenesis. Cell-autonomous antagonism between these pathways enables cells to switch between Rac1- and RhoA-like morphogenetic programs. This study identifies the first case of cell-to-cell heterogeneity controlled by Rac1/RhoA antagonism during epidermal morphogenesis. PMID:27821782

  7. Optimization of WAVE2 complex–induced actin polymerization by membrane-bound IRSp53, PIP3, and Rac

    PubMed Central

    Suetsugu, Shiro; Kurisu, Shusaku; Oikawa, Tsukasa; Yamazaki, Daisuke; Oda, Atsushi; Takenawa, Tadaomi

    2006-01-01

    WAVE2 activates the actin-related protein (Arp) 2/3 complex for Rac-induced actin polymerization during lamellipodium formation and exists as a large WAVE2 protein complex with Sra1/PIR121, Nap1, Abi1, and HSPC300. IRSp53 binds to both Rac and Cdc42 and is proposed to link Rac to WAVE2. We found that the knockdown of IRSp53 by RNA interference decreased lamellipodium formation without a decrease in the amount of WAVE2 complex. Localization of WAVE2 at the cell periphery was retained in IRSp53 knockdown cells. Moreover, activated Cdc42 but not Rac weakened the association between WAVE2 and IRSp53. When we measured Arp2/3 activation in vitro, the WAVE2 complex isolated from the membrane fraction of cells was fully active in an IRSp53-dependent manner but WAVE2 isolated from the cytosol was not. Purified WAVE2 and purified WAVE2 complex were activated by IRSp53 in a Rac-dependent manner with PIP3-containing liposomes. Therefore, IRSp53 optimizes the activity of the WAVE2 complex in the presence of activated Rac and PIP3. PMID:16702231

  8. Optimization of WAVE2 complex-induced actin polymerization by membrane-bound IRSp53, PIP(3), and Rac.

    PubMed

    Suetsugu, Shiro; Kurisu, Shusaku; Oikawa, Tsukasa; Yamazaki, Daisuke; Oda, Atsushi; Takenawa, Tadaomi

    2006-05-22

    WAVE2 activates the actin-related protein (Arp) 2/3 complex for Rac-induced actin polymerization during lamellipodium formation and exists as a large WAVE2 protein complex with Sra1/PIR121, Nap1, Abi1, and HSPC300. IRSp53 binds to both Rac and Cdc42 and is proposed to link Rac to WAVE2. We found that the knockdown of IRSp53 by RNA interference decreased lamellipodium formation without a decrease in the amount of WAVE2 complex. Localization of WAVE2 at the cell periphery was retained in IRSp53 knockdown cells. Moreover, activated Cdc42 but not Rac weakened the association between WAVE2 and IRSp53. When we measured Arp2/3 activation in vitro, the WAVE2 complex isolated from the membrane fraction of cells was fully active in an IRSp53-dependent manner but WAVE2 isolated from the cytosol was not. Purified WAVE2 and purified WAVE2 complex were activated by IRSp53 in a Rac-dependent manner with PIP(3)-containing liposomes. Therefore, IRSp53 optimizes the activity of the WAVE2 complex in the presence of activated Rac and PIP(3).

  9. Membrane Environment Exerts an Important Influence on Rac-Mediated Activation of Phospholipase Cγ2 ▿ †

    PubMed Central

    Everett, Katy L.; Buehler, Anja; Bunney, Tom D.; Margineanu, Anca; Baxendale, Rhona W.; Vatter, Petra; Retlich, Michael; Walliser, Claudia; Manning, Hugh B.; Neil, Mark A. A.; Dunsby, Christopher; French, Paul M. W.; Gierschik, Peter; Katan, Matilda

    2011-01-01

    We performed analyses of the molecular mechanisms involved in the regulation of phospholipase Cγ2 (PLCγ2). We identified several regions in the PLCγ-specific array, γSA, that contribute to autoinhibition in the basal state by occlusion of the catalytic domain. While the activation of PLCγ2 by Rac2 requires stable translocation to the membrane, the removal of the domains required for membrane translocation in the context of an enzyme with impaired autoinhibition generated constitutive, highly active PLC in cells. We further tested the possibility that the interaction of PLCγ2 with its activator protein Rac2 was sufficient for activation through the release of autoinhibition. However, we found that Rac2 binding in the absence of lipid surfaces was not able to activate PLCγ2. Together with other observations, these data suggest that an important consequence of Rac2 binding and translocation to the membrane is that membrane proximity, on its own or together with Rac2, has a role in the release of autoinhibition, resulting in interfacial activation. PMID:21245382

  10. Rac1b enhances cell survival through activation of the JNK2/c-JUN/Cyclin-D1 and AKT2/MCL1 pathways

    PubMed Central

    Wang, Hong; Wei, Si-Si; Chen, Jie; Chen, Yi-He; Xu, Wei-Ping; Jie, Qi-Qiang; Zhou, Qing; Li, Yi-Gang; Wei, Yi-Dong; Wang, Yue-Peng

    2016-01-01

    Rac1b is a constitutively activated, alternatively spliced form of the small GTPase Rac1. Previous studies showed that Rac1b promotes cell proliferation and inhibits apoptosis. In the present study, we used microarray analysis to detect genes differentially expressed in HEK293T cells and SW480 human colon cancer cells stably overexpressing Rac1b. We found that the pro-proliferation genes JNK2, c-JUN and cyclin-D1 as well as anti-apoptotic AKT2 and MCL1 were all upregulated in both lines. Rac1b promoted cell proliferation and inhibited apoptosis by activating the JNK2/c-JUN/cyclin-D1 and AKT2/MCL1 pathways, respectively. Very low Rac1b levels were detected in the colonic epithelium of wild-type Sprague-Dawley rats. Knockout of the rat Rac1 gene exon-3b or knockdown of endogenous Rac1b in HT29 human colon cancer cells downregulated only the AKT2/MCL1 pathway. Our study revealed that very low levels of endogenous Rac1b inhibit apoptosis, while Rac1b upregulation both promotes cell proliferation and inhibits apoptosis. It is likely the AKT2/MCL1 pathway is more sensitive to Rac1b regulation. PMID:26918455

  11. Role of Rac1 in Escherichia coli K1 invasion of human brain microvascular endothelial cells.

    PubMed

    Rudrabhatla, Rajyalakshmi S; Selvaraj, Suresh K; Prasadarao, Nemani V

    2006-02-01

    Escherichia coli K1 invasion of human brain microvascular endothelial cells (HBMEC) requires the reorganization of host cytoskeleton at the sites of bacterial entry. Both actin and myosin constitute the cytoskeletal architecture. We have previously shown that myosin light chain (MLC) phosphorylation by MLC kinase is regulated during E. coli invasion by an upstream kinase, p21-activated kinase 1 (PAK1), which is an effector protein of Rac and Cdc42 GTPases, but not of RhoA. Here, we report that the binding of only Rac1 to PAK1 decreases in HBMEC upon infection with E. coli K1, which resulted in increased phosphorylation of MLC. Overexpression of a constitutively active (cAc) form of Rac1 in HBMEC blocked the E. coli invasion significantly, whereas overexpression of a dominant negative form had no effect. Increased PAK1 phosphorylation was observed in HBMEC expressing cAc-Rac1 with a concomitant reduction in the phosphorylation of MLC. Immunocytochemistry studies demonstrated that the inhibition of E. coli invasion into cAc-Rac1/HBMEC is due to lack of phospho-MLC recruitment to the sites of E. coli entry. Taken together the data suggest that E. coli modulates the binding of Rac1, but not Cdc42, to PAK1 during the invasion of HBMEC.

  12. Rac1 and Cdc42 GTPases regulate shear stress-driven β-catenin signaling in osteoblasts

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wan, Qiaoqiao; Cho, Eunhye; Yokota, Hiroki

    2013-04-19

    Highlights: •Shear stress increased TCF/LEF activity and stimulated β-catenin nuclear localization. •Rac1, Cdc42, and RhoA displayed distinct dynamic activity patterns under flow. •Rac1 and Cdc42, but not RhoA, regulate shear stress-driven TCF/LEF activation. •Cytoskeleton did not significantly affect shear stress-induced TCF/LEF activation. -- Abstract: Beta-catenin-dependent TCF/LEF (T-cell factor/lymphocyte enhancing factor) is known to be mechanosensitive and an important regulator for promoting bone formation. However, the functional connection between TCF/LEF activity and Rho family GTPases is not well understood in osteoblasts. Herein we investigated the molecular mechanisms underlying oscillatory shear stress-induced TCF/LEF activity in MC3T3-E1 osteoblast cells using live cell imaging.more » We employed fluorescence resonance energy transfer (FRET)-based and green fluorescent protein (GFP)-based biosensors, which allowed us to monitor signal transduction in living cells in real time. Oscillatory (1 Hz) shear stress (10 dynes/cm{sup 2}) increased TCF/LEF activity and stimulated translocation of β-catenin to the nucleus with the distinct activity patterns of Rac1 and Cdc42. The shear stress-induced TCF/LEF activity was blocked by the inhibition of Rac1 and Cdc42 with their dominant negative mutants or selective drugs, but not by a dominant negative mutant of RhoA. In contrast, constitutively active Rac1 and Cdc42 mutants caused a significant enhancement of TCF/LEF activity. Moreover, activation of Rac1 and Cdc42 increased the basal level of TCF/LEF activity, while their inhibition decreased the basal level. Interestingly, disruption of cytoskeletal structures or inhibition of myosin activity did not significantly affect shear stress-induced TCF/LEF activity. Although Rac1 is reported to be involved in β-catenin in cancer cells, the involvement of Cdc42 in β-catenin signaling in osteoblasts has not been identified. Our findings in this study

  13. Enantioselective oxidative stress and oxidative damage caused by Rac- and S-metolachlor to Scenedesmus obliquus.

    PubMed

    Liu, Huijun; Xia, YiLu; Cai, Weidan; Zhang, Yina; Zhang, Xiaoqiang; Du, Shaoting

    2017-04-01

    The rational use and environmental security of chiral pesticides has gained the interest of many researchers. The enantioselective effects of Rac- and S-metolachlor on oxidative stress in Scenedesmus obliquus were determined in this study. Stronger green fluorescence was observed in response to S-metolachlor treatment than to Rac-metolachlor treatment, suggesting that more reactive oxygen species (ROS) were stimulated by S-metolachlor. ROS levels following S-metolachlor treatment were 1.92-, 8.31-, and 1.08-times higher than those observed following Rac-metolachlor treatment at 0.1, 0.2, and 0.3 mg/L, respectively. Superoxide dismutase (SOD) and catalase (CAT) were stimulated with increasing herbicide concentrations, with S-metolachlor exhibiting a greater effect. Oxidative damage in terms of chlorophyll (Chl) content, cellular membrane permeability, and cellular ultrastructures of S. obliquus were investigated. Chla and Chlb contents in algae treated with Rac-metolachlor were 2-6-fold higher than those in algae treated with S-metolachlor at 0.1, 0.2, and 0.3 mg/L. The cellular membrane permeability of algae exposed to 0.3 mg/L Rac- and S-metolachlor was 6.19- and 42.5-times that of the control. Correlation analysis implied that ROS are the major factor responsible for the oxidative damage caused by Rac- and S-metolachlor. Damage to the chloroplasts and cell membrane of S. obliquus, low production of starch granules, and an increased number of vacuoles were observed upon ultrastructural morphology analysis by transmission electron microscope. These results indicate that S-metolachlor has a greater effect on S. obliquus than Rac-metolachlor. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Contingency Contractor Optimization Phase 3 Sustainment Software Design Document - Contingency Contractor Optimization Tool - Prototype

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Durfee, Justin David; Frazier, Christopher Rawls; Bandlow, Alisa

    This document describes the final software design of the Contingency Contractor Optimization Tool - Prototype. Its purpose is to provide the overall architecture of the software and the logic behind this architecture. Documentation for the individual classes is provided in the application Javadoc. The Contingency Contractor Optimization project is intended to address Department of Defense mandates by delivering a centralized strategic planning tool that allows senior decision makers to quickly and accurately assess the impacts, risks, and mitigation strategies associated with utilizing contract support. The Contingency Contractor Optimization Tool - Prototype was developed in Phase 3 of the OSD ATLmore » Contingency Contractor Optimization project to support strategic planning for contingency contractors. The planning tool uses a model to optimize the Total Force mix by minimizing the combined total costs for selected mission scenarios. The model optimizes the match of personnel types (military, DoD civilian, and contractors) and capabilities to meet mission requirements as effectively as possible, based on risk, cost, and other requirements.« less

  15. 7 CFR 1788.12 - Contractors' bonds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AGRICULTURE (CONTINUED) RUS FIDELITY AND INSURANCE REQUIREMENTS FOR ELECTRIC AND TELECOMMUNICATIONS BORROWERS Insurance for Contractors, Engineers, and Architects, Electric Borrowers § 1788.12 Contractors' bonds. Electric borrowers shall require contractors to obtain contractors' bonds when required by part 1726...

  16. 7 CFR 1788.12 - Contractors' bonds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AGRICULTURE (CONTINUED) RUS FIDELITY AND INSURANCE REQUIREMENTS FOR ELECTRIC AND TELECOMMUNICATIONS BORROWERS Insurance for Contractors, Engineers, and Architects, Electric Borrowers § 1788.12 Contractors' bonds. Electric borrowers shall require contractors to obtain contractors' bonds when required by part 1726...

  17. 7 CFR 1788.12 - Contractors' bonds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AGRICULTURE (CONTINUED) RUS FIDELITY AND INSURANCE REQUIREMENTS FOR ELECTRIC AND TELECOMMUNICATIONS BORROWERS Insurance for Contractors, Engineers, and Architects, Electric Borrowers § 1788.12 Contractors' bonds. Electric borrowers shall require contractors to obtain contractors' bonds when required by part 1726...

  18. 7 CFR 1788.12 - Contractors' bonds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AGRICULTURE (CONTINUED) RUS FIDELITY AND INSURANCE REQUIREMENTS FOR ELECTRIC AND TELECOMMUNICATIONS BORROWERS Insurance for Contractors, Engineers, and Architects, Electric Borrowers § 1788.12 Contractors' bonds. Electric borrowers shall require contractors to obtain contractors' bonds when required by part 1726...

  19. Rac1/Pak1/p38/MMP-2 axis regulates angiogenesis in ovarian cancer

    PubMed Central

    Gonzalez-Villasana, Vianey; Fuentes-Mattei, Enrique; Ivan, Cristina; Dalton, Heather J.; Rodriguez-Aguayo, Cristian; Fernandez-de Thomas, Ricardo J.; Aslan, Burcu; Monroig, Paloma del C.; Velazquez-Torres, Guermarie; Previs, Rebecca A.; Pradeep, Sunila; Kahraman, Nermin; Wang, Huamin; Kanlikilicer, Pinar; Ozpolat, Bulent; Calin, George; Sood, Anil K.; Lopez-Berestein, Gabriel

    2015-01-01

    Purpose Zoledronic acid (ZA) is being increasingly recognized for its anti-tumor properties, but the underlying functions are not well understood. In this study, we hypothesized that ZA inhibits ovarian cancer (OC) angiogenesis preventing Rac1 activation. Experimental Design The biological effects of ZA were examined using a series of in vitro (cell invasion, cytokine production, Rac1 activation, reverse-phase protein array and in vivo (orthotopic mouse models) experiments. Results There was significant inhibition of OC (HeyA8-MDR and OVCAR-5) cell invasion as well as reduced production of pro-angiogenic cytokines in response to ZA treatment. Furthermore, ZA inactivated Rac1 and decreased the levels of Pak1/p-38/matrix metalloproteinase-2 in OC cells. In vivo, ZA reduced tumor growth, angiogenesis and cell proliferation and inactivated Rac1 in both HeyA8-MDR and OVCAR-5 models. These in vivo antitumor effects were enhanced in both models when ZA was combined with nab-paclitaxel. Conclusion ZA has robust anti-tumor and anti-angiogenic activity and merits further clinical development as OC treatment. PMID:25595279

  20. 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... CONTRACT MANAGEMENT QUALITY ASSURANCE General 46.105 Contractor responsibilities. (a) The contractor is..., and furnishing such information to the Government as required. (b) The contractor may be required to...

  1. 41 CFR 60-250.44 - Required contents of affirmative action programs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... OPPORTUNITY, DEPARTMENT OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND...). (3) The contractor may use as a defense to an allegation of a violation of paragraph (c)(2) of this... the contractor's establishment; (ii) The Department of Veterans Affairs Regional Office nearest the...

  2. 41 CFR 60-250.44 - Required contents of affirmative action programs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... OPPORTUNITY, DEPARTMENT OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND...). (3) The contractor may use as a defense to an allegation of a violation of paragraph (c)(2) of this... the contractor's establishment; (ii) The Department of Veterans Affairs Regional Office nearest the...

  3. An activating mutant of Rac1 that fails to interact with Rho GDP-dissociation inhibitor stimulates membrane ruffling in mammalian cells.

    PubMed Central

    Gandhi, Payal N; Gibson, Richard M; Tong, Xiaofeng; Miyoshi, Jun; Takai, Yoshimi; Konieczkowski, Martha; Sedor, John R; Wilson-Delfosse, Amy L

    2004-01-01

    Rac1, a member of the Rho family of small GTP-binding proteins, is involved in the regulation of the actin cytoskeleton via activation of lamellipodia and membrane ruffle formation. RhoGDI (Rho-family-specific GDP-dissociation inhibitor) forms a complex with Rho proteins in the cytosol of mammalian cells. It not only regulates guanine nucleotide binding to Rho proteins, but may also function as a molecular shuttle to carry Rho proteins from an inactive cytosolic pool to the membrane for activation. These studies tested if RhoGDI is necessary for the translocation of Rac1 from the cytosol to the plasma membrane for the formation of membrane ruffles. We describe a novel mutant of Rac1, R66E (Arg66-->Glu), that fails to bind RhoGDI. This RhoGDI-binding-defective mutation is combined with a Rac1-activating mutation G12V, resulting in a double-mutant [Rac1(G12V/R66E)] that fails to interact with RhoGDI in COS-7 cells, but remains constitutively activated. This double mutant stimulates membrane ruffling to a similar extent as that observed after epidermal growth factor treatment of non-transfected cells. To confirm that Rac1 can signal ruffle formation in the absence of interaction with RhoGDI, Rac1(G12V) was overexpressed in cultured mesangial cells derived from a RhoGDI knockout mouse. Rac1-mediated membrane ruffling was indistinguishable between the RhoGDI(-/-) and RhoGDI(+/+) cell lines. In both the COS-7 and cultured mesangial cells, Rac1(G12V) and Rac1(G12V/R66E) co-localize with membrane ruffles. These findings suggest that interaction with RhoGDI is not essential in the mechanism by which Rac1 translocates to the plasma membrane to stimulate ruffle formation. PMID:14629200

  4. Rac-WAVE2 signaling is involved in the invasive and metastatic phenotypes of murine melanoma cells.

    PubMed

    Kurisu, Shusaku; Suetsugu, Shiro; Yamazaki, Daisuke; Yamaguchi, Hideki; Takenawa, Tadaomi

    2005-02-17

    WAVEs (WASP-family verprolin-homologous proteins) regulate the actin cytoskeleton through activation of Arp2/3 complex. As cell motility is regulated by actin cytoskeleton rearrangement and is required for tumor invasion and metastasis, blocking actin polymerization may be an effective strategy to prevent tumor dissemination. We show that WAVEs, especially WAVE2, are essential for invasion and metastasis of melanoma cells. Malignant B16F10 mouse melanoma cells expressed more WAVE1 and WAVE2 proteins and showed higher Rac activity than B16 parental cells, which are neither invasive nor metastatic. The effect of WAVE2 silencing by RNA interference (RNAi) on the highly invasive nature of B16F10 cells was more dramatic than that of WAVE1 RNAi. Membrane ruffling, cell motility, invasion into the extracellular matrix, and pulmonary metastasis of B16F10 cells were suppressed by WAVE2 RNAi. WAVE2 RNAi also had a profound effect on invasion induced by a constitutively active form of Rac (RacCA). In addition, ectopic expression of both RacCA and WAVE2 in B16 cells resulted in further increase in the invasiveness than that observed in B16 cells expressing only RacCA. Thus, WAVE2 acts as the primary effector downstream of Rac to achieve invasion and metastasis, suggesting that suppression of WAVE2 activity holds a promise for preventing cancer invasion and metastasis.

  5. 40 CFR 68.87 - Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Contractors. 68.87 Section 68.87... ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.87 Contractors. (a) Application. This section applies to contractors performing maintenance or repair, turnaround, major renovation, or...

  6. 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... INDIVIDUALS Maintenance of Records § 10.27 Government contractors. When the Department provides by a contract..., Criminal Penalties, any such contractor and any employee of the contractor are considered, in accordance...

  7. 49 CFR 199.245 - Contractor employees.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Contractor employees. 199.245 Section 199.245... Prevention Program § 199.245 Contractor employees. (a) With respect to those covered employees who are contractors or employed by a contractor, an operator may provide by contract that the alcohol testing...

  8. R-ketorolac Targets Cdc42 and Rac1 and Alters Ovarian Cancer Cell Behaviors Critical for Invasion and Metastasis

    PubMed Central

    Guo, Yuna; Kenney, Shelby Ray; Muller, Carolyn Y.; Adams, Sarah; Rutledge, Teresa; Romero, Elsa; Murray-Krezan, Cristina; Prekeris, Rytis; Sklar, Larry A.; Hudson, Laurie G.; Wandinger-Ness, Angela

    2015-01-01

    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 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 sum, we provide evidence for R-ketorolac as direct inhibitor of Cdc42 and Rac1 that is capable of modulating downstream GTPase-dependent, physiological 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. PMID:26206334

  9. 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. ©2015 American Association for Cancer Research.

  10. Deletion of epidermal Rac1 inhibits HPV-8 induced skin papilloma formation and facilitates HPV-8- and UV-light induced skin carcinogenesis

    PubMed Central

    Deshmukh, Jayesh; Pofahl, Ruth; Pfister, Herbert; Haase, Ingo

    2016-01-01

    Overexpression and increased activity of the small Rho GTPase Rac1 has been linked to squamous cell carcinoma of the epidermis and mucosa in humans. Targeted deletion of Rac1 or inhibition of Rac1 activity in epidermal keratinocytes reduced papilloma formation in a chemical skin carcinogenesis mouse model. However, a potential role of Rac1 in HPV- and UV-light induced skin carcinogenesis has not been investigated so far, solar UV radiation being an important carcinogen to the skin. To investigate this, we deleted Rac1 or modulated its activity in mice with transgenic expression of Human papilloma virus type-8 (HPV-8) in epidermal keratinocytes. Our data show that inhibition or deletion of Rac1 results in reduced papilloma formation upon UV-irradiation with a single dose, whereas constitutive activation of Rac1 strongly increases papilloma frequency in these mice. Surprisingly, we observed that, upon chronic UV-irradiation, the majority of mice with transgenic expression of HPV-8 and epidermis specific Rac1 deletion developed squamous cell carcinomas. Taken together, our data show that Rac1 exerts a dual role in skin carcinogenesis: its activation is, on one hand, required for HPV-8- and UV-light induced papilloma formation but, on the other, suppresses the development of squamous cell carcinomas. PMID:27506937

  11. Deletion of epidermal Rac1 inhibits HPV-8 induced skin papilloma formation and facilitates HPV-8- and UV-light induced skin carcinogenesis.

    PubMed

    Deshmukh, Jayesh; Pofahl, Ruth; Pfister, Herbert; Haase, Ingo

    2016-09-06

    Overexpression and increased activity of the small Rho GTPase Rac1 has been linked to squamous cell carcinoma of the epidermis and mucosa in humans. Targeted deletion of Rac1 or inhibition of Rac1 activity in epidermal keratinocytes reduced papilloma formation in a chemical skin carcinogenesis mouse model. However, a potential role of Rac1 in HPV- and UV-light induced skin carcinogenesis has not been investigated so far, solar UV radiation being an important carcinogen to the skin.To investigate this, we deleted Rac1 or modulated its activity in mice with transgenic expression of Human papilloma virus type-8 (HPV-8) in epidermal keratinocytes. Our data show that inhibition or deletion of Rac1 results in reduced papilloma formation upon UV-irradiation with a single dose, whereas constitutive activation of Rac1 strongly increases papilloma frequency in these mice. Surprisingly, we observed that, upon chronic UV-irradiation, the majority of mice with transgenic expression of HPV-8 and epidermis specific Rac1 deletion developed squamous cell carcinomas. Taken together, our data show that Rac1 exerts a dual role in skin carcinogenesis: its activation is, on one hand, required for HPV-8- and UV-light induced papilloma formation but, on the other, suppresses the development of squamous cell carcinomas.

  12. 41 CFR 60-300.44 - Required contents of affirmative action programs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... OPPORTUNITY, DEPARTMENT OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... contractor may use as a defense to an allegation of a violation of paragraph (c)(2) of this section that an... Representative in the local employment service office nearest the contractor's establishment; (ii) The Department...

  13. 41 CFR 60-300.44 - Required contents of affirmative action programs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... OPPORTUNITY, DEPARTMENT OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... contractor may use as a defense to an allegation of a violation of paragraph (c)(2) of this section that an... Representative in the local employment service office nearest the contractor's establishment; (ii) The Department...

  14. Medicare recovery audit contractors: what providers need to know and how to prepare.

    PubMed

    Riley, James B; Greis, Jason S

    2009-04-01

    RAC audits are on their way in 2009 and all providers should strive to be prepared. In a depressed economy in which most providers are experiencing decreased or stagnating reimbursement, an additional hit to the bottom line from a RAC audit is especially unwelcome. Providers have a number of tools at their disposal, however, to proactively prepare in advance of receiving a RAC demand letter or medical record request.

  15. 49 CFR 199.115 - Contractor employees.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Contractor employees. 199.115 Section 199.115... § 199.115 Contractor employees. With respect to those employees who are contractors or employed by a contractor, an operator may provide by contract that the drug testing, education, and training required by...

  16. 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 ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES General § 1726.27 Contractor's bonds. (a) RUS Form 168b, Contractor's Bond, shall be used when a contractor's bond is required by RUS Forms 200, 257...

  17. IbeA and OmpA of Escherichia coli K1 Exploit Rac1 Activation for Invasion of Human Brain Microvascular Endothelial Cells

    PubMed Central

    Maruvada, Ravi

    2012-01-01

    Meningitis-causing Escherichia coli K1 internalization of the blood-brain barrier is required for penetration into the brain, but the host-microbial interactions involved in E. coli entry of the blood-brain barrier remain incompletely understood. We show here that a meningitis-causing E. coli K1 strain RS218 activates Rac1 (GTP-Rac1) of human brain microvascular endothelial cells (HBMEC) in a time-dependent manner. Both activation and bacterial invasion were significantly inhibited in the presence of a Rac1 inhibitor. We further showed that the guanine nucleotide exchange factor Vav2, not β-Pix, was involved in E. coli K1-mediated Rac1 activation. Since activated STAT3 is known to bind GTP-Rac1, the relationship between STAT3 and Rac1 was examined in E. coli K1 invasion of HBMEC. Downregulation of STAT3 resulted in significantly decreased E. coli invasion compared to control HBMEC, as well as a corresponding decrease in GTP-Rac1, suggesting that Rac1 activation in response to E. coli is under the control of STAT3. More importantly, two E. coli determinants contributing to HBMEC invasion, IbeA and OmpA, were shown to affect both Rac1 activation and their association with STAT3. These findings demonstrate for the first time that specific E. coli determinants regulate a novel mechanism of STAT3 cross talk with Rac1 in E. coli K1 invasion of HBMEC. PMID:22451524

  18. IbeA and OmpA of Escherichia coli K1 exploit Rac1 activation for invasion of human brain microvascular endothelial cells.

    PubMed

    Maruvada, Ravi; Kim, Kwang Sik

    2012-06-01

    Meningitis-causing Escherichia coli K1 internalization of the blood-brain barrier is required for penetration into the brain, but the host-microbial interactions involved in E. coli entry of the blood-brain barrier remain incompletely understood. We show here that a meningitis-causing E. coli K1 strain RS218 activates Rac1 (GTP-Rac1) of human brain microvascular endothelial cells (HBMEC) in a time-dependent manner. Both activation and bacterial invasion were significantly inhibited in the presence of a Rac1 inhibitor. We further showed that the guanine nucleotide exchange factor Vav2, not β-Pix, was involved in E. coli K1-mediated Rac1 activation. Since activated STAT3 is known to bind GTP-Rac1, the relationship between STAT3 and Rac1 was examined in E. coli K1 invasion of HBMEC. Downregulation of STAT3 resulted in significantly decreased E. coli invasion compared to control HBMEC, as well as a corresponding decrease in GTP-Rac1, suggesting that Rac1 activation in response to E. coli is under the control of STAT3. More importantly, two E. coli determinants contributing to HBMEC invasion, IbeA and OmpA, were shown to affect both Rac1 activation and their association with STAT3. These findings demonstrate for the first time that specific E. coli determinants regulate a novel mechanism of STAT3 cross talk with Rac1 in E. coli K1 invasion of HBMEC.

  19. 48 CFR 47.207-5 - 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....207-5 Contractor responsibilities. Contractor responsibilities vary with the kinds of freight to be... furnished by the contractor. Otherwise, state that the contractor shall furnish clean and sound closed-type...

  20. 48 CFR 18.102 - Central contractor registration.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Central contractor... Central contractor registration. Contractors are not required to be registered in the Central Contractor.... (See 4.1102). However, contractors are required to register with CCR in order to gain access to the...

  1. 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 policy...

  2. 41 CFR 60-741.43 - Affirmative action policy.

    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 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 policy...

  3. Cyclic Mechanical Loading Is Essential for Rac1-Mediated Elongation and Remodeling of the Embryonic Mitral Valve.

    PubMed

    Gould, Russell A; Yalcin, Huseyin C; MacKay, Joanna L; Sauls, Kimberly; Norris, Russell; Kumar, Sanjay; Butcher, Jonathan T

    2016-01-11

    During valvulogenesis, globular endocardial cushions elongate and remodel into highly organized thin fibrous leaflets. Proper regulation of this dynamic process is essential to maintain unidirectional blood flow as the embryonic heart matures. In this study, we tested how mechanosensitive small GTPases, RhoA and Rac1, coordinate atrioventricular valve (AV) differentiation and morphogenesis. RhoA activity and its regulated GTPase-activating protein FilGAP are elevated during early cushion formation but decreased considerably during valve remodeling. In contrast, Rac1 activity was nearly absent in the early cushions but increased substantially as the valve matured. Using gain- and loss-of-function assays, we determined that the RhoA pathway was essential for the contractile myofibroblastic phenotype present in early cushion formation but was surprisingly insufficient to drive matrix compaction during valve maturation. The Rac1 pathway was necessary to induce matrix compaction in vitro through increased cell adhesion, elongation, and stress fiber alignment. Facilitating this process, we found that acute cyclic stretch was a potent activator of RhoA and subsequently downregulated Rac1 activity via FilGAP. On the other hand, chronic cyclic stretch reduced active RhoA and downstream FilGAP, which enabled Rac1 activation. Finally, we used partial atrial ligation experiments to confirm in vivo that altered cyclic mechanical loading augmented or restricted cushion elongation and thinning, directly through potentiation of active Rac1 and active RhoA, respectively. Together, these results demonstrate that cyclic mechanical signaling coordinates the RhoA to Rac1 signaling transition essential for proper embryonic mitral valve remodeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  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... contractors. When GAO provides by a contract for the operation by or on behalf of GAO of a system of personnel... of this part to be applied to such system. Any such contractor and any employee of such contractor...

  5. B1-control receive array coil (B-RAC) for reducing B1+ inhomogeneity in abdominal imaging at 3T-MRI

    NASA Astrophysics Data System (ADS)

    Kaneko, Yukio; Soutome, Yoshihisa; Habara, Hideta; Bito, Yoshitaka; Ochi, Hisaaki

    2018-02-01

    B1+ inhomogeneity in the human body increases as the nuclear magnetic resonance (NMR) frequency increases. Various methods have thus been developed to reduce B1+ inhomogeneity, such as a dielectric pad, a coupling coil, parallel transmit, and radio-frequency (RF) shimming. However, B1+ inhomogeneity still remains in some cases of abdominal imaging. In this study, we developed a B1-control receive array coil (B-RAC). Unlike the conventional receive array coil, B-RAC reduces B1+ inhomogeneity by using additional PIN diodes to generate the inductive loop during the RF transmit period. The inductive loop can generate dense and sparse regions of the magnetic flux, which can be used to compensate for B1+ inhomogeneity. First, B-RAC is modeled in the numerical simulation, and the spatial distributions of B1+ in a phantom and a human model were analyzed. Next, we fabricated a 12-channel B-RAC and measured receive sensitivity and B1+ maps in a 3T-MRI experiment. It was demonstrated that B-RAC can reduce B1+ inhomogeneity in the phantom and human model without increasing the maximum local specific absorption rate (SAR) in the body. B-RAC was also found to have almost the same the receive sensitivity as the conventional receive coil. Using RF shimming combined with B-RAC was revealed to more effectively reduce B1+ inhomogeneity than using only RF shimming. Therefore, B-RAC can reduce B1+ inhomogeneity while maintaining the receive sensitivity.

  6. 41 CFR 60-300.40 - Applicability of the affirmative action program requirement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... FEDERAL CONTRACTORS AND SUBCONTRACTORS REGARDING DISABLED VETERANS, RECENTLY SEPARATED VETERANS, ACTIVE... contractor also shall make the affirmative action program promptly available on-site upon OFCCP's request. ...

  7. 32 CFR 1701.16 - Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Contractors. 1701.16 Section 1701.16 National... Under the Privacy Act of 1974 § 1701.16 Contractors. (a) Any approved contract for the operation of a... prescribed by the Federal Acquisition Regulations (FAR) at 48 CFR part 24, requiring the contractor to comply...

  8. 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 affirmative...

  9. 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 construction...

  10. 41 CFR 60-300.43 - Affirmative action policy.

    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 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 affirmative...

  11. 41 CFR 60-250.43 - Affirmative action policy.

    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 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 affirmative...

  12. 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 construction...

  13. 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 affirmative...

  14. A role for POR1, a Rac1-interacting protein, in ARF6-mediated cytoskeletal rearrangements.

    PubMed Central

    D'Souza-Schorey, C; Boshans, R L; McDonough, M; Stahl, P D; Van Aelst, L

    1997-01-01

    The ARF6 GTPase, the least conserved member of the ADP ribosylation factor (ARF) family, associates with the plasma membrane and intracellular endosome vesicles. Mutants of ARF6 defective in GTP binding and hydrolysis have a marked effect on endocytic trafficking and the gross morphology of the peripheral membrane system. Here we report that expression of the GTPase-defective mutant of ARF6, ARF6(Q67L), remodels the actin cytoskeleton by inducing actin polymerization at the cell periphery. This cytoskeletal rearrangement was inhibited by co-expression of ARF6(Q67L) with deletion mutants of POR1, a Rac1-interacting protein involved in membrane ruffling, but not with the dominant-negative mutant of Rac1, Rac1(S17N). A synergistic effect between POR1 and ARF6 for the induction of actin polymerization was detected. Furthermore, we observed that ARF6 interacts directly with POR1 and that this interaction was GTP dependent. These findings indicate that ARF6 and Rac1 function on distinct signaling pathways to mediate cytoskeletal reorganization, and suggest a role for POR1 as an important regulatory element in orchestrating cytoskeletal rearrangements at the cell periphery induced by ARF6 and Rac1. PMID:9312003

  15. 75 FR 6669 - Federal Acquisition Regulation; Submission for OMB Review; Contractors' Purchasing Systems Reviews

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-10

    ...' Purchasing Systems Reviews AGENCIES: Department of Defense (DOD), General Services Administration (GSA), and National Aeronautics and Space Administration (NASA). ACTION: Notice of request for public comments... collection requirement concerning contractors' purchasing systems reviews. A request for public comments was...

  16. 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... Contractors 1845.502 Contractor responsibility. ...

  17. The regulation of vascular endothelial growth factor-induced microvascular permeability requires Rac and reactive oxygen species.

    PubMed

    Monaghan-Benson, Elizabeth; Burridge, Keith

    2009-09-18

    Vascular permeability is a complex process involving the coordinated regulation of multiple signaling pathways in the endothelial cell. It has long been documented that vascular endothelial growth factor (VEGF) greatly enhances microvascular permeability; however, the molecular mechanisms controlling VEGF-induced permeability remain unknown. Treatment of microvascular endothelial cells with VEGF led to an increase in reactive oxygen species (ROS) production. ROS are required for VEGF-induced permeability as treatment with the free radical scavenger, N-acetylcysteine, inhibited this effect. Additionally, treatment with VEGF caused ROS-dependent tyrosine phosphorylation of both vascular-endothelial (VE)-cadherin and beta-catenin. Rac1 was required for the VEGF-induced increase in permeability and adherens junction protein phosphorylation. Knockdown of Rac1 inhibited VEGF-induced ROS production consistent with Rac lying upstream of ROS in this pathway. Collectively, these data suggest that VEGF leads to a Rac-mediated generation of ROS, which, in turn, elevates the tyrosine phosphorylation of VE-cadherin and beta-catenin, ultimately regulating adherens junction integrity.

  18. Nuclear localization of coactivator RAC3 is mediated by a bipartite NLS and importin {alpha}3

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yeung, Percy Luk; Zhang, Aihua; Chen, J. Don

    2006-09-15

    The nuclear receptor coactivator RAC3 (also known as SRC-3/ACTR/AIB1/p/CIP/TRAM-1) belongs to the p160 coactivator family, which are involved in several physiological processes and diseases. Here we have investigated how RAC3 is translocated into the nucleus and show that it is mediated through a bipartite NLS and importin {alpha}3. This bipartite NLS is located within the conserved bHLH domain, and its mutation abolished nuclear localization. The NLS is also sufficient to cause nuclear import of EGFP, and the activity requires basic amino acids within the NLS. RAC3 binds strongly to importin {alpha}3, which also depends on the basic amino acids. Functionally,more » RAC3 cytoplasmic mutant loses its ability to enhance transcription, suggesting that nuclear localization is essential for coactivator function. Together, these results reveal a previous unknown mechanism for nuclear translocation of p160 coactivators and a critical function of the conserved bHLH within the coactivator.« less

  19. STEF/TIAM2-mediated Rac1 activity at the nuclear envelope regulates the perinuclear actin cap.

    PubMed

    Woroniuk, Anna; Porter, Andrew; White, Gavin; Newman, Daniel T; Diamantopoulou, Zoi; Waring, Thomas; Rooney, Claire; Strathdee, Douglas; Marston, Daniel J; Hahn, Klaus M; Sansom, Owen J; Zech, Tobias; Malliri, Angeliki

    2018-05-29

    The perinuclear actin cap is an important cytoskeletal structure that regulates nuclear morphology and re-orientation during front-rear polarisation. The mechanisms regulating the actin cap are currently poorly understood. Here, we demonstrate that STEF/TIAM2, a Rac1 selective guanine nucleotide exchange factor, localises at the nuclear envelope, co-localising with the key perinuclear proteins Nesprin-2G and Non-muscle myosin IIB (NMMIIB), where it regulates perinuclear Rac1 activity. We show that STEF depletion reduces apical perinuclear actin cables (a phenotype rescued by targeting active Rac1 to the nuclear envelope), increases nuclear height and impairs nuclear re-orientation. STEF down-regulation also reduces perinuclear pMLC and decreases myosin-generated tension at the nuclear envelope, suggesting that STEF-mediated Rac1 activity regulates NMMIIB activity to promote stabilisation of the perinuclear actin cap. Finally, STEF depletion decreases nuclear stiffness and reduces expression of TAZ-regulated genes, indicating an alteration in mechanosensing pathways as a consequence of disruption of the actin cap.

  20. Staphylococcus aureus keratinocyte invasion is mediated by integrin-linked kinase and Rac1.

    PubMed

    Sayedyahossein, Samar; Xu, Stacey X; Rudkouskaya, Alena; McGavin, Martin J; McCormick, John K; Dagnino, Lina

    2015-02-01

    Staphylococcus aureus is a major component of the skin microbiota and causes a large number of serious infections. S. aureus first interacts with epidermal keratinocytes to breach the epidermal barrier through mechanisms not fully understood. By use of primary keratinocytes from mice with epidermis-restricted Ilk gene inactivation and control integrin-linked kinase (ILK)-expressing littermates, we investigated the role of ILK in epidermal S. aureus invasion. Heat-killed, but not live, bacteria were internalized to Rab5- and Rab7-positive phagosomes, and incubation with keratinocyte growth factor increased their uptake 2.5-fold. ILK-deficient mouse keratinocytes internalized bacteria 2- to 4-fold less efficiently than normal cells. The reduced invasion by live S. aureus of ILK-deficient cells was restored in the presence of exogenous, constitutively active Rac1. Thus, Rac1 functions downstream from ILK during invasion. Further, invasion by S. aureus of Rac1-deficient cells was 2.5-fold lower than in normal cells. Paradoxically, staphylococcal cutaneous penetration of mouse skin explants with ILK-deficient epidermis was 35-fold higher than that of normal skin, indicating defects in epidermal barrier function in the absence of ILK. Thus, we identified an ILK-Rac1 pathway essential for bacterial invasion of keratinocytes, and established ILK as a key contributor to prevent invasive staphylococcal cutaneous infection. © FASEB.

  1. Blocking hepatic metastases of colon cancer cells using an shRNA against Rac1 delivered by activatable cell-penetrating peptide.

    PubMed

    Bao, Ying; Guo, Huihui; Lu, Yongliang; Feng, Wenming; Sun, Xinrong; Tang, Chengwu; Wang, Xiang; Shen, Mo

    2016-11-22

    Hepatic metastasis is one of the critical progressions of colon cancer. Blocking this process is key to prolonging survival time in cancer patients. Studies on activatable cell-penetrating peptides (dtACPPs) have demonstrated their potential as gene carriers. It showed high tumor cell-targeting specificity and transfection efficiency and low cytotoxicity in the in vitro settings of drug delivery. However, using this system to silence target genes to inhibit metastasis in colorectal cancer cells has not been widely reported and requires further investigation. In this study, we observed that expression of Rac1, a key molecule for cytoskeletal reorganization, was higher in hepatic metastatic tumor tissue compared with prime colon cancer tissue and that patients with high Rac1-expressing colon cancer showed shorter survival time. Base on these findings, we created dtACPP-PEG-DGL (dtACPPD)/shRac1 nanoparticles and demonstrated that they downregulated Rac1 expression in colon cancer cells. Moreover, we observed inhibitory effects on migration, invasion and adhesion in HCT116 colorectal cancer cells in vitro, and our results showed that Rac1 regulated colon cancer cell matrix adhesion through the regulation of cytofilament dynamics. Moreover, mechanically, repression of Rac1 inhibiting cells migration and invasion by enhancing cell to cell adhesion and reducing cell to extracellular matrix adhesion. Furthermore, when atCDPPD/shRac1 nanoparticles were administered intravenously to a HCT116 xenograft model, significant tumor metastasis to the liver was inhibited. Our results suggest that atCDPP/shRac1 nanoparticles may enable the blockade of hepatic metastasis in colon cancer.

  2. 48 CFR 3009.171-8 - Ineligible contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Ineligible contractors..., HOMELAND SECURITY ACQUISITION REGULATION (HSAR) ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Responsible Prospective Contractors 3009.171-8 Ineligible contractors. Any business concern determined to be ineligible...

  3. The Role of Rac1 on Carbachol-induced Contractile Activity in Detrusor Smooth Muscle from Streptozotocin-induced Diabetic Rats.

    PubMed

    Evcim, Atiye Sinem; Micili, Serap Cilaker; Karaman, Meral; Erbil, Guven; Guneli, Ensari; Gidener, Sedef; Gumustekin, Mukaddes

    2015-06-01

    This study was designed to determine the role of the small GTPase Rac1 on carbachol-induced contractile activity in detrusor smooth muscle using small inhibitor NSC 23766 in diabetic rats. Rac1 expression in bladder tissue was also evaluated. In the streptozotocin (STZ)-induced diabetic rat model, three study groups were composed of control, diabetic and insulin-treated diabetic subjects. The detrusor muscle strips were suspended in organ baths at the end of 8-12 weeks after STZ injection. Carbachol (CCh) (10(-9) -10(-4) M) concentration-response curves were obtained both in the absence and in the presence of Rac1 inhibitor NSC 23766 (0.1, 1 and 10 μM). Diabetes-related histopathological changes and Rac1 expressions were assessed by haematoxylin and eosin staining and immunohistochemical staining, respectively. CCh caused dose-dependent contractile responses in all the study groups. Rac1 inhibitor NSC 23766 inhibited CCh-induced contractile responses in all groups, but this inhibition seen in both diabetes groups was greater than in the control group. Histological examination revealed an increased bladder wall thickness both in the diabetes and in the insulin-treated diabetes groups compared to the control group. In immunohistochemical staining, expression of Rac1 was observed to be increased in all layers of bladder in both diabetic groups compared to the control group. In the diabetic bladders, increased expression of Rac1 and considerable inhibition of CCh-induced responses in the presence of NSC 23766 compared to those of the control group may indicate a specific role of Rac1 in diabetes-related bladder dysfunction, especially associated with cholinergic mediated detrusor overactivity. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  4. 48 CFR 1602.170-4 - Contractor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor. 1602.170-4 Section 1602.170-4 Federal Acquisition Regulations System OFFICE OF PERSONNEL MANAGEMENT FEDERAL EMPLOYEES... 1602.170-4 Contractor. Contractor means carrier. ...

  5. 48 CFR 1609.471 - Contractor certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor certification... EMPLOYEES HEALTH BENEFITS ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Debarment, Suspension, and Ineligibility 1609.471 Contractor certification. All FEHBP carriers and applicant carriers...

  6. 48 CFR 752.7013 - Contractor-mission relationships.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor-mission....7013 Contractor-mission relationships. For use in all USAID contracts involving performance overseas.... Contractor-Mission Relationships (OCT 1989) (a) The Contractor acknowledges that this contract is an...

  7. 48 CFR 852.237-70 - Contractor responsibilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor....237-70 Contractor responsibilities. As prescribed in 837.110, insert the following clause: Contractor Responsibilities (APR 1984) The contractor shall obtain all necessary licenses and/or permits required to perform...

  8. 30 CFR 45.4 - Independent contractor register.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Independent contractor register. 45.4 Section... ADMINISTRATIVE REQUIREMENTS INDEPENDENT CONTRACTORS § 45.4 Independent contractor register. (a) Each independent contractor shall provide the production-operator in writing the following information: (1) The independent...

  9. Distinctive and selective route of PI3K/PKCα-PKCδ/RhoA-Rac1 signaling in osteoclastic cell migration.

    PubMed

    Kim, Jin-Man; Kim, Mi Yeong; Lee, Kyunghee; Jeong, Daewon

    2016-12-05

    Cell migration during specialized stages of osteoclast precursors, mononuclear preosteoclasts, and multinucleated mature osteoclasts remain uncertain. M-CSF- and osteopontin-induced osteoclastic cell migration was inhibited by function-blocking monoclonal antibodies specific to the integrin αv and β3 subunits, suggesting that integrin αvβ3 mediates migratory signaling induced by M-CSF and osteopontin. M-CSF and osteopontin stimulation was shown to regulate two branched signaling processes, PI3K/PKCα/RhoA axis and PI3K/PKCδ/Rac1 axis. Interestingly, inactivation of RhoA or Rac1 blocked preosteoclast and mature osteoclast migration but not osteoclast precursor migration in a transwell-based cell migration assay. Moreover, the inhibitory effect on preosteoclast and mature osteoclast migration induced by Rac1 inactivation was more effective than that by RhoA inactivation. Collectively, our findings suggest that osteoclast precursor migration depends on PI3K/PKCα-PKCδ signaling mediated via integrin αvβ3 bypassing RhoA and Rac1, whereas preosteoclast and mature osteoclast migration relies on PI3K/PKCα-PKCδ/RhoA-Rac1 axis signaling mediated via integrin αvβ3 with increased dependency on PKCδ/Rac1 signaling route as differentiation progresses. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. 41 CFR 60-2.2 - Agency action.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Agency action. 60-2.2...-AFFIRMATIVE ACTION PROGRAMS General § 60-2.2 Agency action. (a) Any contractor required by § 60-2.1 to develop and maintain a written affirmative action program for each of its establishments that has not complied...

  11. WAVE2 deficiency reveals distinct roles in embryogenesis and Rac-mediated actin-based motility.

    PubMed

    Yan, Catherine; Martinez-Quiles, Narcisa; Eden, Sharon; Shibata, Tomoyuki; Takeshima, Fuminao; Shinkura, Reiko; Fujiwara, Yuko; Bronson, Roderick; Snapper, Scott B; Kirschner, Marc W; Geha, Raif; Rosen, Fred S; Alt, Frederick W

    2003-07-15

    The Wiskott-Aldrich syndrome related protein WAVE2 is implicated in the regulation of actin-cytoskeletal reorganization downstream of the small Rho GTPase, Rac. We inactivated the WAVE2 gene by gene-targeted mutation to examine its role in murine development and in actin assembly. WAVE2-deficient embryos survived until approximately embryonic day 12.5 and displayed growth retardation and certain morphological defects, including malformations of the ventricles in the developing brain. WAVE2-deficient embryonic stem cells displayed normal proliferation, whereas WAVE2-deficient embryonic fibroblasts exhibited severe growth defects, as well as defective cell motility in response to PDGF, lamellipodium formation and Rac-mediated actin polymerization. These results imply a non-redundant role for WAVE2 in murine embryogenesis and a critical role for WAVE2 in actin-based processes downstream of Rac that are essential for cell movement.

  12. Carbon-Ion Irradiation Suppresses Migration and Invasiveness of Human Pancreatic Carcinoma Cells MIAPaCa-2 via Rac1 and RhoA Degradation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fujita, Mayumi; Imadome, Kaori; Shoji, Yoshimi

    2015-09-01

    Purpose: To investigate the mechanisms underlying the inhibition of cancer cell migration and invasion by carbon (C)-ion irradiation. Methods and Materials: Human pancreatic cancer cells MIAPaCa-2, AsPC-1, and BxPC-3 were treated by x-ray (4 Gy) or C-ion (0.5, 1, 2, or 4 Gy) irradiation, and their migration and invasion were assessed 2 days later. The levels of guanosine triphosphate (GTP)-bound Rac1 and RhoA were determined by the active GTPase pull-down assay with or without a proteasome inhibitor, and the binding of E3 ubiquitin ligase to GTP-bound Rac1 was examined by immunoprecipitation. Results: Carbon-ion irradiation reduced the levels of GTP-bound Rac1 and RhoA, 2more » major regulators of cell motility, in MIAPaCa-2 cells and GTP-bound Rac1 in AsPC-1 and BxPC-3 cells. Proteasome inhibition reversed the effect, indicating that C-ion irradiation induced Rac1 and RhoA degradation via the ubiquitin (Ub)-proteasome pathway. E3 Ub ligase X-linked inhibitor of apoptosis protein (XIAP), which directly targets Rac1, was selectively induced in C-ion–irradiated MIAPaCa-2 cells and coprecipitated with GTP-bound Rac1 in C-ion–irradiated cells, which was associated with Rac1 ubiquitination. Cell migration and invasion reduced by C-ion radiation were restored by short interfering RNA–mediated XIAP knockdown, indicating that XIAP is involved in C-ion–induced inhibition of cell motility. Conclusion: In contrast to x-ray irradiation, C-ion treatment inhibited the activity of Rac1 and RhoA in MIAPaCa-2 cells and Rac1 in AsPC-1 and BxPC-3 cells via Ub-mediated proteasomal degradation, thereby blocking the motility of these pancreatic cancer cells.« less

  13. 48 CFR 1509.170-8 - Contractor Performance Report.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor Performance... AGENCY ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Contractor Performance Evaluations 1509.170-8 Contractor Performance Report. (a) Contractor Performance Reports (interim and final) must be prepared...

  14. 48 CFR 52.241-5 - Contractor's Facilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 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, unless...

  15. 14 CFR 1245.108 - License to contractor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false License to contractor. 1245.108 Section... INTELLECTUAL PROPERTY RIGHTS Patent Waiver Regulations § 1245.108 License to contractor. (a) Each contractor.... The license extends to the contractor's domestic subsidiaries and affiliates, if any, within the...

  16. 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 by...

  17. 48 CFR 33.207 - Contractor certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contractor certification... CONTRACTING REQUIREMENTS PROTESTS, DISPUTES, AND APPEALS Disputes and Appeals 33.207 Contractor certification. (a) Contractors shall provide the certification specified in paragraph (c) of this section when...

  18. 48 CFR 725.703 - Contractor employees.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor employees. 725... SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Source, Origin, and Nationality 725.703 Contractor employees. (a... on employees or consultants of either contractors or subcontractors providing services under an USAID...

  19. Different roles of the small GTPases Rac1, Cdc42, and RhoG in CALEB/NGC-induced dendritic tree complexity.

    PubMed

    Schulz, Jana; Franke, Kristin; Frick, Manfred; Schumacher, Stefan

    2016-10-01

    Rho GTPases play prominent roles in the regulation of cytoskeletal reorganization. Many aspects have been elaborated concerning the individual functions of Rho GTPases in distinct signaling pathways leading to cytoskeletal rearrangements. However, major questions have yet to be answered regarding the integration and the signaling hierarchy of different Rho GTPases in regulating the cytoskeleton in fundamental physiological events like neuronal process differentiation. Here, we investigate the roles of the small GTPases Rac1, Cdc42, and RhoG in defining dendritic tree complexity stimulated by the transmembrane epidermal growth factor family member CALEB/NGC. Combining gain-of-function and loss-of-function analysis in primary hippocampal neurons, we find that Rac1 is essential for CALEB/NGC-mediated dendritic branching. Cdc42 reduces the complexity of dendritic trees. Interestingly, we identify the palmitoylated isoform of Cdc42 to adversely affect dendritic outgrowth and dendritic branching, whereas the prenylated Cdc42 isoform does not. In contrast to Rac1, CALEB/NGC and Cdc42 are not directly interconnected in regulating dendritic tree complexity. Unlike Rac1, the Rac1-related GTPase RhoG reduces the complexity of dendritic trees by acting upstream of CALEB/NGC. Mechanistically, CALEB/NGC activates Rac1, and RhoG reduces the amount of CALEB/NGC that is located at the right site for Rac1 activation at the cell membrane. Thus, Rac1, Cdc42, and RhoG perform very specific and non-redundant functions at different levels of hierarchy in regulating dendritic tree complexity induced by CALEB/NGC. Rho GTPases play a prominent role in dendritic branching. CALEB/NGC is a transmembrane member of the epidermal growth factor (EGF) family that mediates dendritic branching, dependent on Rac1. CALEB/NGC stimulates Rac1 activity. RhoG inhibits CALEB/NGC-mediated dendritic branching by decreasing the amount of CALEB/NGC at the plasma membrane. Palmitoylated, but not prenylated form

  20. The Guanine Nucleotide Exchange Factor Tiam1 Affects Neuronal Morphology; Opposing Roles for the Small GTPases Rac and Rho

    PubMed Central

    van Leeuwen, Frank N.; Kain, Hendrie E.T.; van der Kammen, Rob A.; Michiels, Frits; Kranenburg, Onno W.; Collard, John G.

    1997-01-01

    The invasion-inducing T-lymphoma invasion and metastasis 1 (Tiam1) protein functions as a guanine nucleotide exchange factor (GEF) for the small GTPase Rac1. Differentiation-dependent expression of Tiam1 in the developing brain suggests a role for this GEF and its effector Rac1 in the control of neuronal morphology. Here we show that overexpression of Tiam1 induces cell spreading and affects neurite outgrowth in N1E-115 neuroblastoma cells. These effects are Rac-dependent and strongly promoted by laminin. Overexpression of Tiam1 recruits the α6β1 integrin, a laminin receptor, to specific adhesive contacts at the cell periphery, which are different from focal contacts. Cells overexpressing Tiam1 no longer respond to lysophosphatidic acid– induced neurite retraction and cell rounding, processes mediated by Rho, suggesting that Tiam1-induced activation of Rac antagonizes Rho signaling. This inhibition can be overcome by coexpression of constitutively active RhoA, which may indicate that regulation occurs at the level of Rho or upstream. Conversely, neurite formation induced by Tiam1 or Rac1 is further promoted by inactivating Rho. These results demonstrate that Rac- and Rho-mediated pathways oppose each other during neurite formation and that a balance between these pathways determines neuronal morphology. Furthermore, our data underscore the potential role of Tiam1 as a specific regulator of Rac during neurite formation and illustrate the importance of reciprocal interactions between the cytoskeleton and the extracellular matrix during this process. PMID:9348295

  1. Inhibition of prostate smooth muscle contraction and prostate stromal cell growth by the inhibitors of Rac, NSC23766 and EHT1864.

    PubMed

    Wang, Y; Kunit, T; Ciotkowska, A; Rutz, B; Schreiber, A; Strittmatter, F; Waidelich, R; Liu, C; Stief, C G; Gratzke, C; Hennenberg, M

    2015-06-01

    Medical therapy of lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) targets smooth muscle contraction in the prostate, or prostate growth. However, current therapeutic options are insufficient. Here, we investigated the role of Rac in the control of smooth muscle tone in human prostates and growth of prostate stromal cells. Experiments were performed using human prostate tissues from radical prostatectomy and cultured stromal cells (WPMY-1). Expression of Rac was examined by Western blot and fluorescence staining. Effects of Rac inhibitors (NSC23766 and EHT1864) on contractility were assessed in the organ bath. The effects of Rac inhibitors were assessed by pull-down, cytotoxicity using a cell counting kit, cytoskeletal organization by phalloidin staining and cell growth using an 5-ethynyl-2'-deoxyuridine assay. Expression of Rac1-3 was observed in prostate samples from each patient. Immunoreactivity for Rac1-3 was observed in the stroma, where it colocalized with the smooth muscle marker, calponin. NSC23766 and EHT1864 significantly reduced contractions of prostate strips induced by noradrenaline, phenylephrine or electrical field stimulation. NSC23766 and EHT1864 inhibited Rac activity in WPMY-1 cells. Survival of WPMY-1 cells ranged between 64 and 81% after incubation with NSC23766 (50 or 100 μM) or EHT1864 (25 μM) for 24 h. NSC23766 and EHT1864 induced cytoskeletal disorganization in WPMY-1 cells. Both inhibitors impaired the growth of WPMY-1 cells. Rac may be a link connecting the control of prostate smooth muscle tone with proliferation of smooth muscle cells. Improvements in LUTS suggestive of BPH by Rac inhibitors appears possible. © 2015 The British Pharmacological Society.

  2. 48 CFR 1845.502-70 - Contractor-acquired property.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor-acquired... Possession of Contractors 1845.502-70 Contractor-acquired property. All contractor-acquired property must be... contractor-acquired. (2) Submission of DD Form 1419, DOD Industrial Plant Requisition, or equivalent format...

  3. 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... Contractor testimony. As prescribed in (TAR) 48 CFR 1242.7000(b), insert the following clause: Contractor Testimony (OCT 1994) All requests for the testimony of the Contractor or its employees, and any intention to...

  4. Comparative Genomic Sequencing and Pathogenic Properties of Equine Herpesvirus 1 KyA and RacL11

    PubMed Central

    Shakya, Akhalesh K.; O’Callaghan, Dennis J.; Kim, Seong K.

    2017-01-01

    Equine herpesvirus 1 (EHV-1) is a major pathogen affecting equines worldwide. The virus causes respiratory disease, abortion, and, in some cases, neurological disease. EHV-1 Kentucky A (KyA) is attenuated in the mouse and equine, whereas wild-type pathogenic strain RacL11 induces severe inflammatory infiltration of the lung, causing infected mice to succumb. The complete DNA sequencing of the KyA genome revealed that genes UL17 (ORF17), US6 (ORF73; gI), US7 (ORF74; gE), and US8 (ORF75; 10 K) are deleted as compared to the RacL11 and Ab4 genomes. In-frame deletions in the US1 (ORF68), US4 (ORF71; gp2), and UL63 (ORF63; EICP0) genes and point mutations in 14 different open reading frames (ORFs) were detected in the KyA genome. Interestingly, UL1 (ORF1) and UL2 (ORF2) were deleted in both KyA and RacL11. Our previous studies showed that EHV-1 glycoproteins gI, gE, and full-length gp2 contribute to the pathogenesis of the RacL11 strain. The confirmation of these gene deletions in KyA suggests their contribution to the attenuation of this virus. The growth kinetics results revealed that KyA replicates to high titers in cell culture as compared to RacL11 and Ab4, indicating that the above genomic deletions and mutations in KyA do not have an inhibitory effect on KyA replication in cells of mouse, rabbit, equine, or human origin. Studies of EHV-1 pathogenesis in CBA mice showed that KyA is attenuated whereas mice infected with RacL11 succumbed by 3–6 days post-infection, which is consistent with our previous results. PMID:29312962

  5. 24 CFR 242.53 - Excluded contractors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Excluded contractors. 242.53... MORTGAGE INSURANCE FOR HOSPITALS Construction § 242.53 Excluded contractors. (a) Contracts relating to the... participation in federal programs, including but not limited to: A general contractor, a subcontractor, or...

  6. Open-RAC: Open-Design, Recirculating and Auto-Cleaning Zebrafish Maintenance System.

    PubMed

    Nema, Shubham; Bhargava, Yogesh

    2017-08-01

    Zebrafish is a vertebrate animal model. Their maintenance in large number under laboratory conditions is a daunting task. Commercially available recirculating zebrafish maintenance systems are used to efficiently handle the tasks of automatic sediment cleaning from zebrafish tanks with minimal waste of water. Due to their compact nature, they also ensure the maximal use of available lab space. However, the high costs of commercial systems present a limitation to researchers with limited funds. A cost-effective zebrafish maintenance system with major features offered by commercially available systems is highly desirable. Here, we describe a compact and recirculating zebrafish maintenance system. Our system is composed of cost-effective components, which are available in local markets and/or can be procured via online vendors. Depending on the expertise of end users, the system can be assembled in 2 days. The system is completely customizable as it offers geometry independent zebrafish tanks that are capable of auto-cleaning the sediments. Due to these features, we called our setup as Open-RAC (Open-design, Recirculating and Auto-Cleaning zebrafish maintenance system). Open-RAC is a cost-effective and viable alternative to the currently available zebrafish maintenance systems. Thus, we believe that the use of Open-RAC could promote the zebrafish research by removing the cost barrier for researchers.

  7. CRISPR-Cas-Mediated Gene Silencing Reveals RacR To Be a Negative Regulator of YdaS and YdaT Toxins in Escherichia coli K-12.

    PubMed

    Bindal, Gargi; Krishnamurthi, Revathy; Seshasayee, Aswin Sai Narain; Rath, Devashish

    2017-01-01

    Bacterial genomes are rich in horizontally acquired prophages. racR is an essential gene located in the rac prophage that is resident in many Escherichia coli genomes. Employing a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas-based gene silencing approach, we show that RacR is a negative regulator of the divergently transcribed and adjacent ydaS-ydaT operon in Escherichia coli K-12. Overexpression of YdaS and YdaT due to RacR depletion leads to cell division defects and decrease in survival. We further show that both YdaS and YdaT can act independently as toxins and that RacR serves to counteract the toxicity by tightly downregulating the expression of these toxins. IMPORTANCE racR is an essential gene and one of the many poorly studied genes found on the rac prophage element that is present in many Escherichia coli genomes. Employing a CRISPR-based approach, we have silenced racR expression to various levels and elucidated its physiological consequences. We show that the downregulation of racR leads to upregulation of the adjacent ydaS-ydaT operon. Both YdaS and YdaT act as toxins by perturbing the cell division resulting in enhanced cell killing. This work establishes a physiological role for RacR, which is to keep the toxic effects of YdaS and YdaT in check and promote cell survival. We, thus, provide a rationale for the essentiality of racR in Escherichia coli K-12 strains.

  8. CRISPR-Cas-Mediated Gene Silencing Reveals RacR To Be a Negative Regulator of YdaS and YdaT Toxins in Escherichia coli K-12

    PubMed Central

    Bindal, Gargi; Krishnamurthi, Revathy; Seshasayee, Aswin Sai Narain

    2017-01-01

    ABSTRACT Bacterial genomes are rich in horizontally acquired prophages. racR is an essential gene located in the rac prophage that is resident in many Escherichia coli genomes. Employing a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas-based gene silencing approach, we show that RacR is a negative regulator of the divergently transcribed and adjacent ydaS-ydaT operon in Escherichia coli K-12. Overexpression of YdaS and YdaT due to RacR depletion leads to cell division defects and decrease in survival. We further show that both YdaS and YdaT can act independently as toxins and that RacR serves to counteract the toxicity by tightly downregulating the expression of these toxins. IMPORTANCE racR is an essential gene and one of the many poorly studied genes found on the rac prophage element that is present in many Escherichia coli genomes. Employing a CRISPR-based approach, we have silenced racR expression to various levels and elucidated its physiological consequences. We show that the downregulation of racR leads to upregulation of the adjacent ydaS-ydaT operon. Both YdaS and YdaT act as toxins by perturbing the cell division resulting in enhanced cell killing. This work establishes a physiological role for RacR, which is to keep the toxic effects of YdaS and YdaT in check and promote cell survival. We, thus, provide a rationale for the essentiality of racR in Escherichia coli K-12 strains. PMID:29205229

  9. RAC1 GTP-ase signals Wnt-beta-catenin pathway mediated integrin-directed metastasis-associated tumor cell phenotypes in triple negative breast cancers.

    PubMed

    De, Pradip; Carlson, Jennifer H; Jepperson, Tyler; Willis, Scooter; Leyland-Jones, Brian; Dey, Nandini

    2017-01-10

    The acquisition of integrin-directed metastasis-associated (ID-MA) phenotypes by Triple-Negative Breast Cancer (TNBC) cells is caused by an upregulation of the Wnt-beta-catenin pathway (WP). We reported that WP is one of the salient genetic features of TNBC. RAC-GTPases, small G-proteins which transduce signals from cell surface proteins including integrins, have been implicated in tumorigenesis and metastasis by their role in essential cellular functions like motility. The collective percentage of alteration(s) in RAC1 in ER+ve BC was lower as compared to ER-ve BC (35% vs 57%) (brca/tcga/pub2015). High expression of RAC1 was associated with poor outcome for RFS with HR=1.48 [CI: 1.15-1.9] p=0.0019 in the Hungarian ER-veBC cohort. Here we examined how WP signals are transduced via RAC1 in the context of ID-MA phenotypes in TNBC. Using pharmacological agents (sulindac sulfide), genetic tools (beta-catenin siRNA), WP modulators (Wnt-C59, XAV939), RAC1 inhibitors (NSC23766, W56) and WP stimulations (LWnt3ACM, Wnt3A recombinant) in a panel of 6-7 TNBC cell lines, we studied fibronectin-directed (1) migration, (2) matrigel invasion, (3) RAC1 and Cdc42 activation, (4) actin dynamics (confocal microscopy) and (5) podia-parameters. An attenuation of WP, which (a) decreased cellular levels of beta-catenin, as well as its nuclear active-form, (b) decreased fibronectin-induced migration, (c) decreased invasion, (d) altered actin dynamics and (e) decreased podia-parameters was successful in blocking fibronectin-mediated RAC1/Cdc42 activity. Both Wnt-antagonists and RAC1 inhibitors blocked fibronectin-induced RAC1 activation and inhibited the fibronectin-induced ID-MA phenotypes following specific WP stimulation by LWnt3ACM as well as Wnt3A recombinant protein. To test a direct involvement of RAC1-activation in WP-mediated ID-MA phenotypes, we stimulated brain-metastasis specific MDA-MB231BR cells with LWnt3ACM. LWnt3ACM-stimulated fibronectin-directed migration was blocked by

  10. WAVE2 deficiency reveals distinct roles in embryogenesis and Rac-mediated actin-based motility

    PubMed Central

    Yan, Catherine; Martinez-Quiles, Narcisa; Eden, Sharon; Shibata, Tomoyuki; Takeshima, Fuminao; Shinkura, Reiko; Fujiwara, Yuko; Bronson, Roderick; Snapper, Scott B.; Kirschner, Marc W.; Geha, Raif; Rosen, Fred S.; Alt, Frederick W.

    2003-01-01

    The Wiskott–Aldrich syndrome related protein WAVE2 is implicated in the regulation of actin-cytoskeletal reorganization downstream of the small Rho GTPase, Rac. We inactivated the WAVE2 gene by gene-targeted mutation to examine its role in murine development and in actin assembly. WAVE2-deficient embryos survived until approximately embryonic day 12.5 and displayed growth retardation and certain morphological defects, including malformations of the ventricles in the developing brain. WAVE2-deficient embryonic stem cells displayed normal proliferation, whereas WAVE2-deficient embryonic fibroblasts exhibited severe growth defects, as well as defective cell motility in response to PDGF, lamellipodium formation and Rac-mediated actin polymerization. These results imply a non-redundant role for WAVE2 in murine embryogenesis and a critical role for WAVE2 in actin-based processes downstream of Rac that are essential for cell movement. PMID:12853475

  11. 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 system...

  12. 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 system...

  13. 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 system...

  14. 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 system...

  15. 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 system...

  16. 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... contractors. (a) No Bureau component may contract for the operation of a record system by or on behalf of the... component shall have the responsibility to ensure that the contractor complies with the contract...

  17. 41 CFR 60-250.41 - Availability of affirmative action program.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affirmative action program. 60-250.41 Section 60-250.41 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... OTHER PROTECTED VETERANS Affirmative Action Program § 60-250.41 Availability of affirmative action...

  18. 41 CFR 60-250.41 - Availability of affirmative action program.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affirmative action program. 60-250.41 Section 60-250.41 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... OTHER PROTECTED VETERANS Affirmative Action Program § 60-250.41 Availability of affirmative action...

  19. Periodic mechanical stress activates EGFR-dependent Rac1 mitogenic signals in rat nucleus pulpous cells via ERK1/2

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gao, Gongming; Shen, Nan; Jiang, Xuefeng

    2016-01-15

    The mitogenic effects of periodic mechanical stress on nucleus pulpous cells have been studied extensively but the mechanisms whereby nucleus pulpous cells sense and respond to mechanical stimulation remain a matter of debate. We explored this question by performing cell culture experiments in our self-developed periodic stress field and perfusion culture system. Under periodic mechanical stress, rat nucleus pulpous cell proliferation was significantly increased (p < 0.05 for each) and was associated with increases in the phosphorylation and activation of EGFR, Rac1, and ERK1/2 (p < 0.05 for each). Pretreatment with the ERK1/2 selective inhibitor PD98059 reduced periodic mechanical stress-induced nucleus pulpous cell proliferationmore » (p < 0.05 for each), while the activation levels of EGFR and Rac1 were not inhibited. Proliferation and phosphorylation of ERK1/2 were inhibited after pretreatment with the Rac1 inhibitor NSC23766 in nucleus pulpous cells in response to periodic mechanical stress (p < 0.05 for each), while the phosphorylation site of EGFR was not affected. Inhibition of EGFR activity with AG1478 abrogated nucleus pulpous cell proliferation (p < 0.05 for each) and attenuated Rac1 and ERK1/2 activation in nucleus pulpous cells subjected to periodic mechanical stress (p < 0.05 for each). These findings suggest that periodic mechanical stress promotes nucleus pulpous cell proliferation in part through the EGFR-Rac1-ERK1/2 signaling pathway, which links these three important signaling molecules into a mitogenic cascade. - Highlights: • The mechanism involved in nucleus pulpous cells to respond to mechanical stimuli. • Periodic mechanical stress can stimulate the phosphorylation of EGFR. • EGFR activates Rac1 and leads to rat nucleus pulpous cell proliferation. • EGFR and Rac1 activate ERK1/2 mitogenic signals in nucleus pulpous cells. • EGFR-Rac1-ERK1/2 is constitutes at least one critical signal transduction pathway.« less

  20. Vitreous-induced cytoskeletal rearrangements via the Rac1 GTPase-dependent signaling pathway in human retinal pigment epithelial cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Xionggao; Department of Ophthalmology, Hainan Medical College, Haikou; Wei, Yantao

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer Vitreous induces morphological changes and cytoskeletal rearrangements in RPE cells. Black-Right-Pointing-Pointer Rac1 is activated in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition prevents morphological changes in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition suppresses cytoskeletal rearrangements in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer The vitreous-induced effects are mediated by a Rac1 GTPase/LIMK1/cofilin pathway. -- Abstract: Proliferative vitreoretinopathy (PVR) is mainly caused by retinal pigment epithelial (RPE) cell migration, invasion, proliferation and transformation into fibroblast-like cells that produce the extracellular matrix (ECM). The vitreous humor is known to play an important role in PVR. An epithelial-to-mesenchymal transdifferentiation (EMT) of human RPE cells inducedmore » by 25% vitreous treatment has been linked to stimulation of the mesenchymal phenotype, migration and invasion. Here, we characterized the effects of the vitreous on the cell morphology and cytoskeleton in human RPE cells. The signaling pathway that mediates these effects was investigated. Serum-starved RPE cells were incubated with 25% vitreous, and the morphological changes were examined by phase-contrast microscopy. Filamentous actin (F-actin) was examined by immunofluorescence and confocal microscopy. Protein phosphorylation of AKT, ERK1/2, Smad2/3, LIM kinase (LIMK) 1 and cofilin was analyzed by Western blot analysis. Vitreous treatment induced cytoskeletal rearrangements, activated Rac1 and enhanced the phosphorylation of AKT, ERK1/2 and Smad2/3. When the cells were treated with a Rac activation-specific inhibitor, the cytoskeletal rearrangements were prevented, and the phosphorylation of Smad2/3 was blocked. Vitreous treatment also enhanced the phosphorylation of LIMK1 and cofilin and the Rac inhibitor blocked this effect. We propose that

  1. 45 CFR 5b.12 - Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Contractors. 5b.12 Section 5b.12 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION PRIVACY ACT REGULATIONS § 5b.12 Contractors. (a) All contracts entered into on or after September 27, 1975 which require a contractor to maintain...

  2. Management and operating contractors' pension plans

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    1987-06-01

    This report concerns the management of 28 M and O contractor pension plans with assets exceeding $2.6 billion in 1983. At the end of 1983, these pension plans were overfunded by $600 million. The Department could have saved $94 million in 1983 had the contractors been required to limit their pension plan contributions to the Government-established minimum level. Since 1979, the Department has continually reimbursed these contractors for contributions to pension plans that were already overfunded and we estimate that these plans are currently overfunded in excess of $1 billion. Additional annual savings of about $548,000 could be realized ifmore » the Department obtained waivers for M and O contractors participating in the Pension Benefit Guaranty Corporation's (PBGC) insurance program. Management and Administration, which has overall responsibility for controlling such costs, indicated it did not agree that contractors should fund pension plans at only the minimum required level. General agreement was indicated with the need to obtain waivers from PBGC premiums and better protect the Department's interest in contractor excess pension assets.« less

  3. 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. ...

  4. 41 CFR 60-300.41 - Availability of affirmative action program.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affirmative action program. 60-300.41 Section 60-300.41 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... FORCES SERVICE MEDAL VETERANS Affirmative Action Program § 60-300.41 Availability of affirmative action...

  5. 41 CFR 60-300.41 - Availability of affirmative action program.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affirmative action program. 60-300.41 Section 60-300.41 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... FORCES SERVICE MEDAL VETERANS Affirmative Action Program § 60-300.41 Availability of affirmative action...

  6. 34 CFR 5b.12 - Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Contractors. 5b.12 Section 5b.12 Education Office of the Secretary, Department of Education PRIVACY ACT REGULATIONS § 5b.12 Contractors. (a) All contracts entered into on or after September 27, 1975 which require a contractor to maintain or on behalf of the...

  7. Wave2 activates serum response element via its VCA region and functions downstream of Rac.

    PubMed

    Ishiguro, Kazuhiro; Cao, Zhifang; Ilasca, Marco Lopez; Ando, Takafumi; Xavier, Ramnik

    2004-12-10

    WAVE2 is a member of the WASP/WAVE family of protein effectors of actin reorganization and cell movement. In this report, we demonstrate that WAVE2 overexpression induces serum response element (SRE) activation through serum response factor. A WAVE2 mutant lacking the VCA region did not induce SRE activation and actin polymerization. WAVE2-induced SRE activation was blocked by exposure of cells to Latrunculin A, or overexpression of actin mutant R62D. The DeltaVCA mutant inhibited Rac V12-induced SRE activation, suggesting that WAVE2 lies downstream of Rac. Similar deletion of the VCA domain of WASP attenuated Cdc42 V12-mediated SRE activation, suggesting that WAVE2 acts in relation to Rac as WASP acts in relation to Cdc42. WAVE2 overexpression did not activate NF-kappaB.

  8. Novel insights into a retinoic-acid-induced cleft palate based on Rac1 regulation of the fibronectin arrangement.

    PubMed

    Tang, Qinghuang; Li, Liwen; Lee, Min-Jung; Ge, Qing; Lee, Jong-Min; Jung, Han-Sung

    2016-03-01

    Retinoic acid (RA)-induced cleft palate results from both extrinsic obstructions by the tongue and internal factors within the palatal shelves. Our previous study showed that the spatiotemporal expression of Rac1 regulates the fibronectin (FN) arrangement through cell density alterations that play an important role in palate development. In this study, we investigate the involvement of the Rac1 regulation of the FN arrangement in RA-induced cleft palate. Our results demonstrate that RA-induced intrinsic alterations in palatal shelves, including a delayed progress of cell condensation, delay palate development, even after the removal of the tongue. Further analysis shows that RA treatment diminishes the region-distinctive expression of Rac1 within the palatal shelves, which reversely alters the fibrillar arrangement of FN. Furthermore, RA treatment disrupts the formation of lamellipodia, which are indicative structures of cell migration that are regulated by Rac1. These results suggest that the Rac1 regulation of the FN arrangement is involved in RA-induced cleft palate through the regulation of cell migration, which delays the progress of cell condensation and subsequently influences the FN arrangement, inducing a delay in palate development. Our study provides new insights into the RA-induced impairment of palatal shelf elevation based on cell migration dynamics.

  9. Hydrostatic pressure promotes the proliferation and osteogenic/chondrogenic differentiation of mesenchymal stem cells: The roles of RhoA and Rac1.

    PubMed

    Zhao, Yin-Hua; Lv, Xin; Liu, Yan-Li; Zhao, Ying; Li, Qiang; Chen, Yong-Jin; Zhang, Min

    2015-05-01

    Our previous studies have shown that hydrostatic pressure can serve as an active regulator for bone marrow mesenchymal stem cells (BMSCs). The current work further investigates the roles of cytoskeletal regulatory proteins Ras homolog gene family member A (RhoA) and Ras-related C3 botulinum toxin substrate 1 (Rac1) in hydrostatic pressure-related effects on BMSCs. Flow cytometry assays showed that the hydrostatic pressure promoted cell cycle initiation in a RhoA- and Rac1-dependent manner. Furthermore, fluorescence assays confirmed that RhoA played a positive and Rac1 displayed a negative role in the hydrostatic pressure-induced F-actin stress fiber assembly. Western blots suggested that RhoA and Rac1 play central roles in the pressure-inhibited ERK phosphorylation, and Rac1 but not RhoA was involved in the pressure-promoted JNK phosphorylation. Finally, real-time polymerase chain reaction (PCR) experiments showed that pressure promoted the expression of osteogenic marker genes in BMSCs at an early stage of osteogenic differentiation through the up-regulation of RhoA activity. Additionally, the PCR results showed that pressure enhanced the expression of chondrogenic marker genes in BMSCs during chondrogenic differentiation via the up-regulation of Rac1 activity. Collectively, our results suggested that RhoA and Rac1 are critical to the pressure-induced proliferation and differentiation, the stress fiber assembly, and MAPK activation in BMSCs. Copyright © 2015. Published by Elsevier B.V.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Burdick, A.

    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, HVACmore » 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

  11. Ratiometric Imaging Using a Single Dye Enables Simultaneous Visualization of Rac1 and Cdc42 Activation.

    PubMed

    MacNevin, Christopher J; Toutchkine, Alexei; Marston, Daniel J; Hsu, Chia-Wen; Tsygankov, Denis; Li, Li; Liu, Bei; Qi, Timothy; Nguyen, Dan-Vinh; Hahn, Klaus M

    2016-03-02

    Biosensors that report endogenous protein activity in vivo can be based on environment-sensing fluorescent dyes. The dyes can be attached to reagents that bind selectively to a specific conformation of the targeted protein, such that binding leads to a fluorescence change. Dyes that are sufficiently bright for use at low, nonperturbing intracellular concentrations typically undergo changes in intensity rather than the shifts in excitation or emission maxima that would enable precise quantitation through ratiometric imaging. We report here mero199, an environment-sensing dye that undergoes a 33 nm solvent-dependent shift in excitation. The dye was used to generate a ratiometric biosensor of Cdc42 (CRIB199) without the need for additional fluorophores. CRIB199 was used in the same cell with a FRET sensor of Rac1 activation to simultaneously observe Cdc42 and Rac1 activity in cellular protrusions, indicating that Rac1 but not Cdc42 activity was reduced during tail retraction, and specific protrusions had reduced Cdc42 activity. A novel program (EdgeProps) used to correlate localized activation with cell edge dynamics indicated that Rac1 was specifically reduced during retraction.

  12. 48 CFR 51.104 - Furnishing assistance to contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contractors. 51.104 Section 51.104 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT USE OF GOVERNMENT SOURCES BY CONTRACTORS Contractor Use of Government Supply Sources 51.104 Furnishing assistance to contractors. After receiving an activity address code, the contracting...

  13. 48 CFR 52.246-1 - Contractor Inspection Requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Contractor Inspection....246-1 Contractor Inspection Requirements. As prescribed in 46.301, insert the following clause: Contractor Inspection Requirements (APR 1984) The Contractor is responsible for performing or having...

  14. Son of sevenless directly links the Robo receptor to rac activation to control axon repulsion at the midline.

    PubMed

    Yang, Long; Bashaw, Greg J

    2006-11-22

    Son of sevenless (Sos) is a dual specificity guanine nucleotide exchange factor (GEF) that regulates both Ras and Rho family GTPases and thus is uniquely poised to integrate signals that affect both gene expression and cytoskeletal reorganization. Here, using genetics, biochemistry, and cell biology, we demonstrate that Sos is recruited to the plasma membrane, where it forms a ternary complex with the Roundabout receptor and the SH3-SH2 adaptor protein Dreadlocks (Dock) to regulate Rac-dependent cytoskeletal rearrangement in response to the Slit ligand. Intriguingly, the Ras and Rac-GEF activities of Sos can be uncoupled during Robo-mediated axon repulsion; Sos axon guidance function depends on its Rac-GEF activity, but not its Ras-GEF activity. These results provide in vivo evidence that the Ras and RhoGEF domains of Sos are separable signaling modules and support a model in which Robo recruits Sos to the membrane via Dock to activate Rac during midline repulsion.

  15. Desmoglein 3 acting as an upstream regulator of Rho GTPases, Rac-1/Cdc42 in the regulation of actin organisation and dynamics

    PubMed Central

    Man Tsang, Siu; Brown, Louise; Gadmor, Hanan; Gammon, Luke; Fortune, Farida; Wheeler, Ann; Wan, Hong

    2012-01-01

    Desmoglein 3 (Dsg3), a member of the desmoglein sub-family, serves as an adhesion molecule in desmosomes. Our previous study showed that overexpression of human Dsg3 in several epithelial lines induces formation of membrane protrusions, a phenotype suggestive of Rho GTPase activation. Here we examined the interaction between Dsg3 and actin in detail and showed that endogenous Dsg3 colocalises and interacts with actin, particularly the junctional actin in a Rac1-dependent manner. Ablation of Rac1 activity by dominant negative Rac1 mutant (N17Rac1) or the Rac1 specific inhibitor (NSC23766) directly disrupts the interaction between Dsg3 and actin. Assembly of the junctional actin at the cell borders is accompanied with enhanced levels of Dsg3, while inhibition of Dsg3 by RNAi results in profound changes in the organisation of actin cytoskeleton. In accordance, overexpression of Dsg3 results in a remarkable increase of Rac1 and Cdc42 activities and to a lesser extent, RhoA. The enhancements in Rho GTPases are accompanied by the pronounced actin-based membrane structures such as lamellipodia and filopodia, enhanced rate of actin turnover and cell polarisation. Together, our results reveal an important novel function for Dsg3 in promoting actin dynamics through regulating Rac1 and Cdc42 activation in epithelial cells. PMID:22796473

  16. 41 CFR 60-741.44 - Required contents of affirmative action programs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... OPPORTUNITY, DEPARTMENT OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF FEDERAL... the requirements of this paragraph (c). (3) The contractor may use as a defense to an allegation of a...) The Department of Veterans Affairs Regional Office nearest the contractor's establishment (www.va.gov...

  17. Ofloxacin induces apoptosis via β1 integrin-EGFR-Rac1-Nox2 pathway in microencapsulated chondrocytes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sheng, Zhi-Guo; Huang, Wei; Liu, Yu-Xiang

    2013-02-15

    Quinolones (QNs)-induced arthropathy is an important toxic side-effect in immature animals leading to the restriction of their therapeutic use in pediatrics. Ofloxacin, a typical QN, was found to induce the chondrocytes apoptosis in the early phase (12–48 h) of arthropathy in our previous study. However, the exact mechanism(s) is unclear. Microencapsulated juvenile rabbit joint chondrocytes, a three-dimensional culture system, is utilized to perform the present study. Ofloxacin, at a therapeutically relevant concentration (10 μg/ml), disturbs the interaction between β1 integrin and activated intracellular signaling proteins at 12 h, which is inhibited when supplementing Mg{sup 2+}. Intracellular reactive oxygen species (ROS)more » significantly increases in a time-dependent manner after exposure to ofloxacin for 12–48 h. Furthermore, ofloxacin markedly enhances the level of activated Rac1 and epidermal growth factor receptor (EGFR) phosphorylation, and its inhibition in turn reduces the ROS production, apoptosis and Rac1 activation. Silencing Nox2, Rac1 or supplementing Mg{sup 2+} inhibits ROS accumulation, apoptosis occurrence and EGFR phosphorylation induced by ofloxacin. However, depletion of Nox2, Rac1 and inhibition of EGFR do not affect ofloxacin-mediated loss of interaction between β1 integrin and activated intracellular signaling proteins. In addition, ofloxacin also induces Vav2 phosphorylation, which is markedly suppressed after inactivating EGFR or supplementing Mg{sup 2+}. These results suggest that ofloxacin causes Nox2-mediated intracellular ROS production by disrupting the β1 integrin function and then activating the EGFR-Vav2-Rac1 pathway, finally resulting in apoptosis within 12–48 h exposure. The present study provides a novel insight regarding the potential role of Nox-driven ROS in QNs-induced arthropathy. - Highlights: ► Ofloxacin induces Nox2-driven ROS in encapsulated chondrocyte at 12–48 h. ► Ofloxacin stimulates ROS

  18. 30 CFR 45.3 - Identification of independent contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Identification of independent contractors. 45.3... ADMINISTRATIVE REQUIREMENTS INDEPENDENT CONTRACTORS § 45.3 Identification of independent contractors. (a) Any independent contractor may obtain a permanent MSHA identification number. To obtain an identification number...

  19. 48 CFR 52.204-7 - Central Contractor Registration.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Central Contractor....204-7 Central Contractor Registration. As prescribed in 4.1105, use the following clause: Central Contractor Registration (APR 2008) (a) Definitions. As used in this clause— Central Contractor Registration...

  20. 48 CFR 970.5244-1 - 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... for Management and Operating Contracts 970.5244-1 Contractor purchasing system. As prescribed in 970.4403 insert the following clause: Contractor Purchasing System (AUG 2009) (a) General. The Contractor...

  1. 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).

  2. 48 CFR 242.7000 - Contractor business system deficiencies.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 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 subpart— Acceptable contractor business systems and contractor business systems are defined in the clause at 252.242...

  3. 48 CFR 242.7000 - Contractor business system deficiencies.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 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 subpart— Acceptable contractor business systems and contractor business systems are defined in the clause at 252.242...

  4. 48 CFR 242.7000 - Contractor business system deficiencies.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 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 subpart— Acceptable contractor business systems and contractor business systems are defined in the clause at 252.242...

  5. 48 CFR 242.7000 - Contractor business system deficiencies.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 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 subpart— Acceptable contractor business systems and contractor business systems are defined in the clause at 252.242...

  6. 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 that...

  7. 48 CFR 1552.237-76 - Government-Contractor Relations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 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 that...

  8. 48 CFR 1552.237-76 - Government-Contractor Relations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true 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 that...

  9. 48 CFR 42.402 - Visits to contractors' facilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Visits to contractors... contractors' facilities. (a) Government personnel planning to visit a contractor's facility in connection with... positions, and security clearances. (2) Date and duration of visit. (3) Name and address of contractor and...

  10. Rac1 and Cdc42 Differentially Modulate Cigarette Smoke–Induced Airway Cell Migration through p120-Catenin–Dependent and –Independent Pathways

    PubMed Central

    Zhang, Lili; Gallup, Marianne; Zlock, Lorna; Finkbeiner, Walter E.; McNamara, Nancy A.

    2014-01-01

    The adherens junction protein p120-catenin (p120ctn) shuttles between E-cadherin–bound and cytoplasmic pools to regulate E-cadherin/catenin complex stability and cell migration, respectively. When released from the adherens junction, p120ctn promotes cell migration through modulation of the Rho GTPases Rac1, Cdc42, and RhoA. Accordingly, the down-regulation and cytoplasmic mislocalization of p120ctn has been reported in all subtypes of lung cancers and is associated with grave prognosis. Previously, we reported that cigarette smoke induced cytoplasmic translocation of p120ctn and cell migration, but the underlying mechanism was unclear. Using primary human bronchial epithelial cells exposed to smoke-concentrated medium (Smk), we observed the translocation of Rac1 and Cdc42, but not RhoA, to the leading edge of polarized and migrating human bronchial epithelial cells. Rac1 and Cdc42 were robustly activated by smoke, whereas RhoA was inhibited. Accordingly, siRNA knockdown of Rac1 or Cdc42 completely abolished Smk-induced cell migration, whereas knockdown of RhoA had no effect. p120ctn/Rac1 double knockdown completely abolished Smk-induced cell migration, whereas p120ctn/Cdc42 double knockdown did not. These data suggested that Rac1 and Cdc42 coactivation was essential to smoke-promoted cell migration in the presence of p120ctn, whereas migration proceeded via Rac1 alone in the absence of p120ctn. Thus, Rac1 may provide an omnipotent therapeutic target in reversing cell migration during the early (intact p120ctn) and late (loss of p120ctn) stages of lung carcinogenesis. PMID:23562274

  11. 41 CFR 109-38.301-1 - Contractors' use.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Contractors' use. 109-38...-38.301-1 Contractors' use. Heads of field organizations shall ensure that provisions of the FPMR concerning contractor use of Government motor vehicles are complied with by their designated contractors. ...

  12. 48 CFR 47.207-5 - Contractor responsibilities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....207-5 Contractor responsibilities. Contractor responsibilities vary with the kinds of freight to be shipped and services required. The contracting officer shall specify clearly those service requirements... freight. The contracting officer shall insert the clause at 52.247-16, Contractor Responsibility for...

  13. 48 CFR 47.207-5 - Contractor responsibilities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....207-5 Contractor responsibilities. Contractor responsibilities vary with the kinds of freight to be shipped and services required. The contracting officer shall specify clearly those service requirements... freight. The contracting officer shall insert the clause at 52.247-16, Contractor Responsibility for...

  14. 48 CFR 47.207-5 - Contractor responsibilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ....207-5 Contractor responsibilities. Contractor responsibilities vary with the kinds of freight to be shipped and services required. The contracting officer shall specify clearly those service requirements... freight. The contracting officer shall insert the clause at 52.247-16, Contractor Responsibility for...

  15. 48 CFR 47.207-5 - Contractor responsibilities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ....207-5 Contractor responsibilities. Contractor responsibilities vary with the kinds of freight to be shipped and services required. The contracting officer shall specify clearly those service requirements... freight. The contracting officer shall insert the clause at 52.247-16, Contractor Responsibility for...

  16. 78 FR 11164 - Policy on Contractor Profits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-15

    ... DEPARTMENT OF DEFENSE Defense Acquisition Regulations System Policy on Contractor Profits AGENCY... Authorization Act for Fiscal Year 2013. Section 804, Department of Defense Policy on Contractor Profits... modifications to such guidelines that are necessary to ensure an appropriate link between contractor profit and...

  17. 48 CFR 970.5203-3 - Contractor's organization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor's organization... for Management and Operating Contracts 970.5203-3 Contractor's organization. As prescribed in 970.0371-9, insert the following clause: Contractor's Organization (DEC 2000) (a) Organization chart. As...

  18. 48 CFR 46.301 - Contractor inspection requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contractor inspection... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.301 Contractor inspection requirements. The contracting officer shall insert the clause at 52.246-1, Contractor Inspection Requirements, in solicitations...

  19. 41 CFR 60-741.41 - Availability of affirmative action program.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affirmative action program. 60-741.41 Section 60-741.41 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS REGARDING INDIVIDUALS WITH DISABILITIES Affirmative Action Program § 60-741.41 Availability of...

  20. 41 CFR 60-741.41 - Availability of affirmative action program.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affirmative action program. 60-741.41 Section 60-741.41 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS REGARDING INDIVIDUALS WITH DISABILITIES Affirmative Action Program § 60-741.41 Availability of...

  1. 48 CFR 923.102 - Applicability to contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contractors. 923.102 Section 923.102 Federal Acquisition Regulations System DEPARTMENT OF ENERGY SOCIOECONOMIC... 923.102 Applicability to contractors. Many of the Department's major facilities are operated by contractors. Provisions regarding those contracts may be found at Part 970 of this chapter. At other locations...

  2. 41 CFR 60-250.44 - Required contents of affirmative action programs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affirmative action programs. 60-250.44 Section 60-250.44 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 250-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... OTHER PROTECTED VETERANS Affirmative Action Program § 60-250.44 Required contents of affirmative action...

  3. 48 CFR 2427.305-2 - Follow-up by contractor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Follow-up by contractor....305-2 Follow-up by contractor. (b) Contractor reports. Contractors shall complete and submit to the... Contracting Officer shall send the form to those contractors whose contract work may have required the...

  4. Deficiency of Rac1 Blocks NADPH Oxidase Activation, Inhibits Endoplasmic Reticulum Stress, and Reduces Myocardial Remodeling in a Mouse Model of Type 1 Diabetes

    PubMed Central

    Li, Jianmin; Zhu, Huaqing; Shen, E; Wan, Li; Arnold, J. Malcolm O.; Peng, Tianqing

    2010-01-01

    OBJECTIVE Our recent study demonstrated that Rac1 and NADPH oxidase activation contributes to cardiomyocyte apoptosis in short-term diabetes. This study was undertaken to investigate if disruption of Rac1 and inhibition of NADPH oxidase would prevent myocardial remodeling in chronic diabetes. RESEARCH DESIGN AND METHODS Diabetes was induced by injection of streptozotocin in mice with cardiomyocyte-specific Rac1 knockout and their wild-type littermates. In a separate experiment, wild-type diabetic mice were treated with vehicle or apocynin in drinking water. Myocardial hypertrophy, fibrosis, endoplasmic reticulum (ER) stress, inflammatory response, and myocardial function were investigated after 2 months of diabetes. Isolated adult rat cardiomyocytes were cultured and stimulated with high glucose. RESULTS In diabetic hearts, NADPH oxidase activation, its subunits' expression, and reactive oxygen species production were inhibited by Rac1 knockout or apocynin treatment. Myocardial collagen deposition and cardiomyocyte cross-sectional areas were significantly increased in diabetic mice, which were accompanied by elevated expression of pro-fibrotic genes and hypertrophic genes. Deficiency of Rac1 or apocynin administration reduced myocardial fibrosis and hypertrophy, resulting in improved myocardial function. These effects were associated with a normalization of ER stress markers' expression and inflammatory response in diabetic hearts. In cultured cardiomyocytes, high glucose–induced ER stress was inhibited by blocking Rac1 or NADPH oxidase. CONCLUSIONS Rac1 via NADPH oxidase activation induces myocardial remodeling and dysfunction in diabetic mice. The role of Rac1 signaling may be associated with ER stress and inflammation. Thus, targeting inhibition of Rac1 and NADPH oxidase may be a therapeutic approach for diabetic cardiomyopathy. PMID:20522592

  5. 14 CFR 1245.108 - License to contractor.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true License to contractor. 1245.108 Section 1245.108 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PATENTS AND OTHER INTELLECTUAL PROPERTY RIGHTS Patent Waiver Regulations § 1245.108 License to contractor. (a) Each contractor reporting...

  6. 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, the...

  7. 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, the...

  8. 32 CFR 989.23 - Contractor prepared documents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Contractor prepared documents. 989.23 Section... PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.23 Contractor prepared documents. All Air Force... should reflect on the cover sheet they are an Air Force document. Contractor preparation information...

  9. 6 CFR 25.8 - Government contractor Defense.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 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, the...

  10. 40 CFR 68.87 - Contractors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.87 Contractors. (a) Application. This... known potential fire, explosion, or toxic release hazards related to the contractor's work and the... instructed in the known potential fire, explosion, or toxic release hazards related to his/her job and the...

  11. 40 CFR 68.87 - Contractors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.87 Contractors. (a) Application. This... known potential fire, explosion, or toxic release hazards related to the contractor's work and the... instructed in the known potential fire, explosion, or toxic release hazards related to his/her job and the...

  12. 40 CFR 68.87 - Contractors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.87 Contractors. (a) Application. This... known potential fire, explosion, or toxic release hazards related to the contractor's work and the... instructed in the known potential fire, explosion, or toxic release hazards related to his/her job and the...

  13. 40 CFR 68.87 - Contractors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.87 Contractors. (a) Application. This... known potential fire, explosion, or toxic release hazards related to the contractor's work and the... instructed in the known potential fire, explosion, or toxic release hazards related to his/her job and the...

  14. Cirmtuzumab inhibits Wnt5a-induced Rac1 activation in chronic lymphocytic leukemia treated with ibrutinib

    PubMed Central

    Yu, J; Chen, L; Cui, B; Wu, Christina; Choi, M Y; Chen, Y; Zhang, L; Rassenti, L Z; Widhopf II, G F; Kipps, T J

    2017-01-01

    Signaling via the B cell receptor (BCR) plays an important role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). This is underscored by the clinical effectiveness of ibrutinib, an inhibitor of Bruton's tyrosine kinase (BTK) that can block BCR-signaling. However, ibrutinib cannot induce complete responses (CR) or durable remissions without continued therapy, suggesting alternative pathways also contribute to CLL growth/survival that are independent of BCR-signaling. ROR1 is a receptor for Wnt5a, which can promote activation of Rac1 to enhance CLL-cell proliferation and survival. In this study, we found that CLL cells of patients treated with ibrutinib had activated Rac1. Moreover, Wnt5a could induce Rac1 activation and enhance proliferation of CLL cells treated with ibrutinib at concentrations that were effective in completely inhibiting BTK and BCR-signaling. Wnt5a-induced Rac1 activation could be blocked by cirmtuzumab (UC-961), an anti-ROR1 mAb. We found that treatment with cirmtuzumab and ibrutinib was significantly more effective than treatment with either agent alone in clearing leukemia cells in vivo. This study indicates that cirmtuzumab may enhance the activity of ibrutinib in the treatment of patients with CLL or other ROR1+ B-cell malignancies. PMID:27904138

  15. Cirmtuzumab inhibits Wnt5a-induced Rac1 activation in chronic lymphocytic leukemia treated with ibrutinib.

    PubMed

    Yu, J; Chen, L; Cui, B; Wu, Christina; Choi, M Y; Chen, Y; Zhang, L; Rassenti, L Z; Widhopf Ii, G F; Kipps, T J

    2017-06-01

    Signaling via the B cell receptor (BCR) plays an important role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). This is underscored by the clinical effectiveness of ibrutinib, an inhibitor of Bruton's tyrosine kinase (BTK) that can block BCR-signaling. However, ibrutinib cannot induce complete responses (CR) or durable remissions without continued therapy, suggesting alternative pathways also contribute to CLL growth/survival that are independent of BCR-signaling. ROR1 is a receptor for Wnt5a, which can promote activation of Rac1 to enhance CLL-cell proliferation and survival. In this study, we found that CLL cells of patients treated with ibrutinib had activated Rac1. Moreover, Wnt5a could induce Rac1 activation and enhance proliferation of CLL cells treated with ibrutinib at concentrations that were effective in completely inhibiting BTK and BCR-signaling. Wnt5a-induced Rac1 activation could be blocked by cirmtuzumab (UC-961), an anti-ROR1 mAb. We found that treatment with cirmtuzumab and ibrutinib was significantly more effective than treatment with either agent alone in clearing leukemia cells in vivo. This study indicates that cirmtuzumab may enhance the activity of ibrutinib in the treatment of patients with CLL or other ROR1 + B-cell malignancies.

  16. 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.

  17. Upregulation of S1P1 and Rac1 receptors in the pulmonary vasculature of nitrofen-induced congenital diaphragmatic hernia.

    PubMed

    Zimmer, Julia; Takahashi, Toshiaki; Duess, Johannes W; Hofmann, Alejandro D; Puri, Prem

    2016-02-01

    Sphingolipids play a crucial role in pulmonary development. The sphingosine kinase 1 (SphK1) modulates the synthesis of sphingolipid sphingosine-1-phosphate (S1P). S1P regulates cell proliferation and angiogenesis via different receptors, S1P1, S1P2 and S1P3, which all influence the expression of Ras-related C3 botulinum toxin substrate 1 (Rac1). We designed this study to test the hypothesis that the S1P/Rac1 pathway is altered in the nitrofen-induced CDH model. Pregnant rats received nitrofen or vehicle on D9. On D21, fetuses were killed and divided into nitrofen and control group (n = 12). QRT-PCR, western blotting and confocal-immunofluorescence microscopy were performed to reveal pulmonary gene and protein expression levels of SphK1, S1P1, S1P2, S1P3 and Rac1. Pulmonary gene expression of S1P1 and Rac1 was significantly increased in the CDH group compared to controls, whereas S1P2 and S1P3 expression was decreased. These results were confirmed by western blotting and confocal microscopy. SphK1 expression was not found to be altered. The increased expression of S1P1 and Rac1 in the pulmonary vasculature of nitrofen-induced CDH lungs suggests that S1P1 and Rac1 are important mediators of PH in this model.

  18. Slit stimulation recruits Dock and Pak to the roundabout receptor and increases Rac activity to regulate axon repulsion at the CNS midline.

    PubMed

    Fan, Xueping; Labrador, Juan Pablo; Hing, Huey; Bashaw, Greg J

    2003-09-25

    Drosophila Roundabout (Robo) is the founding member of a conserved family of repulsive axon guidance receptors that respond to secreted Slit proteins. Here we present evidence that the SH3-SH2 adaptor protein Dreadlocks (Dock), the p21-activated serine-threonine kinase (Pak), and the Rac1/Rac2/Mtl small GTPases can function during Robo repulsion. Loss-of-function and genetic interaction experiments suggest that limiting the function of Dock, Pak, or Rac partially disrupts Robo repulsion. In addition, Dock can directly bind to Robo's cytoplasmic domain, and the association of Dock and Robo is enhanced by stimulation with Slit. Furthermore, Slit stimulation can recruit a complex of Dock and Pak to the Robo receptor and trigger an increase in Rac1 activity. These results provide a direct physical link between the Robo receptor and an important cytoskeletal regulatory protein complex and suggest that Rac can function in both attractive and repulsive axon guidance.

  19. Sonic hedgehog signaling regulates actin cytoskeleton via Tiam1-Rac1 cascade during spine formation.

    PubMed

    Sasaki, Nobunari; Kurisu, Junko; Kengaku, Mineko

    2010-12-01

    The sonic hedgehog (Shh) pathway has essential roles in several processes during development of the vertebrate central nervous system (CNS). Here, we report that Shh regulates dendritic spine formation in hippocampal pyramidal neurons via a novel pathway that directly regulates the actin cytoskeleton. Shh signaling molecules Patched (Ptc) and Smoothened (Smo) are expressed in several types of postmitotic neurons, including cerebellar Purkinje cells and hippocampal pyramidal neurons. Knockdown of Smo induces dendritic spine formation in cultured hippocampal neurons independently of Gli-mediated transcriptional activity. Smo interacts with Tiam1, a guanine nucleotide exchange factor for Rac1, via its cytoplasmic C-terminal region. Inhibition of Tiam1 or Rac1 activity suppresses spine induction by Smo knockdown. Shh induces remodeling of the actin cytoskeleton independently of transcriptional activation in mouse embryonic fibroblasts. These findings demonstrate a novel Shh pathway that regulates the actin cytoskeleton via Tiam1-Rac1 activation. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. The Molecular Motor KIF21B Mediates Synaptic Plasticity and Fear Extinction by Terminating Rac1 Activation.

    PubMed

    Morikawa, Momo; Tanaka, Yosuke; Cho, Hyun-Soo; Yoshihara, Masaharu; Hirokawa, Nobutaka

    2018-06-26

    Fear extinction is a component of cognitive flexibility that is relevant for important psychiatric diseases, but its molecular mechanism is still largely elusive. We established mice lacking the kinesin-4 motor KIF21B as a model for fear extinction defects. Postsynaptic NMDAR-dependent long-term depression (LTD) is specifically impaired in knockouts. NMDAR-mediated LTD-causing stimuli induce dynamic association of KIF21B with the Rac1GEF subunit engulfment and cell motility protein 1 (ELMO1), leading to ELMO1 translocation out of dendritic spines and its sequestration in endosomes. This process may essentially terminate transient activation of Rac1, shrink spines, facilitate AMPAR endocytosis, and reduce postsynaptic strength, thereby forming a mechanistic link to LTD expression. Antagonizing ELMO1/Dock Rac1GEF activity by the administration of 4-[3'-(2″-chlorophenyl)-2'-propen-1'-ylidene]-1-phenyl-3,5-pyrazolidinedione (CPYPP) significantly reverses the knockout phenotype. Therefore, we propose that KIF21B-mediated Rac1 inactivation is a key molecular event in NMDAR-dependent LTD expression underlying cognitive flexibility in fear extinction. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  1. 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 contractor...

  2. 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... Procedures for Energy Savings Performance Contracting § 436.32 Qualified contractors lists. (a) DOE shall... energy savings performance contracts. (c) DOE may remove a firm from DOE's list of qualified contractors...

  3. 21 CFR 21.30 - Records of contractors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Records of contractors. 21.30 Section 21.30 Food... PRIVACY Requirements for Specific Categories of Records § 21.30 Records of contractors. (a) Systems of... contractors to accomplish Food and Drug Administration functions, from which information is retrieved by...

  4. 21 CFR 20.90 - Disclosure to contractors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Disclosure to contractors. 20.90 Section 20.90... INFORMATION Limitations on Exemptions § 20.90 Disclosure to contractors. (a) Data and information otherwise exempt from public disclosure may be disclosed to contractors with the Food and Drug Administration and...

  5. 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 contractor...

  6. Rac1 Recruitment to the Archipelago Structure of the Focal Adhesion through the Fluid Membrane as Revealed by Single-Molecule Analysis

    PubMed Central

    Shibata, Akihiro C E; Chen, Limin H; Nagai, Rie; Ishidate, Fumiyoshi; Chadda, Rahul; Miwa, Yoshihiro; Naruse, Keiji; Shirai, Yuki M; Fujiwara, Takahiro K; Kusumi, Akihiro

    2013-01-01

    The focal adhesion (FA) is an integrin-based structure built in/on the plasma membrane (PM), linking the extracellular matrix to the actin stress-fibers, working as cell migration scaffolds. Previously, we proposed the archipelago architecture of the FA, in which FA largely consists of fluid membrane, dotted with small islands accumulating FA proteins: membrane molecules enter the inter-island channels in the FA zone rather freely, and the integrins in the FA-protein islands rapidly exchanges with those in the bulk membrane. Here, we examined how Rac1, a small G-protein regulating FA formation, and its activators αPIX and βPIX, are recruited to the FA zones. PIX molecules are recruited from the cytoplasm to the FA zones directly. In contrast, majorities of Rac1 molecules first arrive from the cytoplasm on the general inner PM surface, and then enter the FA zones via lateral diffusion on the PM, which is possible due to rapid Rac1 diffusion even within the FA zones, slowed only by a factor of two to four compared with that outside. The constitutively-active Rac1 mutant exhibited temporary and all-time immobilizations in the FA zone, suggesting that upon PIX-induced Rac1 activation at the FA-protein islands, Rac1 tends to be immobilized at the FA-protein islands. © 2013 Wiley Periodicals, Inc PMID:23341328

  7. Roles of STEF/Tiam1, guanine nucleotide exchange factors for Rac1, in regulation of growth cone morphology.

    PubMed

    Matsuo, Naoki; Terao, Mami; Nabeshima, Yo-ichi; Hoshino, Mikio

    2003-09-01

    Rho family GTPases are suggested to be pivotal for growth cone behavior, but regulation of their activities in response to environmental cues remains elusive. Here, we describe roles of STEF and Tiam1, guanine nucleotide exchange factors for Rac1, in neurite growth and growth cone remodeling. We reveal that, in primary hippocampal neurons, STEF/Tiam1 are localized within growth cones and essential for formation of growth cone lamellipodia, eventually contributing to neurite growth. Furthermore, experiments using a dominant-negative form demonstrate that STEF/Tiam1 mediate extracellular laminin signals to activate Rac1, promoting neurite growth in N1E-115 neuroblastoma cells. STEF/Tiam1 are revealed to mediate Cdc42 signal to activate Rac1 during lamellipodial formation. We also show that RhoA inhibits the STEF/Tiam1-Rac1 pathway. These data are used to propose a model that extracellular and intracellular information is integrated by STEF/Tiam1 to modulate the balance of Rho GTPase activities in the growth cone and, consequently, to control growth cone behavior.

  8. The Ribosome-Bound Chaperones RAC and Ssb1/2p Are Required for Accurate Translation in Saccharomyces cerevisiae

    PubMed Central

    Rakwalska, Magdalena; Rospert, Sabine

    2004-01-01

    The chaperone homologs RAC (ribosome-associated complex) and Ssb1/2p are anchored to ribosomes; Ssb1/2p directly interacts with nascent polypeptides. The absence of RAC or Ssb1/2p results in a similar set of phenotypes, including hypersensitivity against the aminoglycoside paromomycin, which binds to the small ribosomal subunit and compromises the fidelity of translation. In order to understand this phenomenon we measured the frequency of translation termination and misincorporation in vivo and in vitro with a novel reporter system. Translational fidelity was impaired in the absence of functional RAC or Ssb1/2p, and the effect was further enhanced by paromomycin. The mutant strains suffered primarily from a defect in translation termination, while misincorporation was compromised to a lesser extent. Consistently, a low level of soluble translation termination factor Sup35p enhanced growth defects in the mutant strains. Based on the combined data we conclude that RAC and Ssb1/2p are crucial in maintaining translational fidelity beyond their postulated role as chaperones for nascent polypeptides. PMID:15456889

  9. The ribosome-bound chaperones RAC and Ssb1/2p are required for accurate translation in Saccharomyces cerevisiae.

    PubMed

    Rakwalska, Magdalena; Rospert, Sabine

    2004-10-01

    The chaperone homologs RAC (ribosome-associated complex) and Ssb1/2p are anchored to ribosomes; Ssb1/2p directly interacts with nascent polypeptides. The absence of RAC or Ssb1/2p results in a similar set of phenotypes, including hypersensitivity against the aminoglycoside paromomycin, which binds to the small ribosomal subunit and compromises the fidelity of translation. In order to understand this phenomenon we measured the frequency of translation termination and misincorporation in vivo and in vitro with a novel reporter system. Translational fidelity was impaired in the absence of functional RAC or Ssb1/2p, and the effect was further enhanced by paromomycin. The mutant strains suffered primarily from a defect in translation termination, while misincorporation was compromised to a lesser extent. Consistently, a low level of soluble translation termination factor Sup35p enhanced growth defects in the mutant strains. Based on the combined data we conclude that RAC and Ssb1/2p are crucial in maintaining translational fidelity beyond their postulated role as chaperones for nascent polypeptides.

  10. 48 CFR 1552.237-76 - Government-Contractor Relations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: Government-Contractor Relations (JUN 1999) (a) The Government and the Contractor understand and agree that... event the notice is inadequate to make a decision, advise the Contractor what additional information is...

  11. 48 CFR 1552.237-76 - Government-Contractor Relations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: Government-Contractor Relations (JUN 1999) (a) The Government and the Contractor understand and agree that... event the notice is inadequate to make a decision, advise the Contractor what additional information is...

  12. General practitioners and the independent contractor status

    PubMed Central

    Gray, D. J. Pereira

    1977-01-01

    Primary medical care can be provided either by a bureaucratic hierarchical organization or alternatively by independent contractors. Most members of the caring professions in medicine, nursing, and social work are employed in bureaucracies, whereas general medical practitioners, general dental practitioners, opticians, and pharmacists are independent contractors. The independent contractor status has recently been heavily attacked from within the medical and nursing professions, and also from outside. It has been suggested that contracting for services is an inappropriate and anomalous way of arranging medical care, which should now be stopped. However, this process of contracting for services can be analysed, using perspectives from some of the behavioural sciences, to reveal hidden depths in the independent contractor status which suggest that the provision of primary medical care is best carried out by independent contractors. PMID:616865

  13. Prognostic role of integrin β1, E-cadherin, and rac1 expression in small cell lung cancer.

    PubMed

    Chang, Myung Hee; Lee, Kyungji; Lee, Kyo-Young; Kim, Yeon Sil; Kim, Young Kyoon; Kang, Jin-Hyoung

    2012-01-01

    Integrin β(1) mediates cellular adhesion to the extracellular matrix (ECM) and is correlated with highly invasive and metastatic behavior in small cell lung cancer (SCLC). E-cadherin (ECAD) is a calcium-dependent cell-cell adhesion receptor that restricts invasion of cells and reduces metastasis. Rac1 is involved in the regulation of the actin cytoskeleton, adhesion, migration, invasion, and tumor metastasis. The aim of this study was to examine integrin β(1) , ECAD and rac1 expression in SCLC and to analyze the prognostic value of these markers in patients with SCLC. We analyzed integrin β(1) , ECAD, and rac1 expression in 112 SCLC tissues by immunohistochemical staining. Correlative analyses between integrin β(1) , ECAD, and rac1 expression and cliniopathological factors were performed. A total of 65 patients had extensive disease (ED) (58%), and 47 had limited disease (LD) (42%). The median follow-up duration was 61 months (range: 14-117 months), and the median progression free survival (PFS) and overall survival (OS) were 6.1 months (range: 4.8-7.4 months) and 9.7 months (range: 8.1-11.3 months), respectively. The expression of integrin β(1) , ECAD, and rac1 protein was observed in 64, 73, and 99 of SCLC tissues, respectively. The correlative analyses between integrin β(1) , ECAD, or rac1 expression and various clinical parameters did not show any statistical significance. However, the ECAD expression was associated with OS in the entire cohort. In contrast, the expression of integrin β(1) and rac1 was not associated with PFS or OS. In a subgroup analysis, patients with less than two metastasis had significantly longer OS (p = 0.047) if their tumors expressed integrin β(1) compared to those without integrin β(1) expression. In addition, OS was longer for patients with ECAD positive tumors compared to those whose tumors did not express ECAD in males (p = 0.032) and patients who never smoked (p < 0.001). Multivariate analysis showed that LD (p = 0

  14. 41 CFR 60-741.44 - Required contents of affirmative action programs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affirmative action programs. 60-741.44 Section 60-741.44 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS REGARDING INDIVIDUALS WITH DISABILITIES Affirmative Action Program § 60-741.44 Required contents...

  15. Receptor-like kinases as surface regulators for RAC/ROP-mediated pollen tube growth and interaction with the pistil

    PubMed Central

    Zou, Yanjiao; Aggarwal, Mini; Zheng, Wen-Guang; Wu, Hen-Ming; Cheung, Alice Y.

    2011-01-01

    Background RAC/ROPs are RHO-type GTPases and are known to play diverse signalling roles in plants. Cytoplasmic RAC/ROPs are recruited to the cell membrane and activated in response to extracellular signals perceived and mediated by cell surface-located signalling assemblies, transducing the signals to regulate cellular processes. More than any other cell types in plants, pollen tubes depend on continuous interactions with an extracellular environment produced by their surrounding tissues as they grow within the female organ pistil to deliver sperm to the female gametophyte for fertilization. Scope We review studies on pollen tube growth that provide compelling evidence indicating that RAC/ROPs are crucial for regulating the cellular processes that underlie the polarized cell growth process. Efforts to identify cell surface regulators that mediate extracellular signals also point to RAC/ROPs being the molecular switches targeted by growth-regulating female factors for modulation to mediate pollination and fertilization. We discuss a large volume of work spanning more than two decades on a family of pollen-specific receptor kinases and some recent studies on members of the FERONIA family of receptor-like kinases (RLKs). Significance The research described shows the crucial roles that two RLK families play in transducing signals from growth regulatory factors to the RAC/ROP switch at the pollen tube apex to mediate and target pollen tube growth to the female gametophyte and signal its disintegration to achieve fertilization once inside the female chamber. PMID:22476487

  16. CCL21 mediates CD4+ T-cell costimulation via a DOCK2/Rac-dependent pathway.

    PubMed

    Gollmer, Kathrin; Asperti-Boursin, François; Tanaka, Yoshihiko; Okkenhaug, Klaus; Vanhaesebroeck, Bart; Peterson, Jeffrey R; Fukui, Yoshinori; Donnadieu, Emmanuel; Stein, Jens V

    2009-07-16

    CD4(+) T cells use the chemokine receptor CCR7 to home to and migrate within lymphoid tissue, where T-cell activation takes place. Using primary T-cell receptor (TCR)-transgenic (tg) CD4(+) T cells, we explored the effect of CCR7 ligands, in particular CCL21, on T-cell activation. We found that the presence of CCL21 during early time points strongly increased in vitro T-cell proliferation after TCR stimulation, correlating with increased expression of early activation markers. CCL21 costimulation resulted in increased Ras- and Rac-GTP formation and enhanced phosphorylation of Akt, MEK, and ERK but not p38 or JNK. Kinase-dead PI3Kdelta(D910A/D910A) or PI3Kgamma-deficient TCR-tg CD4(+) T cells showed similar responsiveness to CCL21 costimulation as control CD4(+) T cells. Conversely, deficiency in the Rac guanine exchange factor DOCK2 significantly impaired CCL21-mediated costimulation in TCR-tg CD4(+) T cells, concomitant with impaired Rac- but not Ras-GTP formation. Using lymph node slices for live monitoring of T-cell behavior and activation, we found that G protein-coupled receptor signaling was required for early CD69 expression but not for Ca(2+) signaling. Our data suggest that the presence of CCL21 during early TCR signaling lowers the activation threshold through Ras- and Rac-dependent pathways leading to increased ERK phosphorylation.

  17. A MAPK-Driven Feedback Loop Suppresses Rac Activity to Promote RhoA-Driven Cancer Cell Invasion

    PubMed Central

    Hetmanski, Joseph H. R.; Zindy, Egor; Schwartz, Jean-Marc; Caswell, Patrick T.

    2016-01-01

    Cell migration in 3D microenvironments is fundamental to development, homeostasis and the pathobiology of diseases such as cancer. Rab-coupling protein (RCP) dependent co-trafficking of α5β1 and EGFR1 promotes cancer cell invasion into fibronectin (FN) containing extracellular matrix (ECM), by potentiating EGFR1 signalling at the front of invasive cells. This promotes a switch in RhoGTPase signalling to inhibit Rac1 and activate a RhoA-ROCK-Formin homology domain-containing 3 (FHOD3) pathway and generate filopodial actin-spike protrusions which drive invasion. To further understand the signalling network that drives RCP-driven invasive migration, we generated a Boolean logical model based on existing network pathways/models, where each node can be interrogated by computational simulation. The model predicted an unanticipated feedback loop, whereby Raf/MEK/ERK signalling maintains suppression of Rac1 by inhibiting the Rac-activating Sos1-Eps8-Abi1 complex, allowing RhoA activity to predominate in invasive protrusions. MEK inhibition was sufficient to promote lamellipodia formation and oppose filopodial actin-spike formation, and led to activation of Rac and inactivation of RhoA at the leading edge of cells moving in 3D matrix. Furthermore, MEK inhibition abrogated RCP/α5β1/EGFR1-driven invasive migration. However, upon knockdown of Eps8 (to suppress the Sos1-Abi1-Eps8 complex), MEK inhibition had no effect on RhoGTPase activity and did not oppose invasive migration, suggesting that MEK-ERK signalling suppresses the Rac-activating Sos1-Abi1-Eps8 complex to maintain RhoA activity and promote filopodial actin-spike formation and invasive migration. Our study highlights the predictive potential of mathematical modelling approaches, and demonstrates that a simple intervention (MEK-inhibition) could be of therapeutic benefit in preventing invasive migration and metastasis. PMID:27138333

  18. Clustering of Rac1: Selective Lipid Sorting Drives Signaling.

    PubMed

    Maxwell, Kelsey N; Zhou, Yong; Hancock, John F

    2018-02-01

    The ability of lipid-anchored small GTPases to form nanometer-scale lipid domains on the cell plasma membrane (PM) is precipitating exciting new insights into membrane-anchored protein regulation. A recent article by Remorino et al. demonstrates that Rac1, similar to Ras, forms nanoclusters on the PM. The implications of these findings are discussed herein. Copyright © 2017. Published by Elsevier Ltd.

  19. In Situ Evaluation of the Role of the Small GTPase Rac3 in Breast Cancer

    DTIC Science & Technology

    2005-07-01

    in Figure 3a, total endogenous Rae protein expression remained equal among the cell variants. However, levels of active Rae ranged from highest in the...variants. a b Whole cell lysates of variants were 00 46M 4k& Total Rac Total Cdc42 subjected to SDS-PAGE followed by M -W Active Ra [ Active Cdc42 western...blot analysis for total Rac (a) 4o1o1....0 ........GTPa. +GTPS using an anti-R ac antibody and total _+ooP [ _]+GDP Cdc42 (b) using an anti-Cdc42

  20. 42 CFR 431.992 - Corrective action plan.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Estimating Improper Payments in Medicaid and CHIP § 431.992 Corrective action plan. (a) The State agency must develop a separate corrective action plan for Medicaid and CHIP, which is not required to be approved by... which the State's Medicaid or CHIP error rates are posted on the CMS contractor's Web site. (d) The...

  1. 42 CFR 431.992 - Corrective action plan.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Estimating Improper Payments in Medicaid and CHIP § 431.992 Corrective action plan. (a) The State agency must develop a separate corrective action plan for Medicaid and CHIP, which is not required to be approved by... which the State's Medicaid or CHIP error rates are posted on the CMS contractor's Web site. (d) The...

  2. 42 CFR 431.992 - Corrective action plan.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Estimating Improper Payments in Medicaid and CHIP § 431.992 Corrective action plan. (a) The State agency must develop a separate corrective action plan for Medicaid and CHIP, which is not required to be approved by... which the State's Medicaid or CHIP error rates are posted on the CMS contractor's Web site. (d) The...

  3. 41 CFR 60-1.31 - Reinstatement of ineligible contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ineligible contractors. 60-1.31 Section 60-1.31 Public Contracts and Property Management Other Provisions..., DEPARTMENT OF LABOR 1-OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS General Enforcement; Compliance Review and Complaint Procedure § 60-1.31 Reinstatement of ineligible contractors. A contractor debarred from...

  4. Mechanisms of splicing-dependent trans-synaptic adhesion by PTPδ-IL1RAPL1/IL-1RAcP for synaptic differentiation

    NASA Astrophysics Data System (ADS)

    Yamagata, Atsushi; Yoshida, Tomoyuki; Sato, Yusuke; Goto-Ito, Sakurako; Uemura, Takeshi; Maeda, Asami; Shiroshima, Tomoko; Iwasawa-Okamoto, Shiho; Mori, Hisashi; Mishina, Masayoshi; Fukai, Shuya

    2015-04-01

    Synapse formation is triggered through trans-synaptic interaction between pairs of pre- and postsynaptic adhesion molecules, the specificity of which depends on splice inserts known as `splice-insert signaling codes'. Receptor protein tyrosine phosphatase δ (PTPδ) can bidirectionally induce pre- and postsynaptic differentiation of neurons by trans-synaptically binding to interleukin-1 receptor accessory protein (IL-1RAcP) and IL-1RAcP-like-1 (IL1RAPL1) in a splicing-dependent manner. Here, we report crystal structures of PTPδ in complex with IL1RAPL1 and IL-1RAcP. The first immunoglobulin-like (Ig) domain of IL1RAPL1 directly recognizes the first splice insert, which is critical for binding to IL1RAPL1. The second splice insert functions as an adjustable linker that positions the Ig2 and Ig3 domains of PTPδ for simultaneously interacting with the Ig1 domain of IL1RAPL1 or IL-1RAcP. We further identified the IL1RAPL1-specific interaction, which appears coupled to the first-splice-insert-mediated interaction. Our results thus reveal the decoding mechanism of splice-insert signaling codes for synaptic differentiation induced by trans-synaptic adhesion between PTPδ and IL1RAPL1/IL-1RAcP.

  5. Quercetin protects liver injury induced by bile duct ligation via attenuation of Rac1 and NADPH oxidase1 expression in rats.

    PubMed

    Kabirifar, Razieh; Ghoreshi, Zohreh-Al-Sadat; Safari, Fatemeh; Karimollah, Alireza; Moradi, Ali; Eskandari-Nasab, Ebrahim

    2017-02-01

    Bile duct ligation (BDL) and subsequent cholestasis are correlated with oxidative stress, hepatocellular injury and fibrosis. Quercetin is a flavonoid with antifibrotic, and hepatoprotective properties. However, the molecular mechanism underlying quercetin-mediated hepatoprotection is not fully understood. The current study was to evaluate mechanisms of hepatoprotective effect of quercetin in BDL rat model. We divided male Wistar rats into 4 groups (n=8 for each): sham, sham+quercetin (30 mg/kg per day), BDL, and BDL+quercetin (30 mg/kg per day). Four weeks later, the rats were sacrificed, the blood was collected for liver enzyme measurements and liver for the measurement of Rac1, Rac1-GTP and NOX1 mRNA and protein levels by quantitative PCR and Western blotting, respectively. Quercetin significantly alleviated liver injury in BDL rats as evidenced by histology and reduced liver enzymes. Furthermore, the mRNA and protein expression of Rac1, Rac1-GTP and NOX1 were significantly increased in BDL rats compared with those in the sham group (P<0.05); quercetin treatment reversed these variables back toward normal (P<0.05). Another interesting finding was that the antioxidant markers e.g. superoxide dismutase and catalase were elevated in quercetin-treated BDL rats compared to BDL rats (P<0.05). Quercetin demonstrated hepatoprotective activity against BDL-induced liver injury through increasing antioxidant capacity of the liver tissue, while preventing the production of Rac1, Rac1-GTP and NOX1 proteins.

  6. The Small GTPase Rac1 Contributes to Extinction of Aversive Memories of Drug Withdrawal by Facilitating GABAA Receptor Endocytosis in the vmPFC.

    PubMed

    Wang, Weisheng; Ju, Yun-Yue; Zhou, Qi-Xin; Tang, Jian-Xin; Li, Meng; Zhang, Lei; Kang, Shuo; Chen, Zhong-Guo; Wang, Yu-Jun; Ji, Hui; Ding, Yu-Qiang; Xu, Lin; Liu, Jing-Gen

    2017-07-26

    Extinction of aversive memories has been a major concern in neuropsychiatric disorders, such as anxiety disorders and drug addiction. However, the mechanisms underlying extinction of aversive memories are not fully understood. Here, we report that extinction of conditioned place aversion (CPA) to naloxone-precipitated opiate withdrawal in male rats activates Rho GTPase Rac1 in the ventromedial prefrontal cortex (vmPFC) in a BDNF-dependent manner, which determines GABA A receptor (GABA A R) endocytosis via triggering synaptic translocation of activity-regulated cytoskeleton-associated protein (Arc) through facilitating actin polymerization. Active Rac1 is essential and sufficient for GABA A R endocytosis and CPA extinction. Knockdown of Rac1 expression within the vmPFC of rats using Rac1-shRNA suppressed GABA A R endocytosis and CPA extinction, whereas expression of a constitutively active form of Rac1 accelerated GABA A R endocytosis and CPA extinction. The crucial role of GABA A R endocytosis in the LTP induction and CPA extinction is evinced by the findings that blockade of GABA A R endocytosis by a dynamin function-blocking peptide (Myr-P4) abolishes LTP induction and CPA extinction. Thus, the present study provides first evidence that Rac1-dependent GABA A R endocytosis plays a crucial role in extinction of aversive memories and reveals the sequence of molecular events that contribute to learning experience modulation of synaptic GABA A R endocytosis. SIGNIFICANCE STATEMENT This study reveals that Rac1-dependent GABA A R endocytosis plays a crucial role in extinction of aversive memories associated with drug withdrawal and identifies Arc as a downstream effector of Rac1 regulations of synaptic plasticity as well as learning and memory, thereby suggesting therapeutic targets to promote extinction of the unwanted memories. Copyright © 2017 the authors 0270-6474/17/377096-15$15.00/0.

  7. 41 CFR 60-300.44 - Required contents of affirmative action programs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affirmative action programs. 60-300.44 Section 60-300.44 Public Contracts and Property Management Other... OPPORTUNITY, DEPARTMENT OF LABOR 300-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND... FORCES SERVICE MEDAL VETERANS Affirmative Action Program § 60-300.44 Required contents of affirmative...

  8. Rac1/WAVE2 and Cdc42/N-WASP Participation in Actin-Dependent Host Cell Invasion by Extracellular Amastigotes of Trypanosoma cruzi.

    PubMed

    Bonfim-Melo, Alexis; Ferreira, Éden R; Mortara, Renato A

    2018-01-01

    This study evaluated the participation of host cell Rho-family GTPases and their effector proteins in the actin-dependent invasion by Trypanosoma cruzi extracellular amastigotes (EAs). We observed that all proteins were recruited and colocalized with actin at EA invasion sites in live or fixed cells. EA internalization was inhibited in cells depleted in Rac1, N-WASP, and WAVE2. Time-lapse experiments with Rac1, N-WASP and WAVE2 depleted cells revealed that EA internalization kinetics is delayed even though no differences were observed in the proportion of EA-induced actin recruitment in these groups. Overexpression of constitutively active constructs of Rac1 and RhoA altered the morphology of actin recruitments to EA invasion sites. Additionally, EA internalization was increased in cells overexpressing CA-Rac1 but inhibited in cells overexpressing CA-RhoA. WT-Cdc42 expression increased EA internalization, but curiously, CA-Cdc42 inhibited it. Altogether, these results corroborate the hypothesis of EA internalization in non-phagocytic cells by a phagocytosis-like mechanism and present Rac1 as the key Rho-family GTPase in this process.

  9. 48 CFR 952.251-70 - Contractor employee travel discounts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor employee travel... Contractor employee travel discounts. As prescribed in 951.7002, insert the following clause: Contractor Employee Travel Discounts (AUG 2009) (a) The Contractor shall take advantage of travel discounts offered to...

  10. 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. ...

  11. RHOG-DOCK1-RAC1 Signaling Axis Is Perturbed in DHEA-Induced Polycystic Ovary in Rat Model.

    PubMed

    Ubba, Vaibhave; Soni, Upendra Kumar; Chadchan, Sangappa; Maurya, Vineet Kumar; Kumar, Vijay; Maurya, Ruchika; Chaturvedi, Himanshu; Singh, Rajender; Dwivedi, Anila; Jha, Rajesh Kumar

    2017-05-01

    The function of RHOG, a RAC1 activator, was explored in the ovary during ovarian follicular development and pathological conditions. With the help of immunoblotting and immunolocalization, we determined the expression and localization of RHOG in normal (estrous cycle) and polycystic ovaries using Sprague Dawley (SD) rat model. Employing polymerase chain reaction and flow cytometry, we analyzed the transcript and expression levels of downstream molecules of RHOG, DOCK1, and RAC1 in the polycystic ovarian syndrome (PCOS) ovary along with normal antral follicular theca and granulosa cells after dehydroepiandrosterone (DHEA) supplementation. The effect of RHOG knockdown on DOCK1, VAV, and RAC1 expression was evaluated in the human ovarian cells (SKOV3), theca cells, and granulosa cells from SD rats with the help of flow cytometry. Oocyte at secondary follicles along with stromal cells showed optimal expression of RHOG. Immunoblotting of RHOG revealed its maximum expression at diestrus and proestrus, which was downregulated at estrus stage. Mild immunostaining of RHOG was also present in the theca and granulosa cells of the secondary and antral follicles. Polycystic ovary exhibited weak immunostaining for RHOG and that was corroborated by immunoblotting-based investigations. RHOG effectors DOCK1 and ELMO1 were found reduced in the ovary in PCOS condition/DHEA. RHOG silencing reduced the expression of DOCK1 and RAC1 in the theca and granulosa cells from SD rat antral follicles and that was mirrored in the human ovarian cells. Collectively, RHOG can mediate signaling through downstream effectors DOCK1 and RAC1 during ovarian follicular development (theca and granulosa cells and oocyte), but DHEA downregulated them in the PCOS ovary.

  12. 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. ...

  13. 28 CFR 548.14 - Community involvement (volunteers, contractors).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., contractors). 548.14 Section 548.14 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE... Community involvement (volunteers, contractors). (a) The institution's chaplain may contract with... require a recognized representative of the faith group to verify a volunteer's or contractor's religious...

  14. 48 CFR 45.501 - Prime contractor alternate locations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Prime contractor alternate... CONTRACT MANAGEMENT GOVERNMENT PROPERTY Support Government Property Administration 45.501 Prime contractor... administration from another contract administration office, for purposes of evaluating prime contractor...

  15. 48 CFR 1852.209-72 - Composition of the contractor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contractor. 1852.209-72 Section 1852.209-72 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND... 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 legal...

  16. 40 CFR 35.938-6 - Progress payments to contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Progress payments to contractors. 35... § 35.938-6 Progress payments to contractors. (a) Policy. EPA policy is that, except as State law otherwise provides, grantees should make prompt progress payments to prime contractors and prime contractors...

  17. Generic radiological characterization protocol for surveys conducted for DOE remedial action programs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Berven, B.A.; Cottrell, W.D.; Leggett, R.W.

    1986-05-01

    This report describes goals and methodology that can be used by radiological survey contractors in surveys at properties associated with the Department of Energy's remedial action programs. The description includes: (1) a general discussion of the history of the remedial action programs; (2) the types of surveys that may be employed by the Radiological Survey Activities (RASA) contractor; (3) generic survey methods that may be used during radiological surveys; and (4) a format for presenting information and data in a survey report. 9 refs.

  18. CED-10/Rac1 Regulates Endocytic Recycling through the RAB-5 GAP TBC-2

    PubMed Central

    Sun, Lin; Liu, Ou; Desai, Jigar; Karbassi, Farhad; Sylvain, Marc-André; Shi, Anbing; Zhou, Zheng; Rocheleau, Christian E.; Grant, Barth D.

    2012-01-01

    Rac1 is a founding member of the Rho-GTPase family and a key regulator of membrane remodeling. In the context of apoptotic cell corpse engulfment, CED-10/Rac1 acts with its bipartite guanine nucleotide exchange factor, CED-5/Dock180-CED-12/ELMO, in an evolutionarily conserved pathway to promote phagocytosis. Here we show that in the context of the Caenorhabditis elegans intestinal epithelium CED-10/Rac1, CED-5/Dock180, and CED-12/ELMO promote basolateral recycling. Furthermore, we show that CED-10 binds to the RAB-5 GTPase activating protein TBC-2, that CED-10 contributes to recruitment of TBC-2 to endosomes, and that recycling cargo is trapped in recycling endosomes in ced-12, ced-10, and tbc-2 mutants. Expression of GTPase defective RAB-5(Q78L) also traps recycling cargo. Our results indicate that down-regulation of early endosome regulator RAB-5/Rab5 by a CED-5, CED-12, CED-10, TBC-2 cascade is an important step in the transport of cargo through the basolateral recycling endosome for delivery to the plasma membrane. PMID:22807685

  19. 48 CFR 53.209 - Contractor qualifications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Contractor qualifications. 53.209 Section 53.209 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION (CONTINUED) CLAUSES AND FORMS FORMS Prescription of Forms 53.209 Contractor qualifications. ...

  20. 48 CFR 1552.209-76 - Contractor performance evaluations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor performance... 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...

  1. 48 CFR 8.406-7 - Contractor Performance Evaluation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contractor Performance... ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Federal Supply Schedules 8.406-7 Contractor Performance Evaluation. Ordering activities must prepare an evaluation of contractor performance for each...

  2. 48 CFR 2936.201 - Evaluation of contractor performance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Evaluation of contractor... Construction 2936.201 Evaluation of contractor performance. The HCA must establish procedures to evaluate construction contractor performance and prepare performance reports as required by FAR 36.201. ...

  3. 48 CFR 32.909 - Contractor inquiries.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contractor inquiries. 32.909 Section 32.909 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Prompt Payment 32.909 Contractor inquiries. (a) Direct questions...

  4. Inhibition of Rac1 activity induces G1/S phase arrest through the GSK3/cyclin D1 pathway in human cancer cells.

    PubMed

    Liu, Linna; Zhang, Hongmei; Shi, Lei; Zhang, Wenjuan; Yuan, Juanli; Chen, Xiang; Liu, Juanjuan; Zhang, Yan; Wang, Zhipeng

    2014-10-01

    Rac1 has been shown to regulate the cell cycle in cancer cells. Yet, the related mechanism remains unclear. Thus, the present study aimed to investigate the mechanism involved in the regulation of G1/S phase transition by Rac1 in cancer cells. Inhibition of Rac1 by inhibitor NSC23766 induced G1/S phase arrest and inhibited the proliferation of A431, SW480 and U2-OS cells. Suppression of GSK3 by shRNA partially rescued G1/S phase arrest and inhibition of proliferation. Incubation of cells with NSC23766 reduced p-AKT and inactivated p-GSK3α and p-GSK3β, increased p-cyclin D1 expression and decreased the level of cyclin D1 protein. Consequently, cyclin D1 targeting transcriptional factor E2F1 expression, which promotes G1 to S phase transition, was also reduced. In contrast, constitutive active Rac1 resulted in increased p-AKT and inactivated p-GSK3α and p-GSK3β, decreased p-cyclin D1 expression and enhanced levels of cyclin D1 and E2F1 expression. Moreover, suppression of GSK3 did not alter p-AKT or Rac1 activity, but decreased p-cyclin D1 and increased total cyclin D1 protein. However, neither Rac1 nor GSK3 inhibition altered cyclin D1 at the RNA level. Moreover, after inhibition of Rac1 or GSK3 following proteasome inhibitor MG132 treatment, cyclin D1 expression at the protein level remained constant, indicating that Rac1 and GSK3 may regulate cyclin D1 turnover through phosphorylation and degradation. Therefore, our findings suggest that inhibition of Rac1 induces cell cycle G1/S arrest in cancer cells by regulation of the GSK3/cyclin D1 pathway.

  5. 48 CFR 970.5244-1 - Contractor purchasing system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... for Management and Operating Contracts 970.5244-1 Contractor purchasing system. As prescribed in 970... management system. The Contractor's approved purchasing system and methods shall include the requirements set... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Contractor purchasing...

  6. 48 CFR 2152.215-70 - Contractor records retention.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor records... PRECONTRACT PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 2152.215-70 Contractor records retention. As prescribed in 2115.071, insert the following clause: Contractor Records Retention (OCT 2005...

  7. 48 CFR 3036.201 - Evaluation of contractor performance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Evaluation of contractor performance. 3036.201 Section 3036.201 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY... contractor performance. (a)(2) Performance reports shall be prepared and entered into the Contractor...

  8. 48 CFR 36.506 - Superintendence by the contractor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contractor. 36.506 Section 36.506 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... Superintendence by the contractor. The contracting officer shall insert the clause at 52.236-6, Superintendence by the Contractor, in solicitations and contracts when a fixed-price construction contract or a fixed...

  9. 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 1999...

  10. 48 CFR 1652.204-70 - Contractor records retention.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor records... of FEHBP Clauses 1652.204-70 Contractor records retention. As prescribed in 1604.705 the following clause will be inserted in all FEHB Program contracts. Contractor Records Retention (JUL 2005...

  11. 41 CFR 60-741.40 - Applicability of the affirmative action program requirement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affirmative action program requirement. 60-741.40 Section 60-741.40 Public Contracts and Property Management... EMPLOYMENT OPPORTUNITY, DEPARTMENT OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS REGARDING INDIVIDUALS WITH DISABILITIES Affirmative Action Program § 60-741.40...

  12. 41 CFR 60-741.40 - Applicability of the affirmative action program requirement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affirmative action program requirement. 60-741.40 Section 60-741.40 Public Contracts and Property Management... EMPLOYMENT OPPORTUNITY, DEPARTMENT OF LABOR 741-AFFIRMATIVE ACTION AND NONDISCRIMINATION OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS REGARDING INDIVIDUALS WITH DISABILITIES Affirmative Action Program § 60-741.40...

  13. Iraq Reconstruction Project Terminations Represent a Range of Actions

    DTIC Science & Technology

    2008-10-27

    included in the FAR, Subpart 9.4. Contractors can be debarred for a number of criminal actions, including fraud, theft, embezzlement, bribery ...Poor performance alone, without any showing of fraud or unethical behavior, will not generally result in the contractor being suspended or debarred...taken in one instance but not in another. In the first instance, an Iraqi construction firm was debarred in June 2006 for allegations of bribery

  14. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE General 46.105 Contractor responsibilities. (a) The contractor is responsible for carrying out its obligations under the contract by— (1) Controlling the quality of supplies or..., subassemblies, etc., have an acceptable quality control system; and (4) Maintaining substantiating evidence...

  15. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE General 46.105 Contractor responsibilities. (a) The contractor is responsible for carrying out its obligations under the contract by— (1) Controlling the quality of supplies or..., subassemblies, etc., have an acceptable quality control system; and (4) Maintaining substantiating evidence...

  16. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE General 46.105 Contractor responsibilities. (a) The contractor is responsible for carrying out its obligations under the contract by— (1) Controlling the quality of supplies or..., subassemblies, etc., have an acceptable quality control system; and (4) Maintaining substantiating evidence...

  17. 48 CFR 46.105 - Contractor responsibilities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE General 46.105 Contractor responsibilities. (a) The contractor is responsible for carrying out its obligations under the contract by— (1) Controlling the quality of supplies or..., subassemblies, etc., have an acceptable quality control system; and (4) Maintaining substantiating evidence...

  18. 48 CFR 4.102 - Contractor's signature.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contractor's signature. 4.102 Section 4.102 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL ADMINISTRATIVE MATTERS Contract Execution 4.102 Contractor's signature. (a) Individuals. A contract with an...

  19. 48 CFR 253.209 - Contractor qualifications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 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. The contractor`s role in low-level waste disposal facility application review and licensing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 inmore » 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.« less

  1. CDKL5, a protein associated with rett syndrome, regulates neuronal morphogenesis via Rac1 signaling.

    PubMed

    Chen, Qian; Zhu, Yong-Chuan; Yu, Jing; Miao, Sheng; Zheng, Jing; Xu, Li; Zhou, Yang; Li, Dan; Zhang, Chi; Tao, Jiong; Xiong, Zhi-Qi

    2010-09-22

    Mutations in cyclin-dependent kinase-like 5 (CDKL5), also known as serine/threonine kinase 9 (STK9), have been identified in patients with Rett syndrome (RTT) and X-linked infantile spasm. However, the function of CDKL5 in the brain remains unknown. Here, we report that CDKL5 is a critical regulator of neuronal morphogenesis. We identified a neuron-specific splicing variant of CDKL5 whose expression was markedly induced during postnatal development of the rat brain. Downregulating CDKL5 by RNA interference (RNAi) in cultured cortical neurons inhibited neurite growth and dendritic arborization, whereas overexpressing CDKL5 had opposite effects. Furthermore, knocking down CDKL5 in the rat brain by in utero electroporation resulted in delayed neuronal migration, and severely impaired dendritic arborization. In contrast to its proposed function in the nucleus, we found that CDKL5 regulated dendrite development through a cytoplasmic mechanism. In fibroblasts and in neurons, CDKL5 colocalized and formed a protein complex with Rac1, a critical regulator of actin remodeling and neuronal morphogenesis. Overexpression of Rac1 prevented the inhibition of dendrite growth caused by CDKL5 knockdown, and the growth-promoting effect of ectopically expressed CDKL5 on dendrites was abolished by coexpressing a dominant-negative form of Rac1. Moreover, CDKL5 was required for brain-derived neurotrophic factor (BDNF)-induced activation of Rac1. Together, these results demonstrate a critical role of CDKL5 in neuronal morphogenesis and identify a Rho GTPase signaling pathway which may contribute to CDKL5-related disorders.

  2. 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.

  3. 48 CFR 252.242-7005 - Contractor business systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 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, use the following clause: Contractor Business Systems (FEB 2012) (a) This clause only applies to covered...

  4. 48 CFR 252.242-7005 - Contractor business systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 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, use the following clause: Contractor Business Systems (FEB 2012) (a) This clause only applies to covered...

  5. 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 clause...

  6. 48 CFR 252.242-7005 - Contractor business systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 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, use the following clause: Contractor Business Systems (FEB 2012) (a) This clause only applies to covered...

  7. 48 CFR 53.209-1 - Responsible prospective contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contractors. 53.209-1 Section 53.209-1 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION (CONTINUED) CLAUSES AND FORMS FORMS Prescription of Forms 53.209-1 Responsible prospective contractors. (a) SF 1403 (Rev. 9/88), Preaward Survey of Prospective Contractor (General). SF 1403 is authorized for...

  8. Identification of a RAC/AKT-like gene in Leishmania parasites as a putative therapeutic target in leishmaniasis.

    PubMed

    Varela-M, Rubén E; Ochoa, Rodrigo; Muskus, Carlos E; Muro, Antonio; Mollinedo, Faustino

    2017-10-10

    Leishmaniasis is one of the world's most neglected diseases caused by at least 20 different species of the protozoan parasite Leishmania. Although new drugs have become recently available, current therapy for leishmaniasis is still unsatisfactory. A subgroup of serine/threonine protein kinases named as related to A and C protein kinases (RAC), or protein kinase B (PKB)/AKT, has been identified in several organisms including Trypanosoma cruzi parasites. PKB/AKT plays a critical role in mammalian cell signaling promoting cell survival and is a major drug target in cancer therapy. However, the role of protozoan parasitic PKB/AKT remains to be elucidated. We have found that anti-human AKT antibodies recognized a protein of about 57 kDa in Leishmania spp. parasites. Anti-human phospho-AKT(Thr308) antibodies identified a protein in extracts from Leishmania spp. that was upregulated following parasite exposure to stressful conditions, such as nutrient deprivation or heat shock. Incubation of AKT inhibitor X with Leishmania spp. promastigotes under stressful conditions or with Leishmania-infected macrophages led to parasite cell death. We have identified and cloned a novel gene from Leishmania donovani named Ld-RAC/AKT-like gene, encoding a 510-amino acid protein of approximately 57.6 kDa that shows a 26.5% identity with mammalian AKT1. Ld-RAC/AKT-like protein contains major mammalian PKB/AKT hallmarks, including the typical pleckstrin, protein kinase and AGC kinase domains. Unlike mammalian AKT that contains key phosphorylation sites at Thr308 and Ser473 in the activation loop and hydrophobic motif, respectively, Ld-RAC/AKT-like protein has a Thr residue in both motifs. By domain sequence comparison, we classified AKT proteins from different origins in four major subcategories that included different parasites. Our data suggest that Ld-RAC/AKT-like protein represents a Leishmania orthologue of mammalian AKT involved in parasite stress response and survival, and

  9. PI3K regulates MEK/ERK signaling in breast cancer via the Rac-GEF, P-Rex1

    PubMed Central

    Ebi, Hiromichi; Costa, Carlotta; Faber, Anthony C.; Nishtala, Madhuri; Kotani, Hiroshi; Juric, Dejan; Della Pelle, Patricia; Song, Youngchul; Yano, Seiji; Mino-Kenudson, Mari; Benes, Cyril H.; Engelman, Jeffrey A.

    2013-01-01

    The PI3K pathway is genetically altered in excess of 70% of breast cancers, largely through PIK3CA mutation and HER2 amplification. Preclinical studies have suggested that these subsets of breast cancers are particularly sensitive to PI3K inhibitors; however, the reasons for this heightened sensitivity are mainly unknown. We investigated the signaling effects of PI3K inhibition in PIK3CA mutant and HER2 amplified breast cancers using PI3K inhibitors currently in clinical trials. Unexpectedly, we found that in PIK3CA mutant and HER2 amplified breast cancers sensitive to PI3K inhibitors, PI3K inhibition led to a rapid suppression of Rac1/p21-activated kinase (PAK)/protein kinase C-RAF (C-RAF)/ protein kinase MEK (MEK)/ERK signaling that did not involve RAS. Furthermore, PI3K inhibition led to an ERK-dependent up-regulation of the proapoptotic protein, BIM, followed by induction of apoptosis. Expression of a constitutively active form of Rac1 in these breast cancer models blocked PI3Ki-induced down-regulation of ERK phosphorylation, apoptosis, and mitigated PI3K inhibitor sensitivity in vivo. In contrast, protein kinase AKT inhibitors failed to block MEK/ERK signaling, did not up-regulate BIM, and failed to induce apoptosis. Finally, we identified phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) as the PI(3,4,5)P3-dependent guanine exchange factor for Rac1 responsible for regulation of the Rac1/C-RAF/MEK/ERK pathway in these cells. The expression level of P-Rex1 correlates with sensitivity to PI3K inhibitors in these breast cancer cell lines. Thus, PI3K inhibitors have enhanced activity in PIK3CA mutant and HER2 amplified breast cancers in which PI3K inhibition down-regulates both the AKT and Rac1/ERK pathways. In addition, P-Rex1 may serve as a biomarker to predict response to single-agent PI3K inhibitors within this subset of breast cancers. PMID:24327733

  10. Histamine acting on H1 receptor promotes inhibition of proliferation via PLC, RAC, and JNK-dependent pathways

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Notcovich, Cintia; Laboratorio de Farmacologia de Receptores, Catedra de Quimica Medicinal, Departamento de Farmacologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires; Diez, Federico

    2010-02-01

    It is well established that histamine modulates cell proliferation through the activation of the histamine H1 receptor (H1R), a G protein-coupled receptor (GPCR) that is known to couple to phospholipase C (PLC) activation via Gq. In the present study, we aimed to determine whether H1R activation modulates Rho GTPases, well-known effectors of Gq/G{sub 11}-coupled receptors, and whether such modulation influences cell proliferation. Experiments were carried out in CHO cells stably expressing H1R (CHO-H1R). By using pull-down assays, we found that both histamine and a selective H1R agonist activated Rac and RhoA in a time- and dose-dependent manner without significant changesmore » in the activation of Cdc42. Histamine response was abolished by the H1R antagonist mepyramine, RGS2 and the PLC inhibitor U73122, suggesting that Rac and RhoA activation is mediated by H1R via Gq coupling to PLC stimulation. Histamine caused a marked activation of serum response factor activity via the H1R, as determined with a serum-responsive element (SRE) luciferase reporter, and this response was inhibited by RhoA inactivation with C3 toxin. Histamine also caused a significant activation of JNK which was inhibited by expression of the Rac-GAP {beta}2-chimaerin. On the other hand, H1R-induced ERK1/2 activation was inhibited by U73122 but not affected by C3 or {beta}2-chimaerin, suggesting that ERK1/2 activation was dependent on PLC and independent of RhoA or Rac. [{sup 3}H]-Thymidine incorporation assays showed that both histamine and the H1R agonist inhibited cell proliferation in a dose-dependent manner and that the effect was independent of RhoA but partially dependent on JNK and Rac. Our results reveal that functional coupling of the H1R to Gq-PLC leads to the activation of RhoA and Rac small GTPases and suggest distinct roles for Rho GTPases in the control of cell proliferation by histamine.« less

  11. 48 CFR 1845.7209-3 - Loss, damage, or destruction of Government property while in contractor's possession or control.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... (b) When physical inventories, consumption analyses, or other actions disclose consumption of... required to reach a valid and supportable conclusion as to the contractor's liability for the loss, damage... assure proper credit. If analysis of contract provisions and circumstances establishes that the loss...

  12. 30 CFR 874.16 - Contractor eligibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Contractor eligibility. 874.16 Section 874.16 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR ABANDONED MINE LAND RECLAMATION GENERAL RECLAMATION REQUIREMENTS § 874.16 Contractor eligibility. To receive...

  13. 30 CFR 875.20 - Contractor eligibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Contractor eligibility. 875.20 Section 875.20 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR ABANDONED MINE LAND RECLAMATION CERTIFICATION AND NONCOAL RECLAMATION § 875.20 Contractor eligibility. Every...

  14. Contractor Motivation Theory and Applications.

    DTIC Science & Technology

    1981-03-01

    Project Officer, Chief, Test and Evaluation Group , US Army Procurement Research Office, ALMC. BS, Aeronautical Engineering, University of Wyoming, 1963...Contractor Motivation Theory and Applications SEE DISTRIBUTION Inclosed is a copy of subject report for your use . This report describes the DOD contractor...motivation process and various areas for improvement. In particular, it identifies effective incentives that can be used and recommends policy that

  15. 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 joint...

  16. 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 joint...

  17. 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 joint...

  18. 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 or...

  19. 7 CFR 3015.183 - Access to contractor records.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Access to contractor records. 3015.183 Section 3015... contractor records. The Attachment 0 requires recipients to include in specified kinds of contracts a provision for access to the contractor's records by the recipient and the Federal government. The following...

  20. 4 CFR 75.1 - Contractors' and vendors' certificates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 4 Accounts 1 2010-01-01 2010-01-01 false Contractors' and vendors' certificates. 75.1 Section 75.1... BASIC VOUCHERS AND INVOICES § 75.1 Contractors' and vendors' certificates. (a) The Government... bills and invoices of contractors and vendors, with the exception that carriers, or other corporations...

  1. Inhibition of GTPase Rac1 in endothelium by 6-mercaptopurine results in immunosuppression in nonimmune cells: new target for an old drug.

    PubMed

    Marinković, Goran; Kroon, Jeffrey; Hoogenboezem, Mark; Hoeben, Kees A; Ruiter, Matthijs S; Kurakula, Kondababu; Otermin Rubio, Iker; Vos, Mariska; de Vries, Carlie J M; van Buul, Jaap D; de Waard, Vivian

    2014-05-01

    Azathioprine and its metabolite 6-mercaptopurine (6-MP) are well established immunosuppressive drugs. Common understanding of their immunosuppressive properties is largely limited to immune cells. However, in this study, the mechanism underlying the protective role of 6-MP in endothelial cell activation is investigated. Because 6-MP and its derivative 6-thioguanosine-5'-triphosphate (6-T-GTP) were shown to block activation of GTPase Rac1 in T lymphocytes, we focused on Rac1-mediated processes in endothelial cells. Indeed, 6-MP and 6-T-GTP decreased Rac1 activation in endothelial cells. As a result, the compounds inhibited TNF-α-induced downstream signaling via JNK and reduced activation of transcription factors c-Jun, activating transcription factor-2 and, in addition, NF κ-light-chain-enhancer of activated B cells (NF-κB), which led to decreased transcription of proinflammatory cytokines. Moreover, 6-MP and 6-T-GTP selectively decreased TNF-α-induced VCAM-1 but not ICAM-1 protein levels. Rac1-mediated generation of cell membrane protrusions, which form docking structures to capture leukocytes, also was reduced by 6-MP/6-T-GTP. Consequently, leukocyte transmigration was inhibited after 6-MP/6-T-GTP treatment. These data underscore the anti-inflammatory effect of 6-MP and 6-T-GTP on endothelial cells by blocking Rac1 activation. Our data provide mechanistic insight that supports development of novel Rac1-specific therapeutic approaches against chronic inflammatory diseases.

  2. Role of Rac1/WAVE2 Signaling in Mediating the Inhibitory Effects of γ-Tocotrienol on Mammary Cancer Cell Migration and Invasion.

    PubMed

    Algayadh, Ibrahim Gayadh; Dronamraju, Venkateshwararao; Sylvester, Paul William

    2016-01-01

    The majority of breast cancer deaths result from the progression of this disease to a metastatic phenotype. Rac1 and Cdc42 are Rho family members that together with their downstream effectors, Wiskott-Aldrich Syndrome protein-family verprolin-homologous protein 2 (WAVE2) and Arp2/3, play an important role in cytoskeletal reorganization and the formation of membrane protrusions that promote cancer cell migration and invasion. γ-Tocotrienol, is a natural isoform within the vitamin E family of compounds that inhibits breast cancer cell growth and progression by suppressing various signaling pathways involved in mitogenic signaling and metastatic progression. Studies were conducted to examine the effects of γ-tocotrienol on Rac1/WAVE2 signaling dependent migration and invasion in highly metastatic mouse +SA and human MDA-MB-231 mammary cancer cells. Exposure to γ-tocotrienol resulted in a dose-responsive decrease in Rac1/WAVE2 signaling as characterized by a suppression in the levels of Rac1/Cdc42, phospho-Rac1/Cdc42, WAVE2, Arp2, and Arp3 expression. Additional studies also demonstrated that similar treatment with γ-tocotrienol resulted in a significant reduction in tumor cell migration and invasion. Taken together, these findings indicate that γ-tocotrienol treatment effectively inhibits Rac1/WAVE2 signaling and reduces metastatic phenotypic expression in mammary cancer cells, suggesting that γ-tocotrienol may provide some benefit as a novel therapeutic approach in the treatment of metastatic breast cancer.

  3. A Prenylated p47phox-p67phox-Rac1 Chimera Is a Quintessential NADPH Oxidase Activator

    PubMed Central

    Mizrahi, Ariel; Berdichevsky, Yevgeny; Casey, Patrick J.; Pick, Edgar

    2010-01-01

    The superoxide-generating NADPH oxidase complex of resting phagocytes includes cytochrome b559, a membrane-associated heterodimer composed of two subunits (Nox2 and p22phox), and four cytosolic proteins (p47phox, p67phox, Rac, and p40phox). Upon stimulation, the cytosolic components translocate to the membrane, as the result of a series of interactions among the cytosolic components and among the cytosolic components and cytochrome b559 and its phospholipid environment. We described the construction of a tripartite chimera (trimera) consisting of strategic domains of p47phox, p67phox, and Rac1, in which interactions among cytosolic components were replaced by fusion (Berdichevsky, Y., Mizrahi, A., Ugolev, Y., Molshanski-Mor, S., and Pick, E. (2007) J. Biol. Chem. 282, 22122–22139). We now fused green fluorescent protein (GFP) to the N terminus of the trimera and found the following. 1) The GFP-p47phox-p67phox-Rac1 trimera activates the oxidase in amphiphile-dependent and -independent (anionic phospholipid-enriched membrane) cell-free systems. 2) Geranylgeranylation of the GFP-trimera makes it a potent oxidase activator in unmodified (native) membranes and in the absence of amphiphile. 3) Prenylated GFP-trimera binds spontaneously to native membranes (as assessed by gel filtration and in-line fluorometry), forming a tight complex capable of NADPH-dependent, activator-independent superoxide production at rates similar to those measured in canonical cell-free systems. 4) Prenylation of the GFP-trimera supersedes completely the dependence of oxidase activation on the p47phox phox homology domain and, partially, on the Rac1 polybasic domain, but the requirement for Trp193 in p47phox persists. Prenylated GFP-p47phox-p67phox-Rac1 trimera acts as a quintessential single molecule oxidase activator of potential use in high throughput screening of inhibitors. PMID:20529851

  4. Rac1/WAVE2 and Cdc42/N-WASP Participation in Actin-Dependent Host Cell Invasion by Extracellular Amastigotes of Trypanosoma cruzi

    PubMed Central

    Bonfim-Melo, Alexis; Ferreira, Éden R.; Mortara, Renato A.

    2018-01-01

    This study evaluated the participation of host cell Rho-family GTPases and their effector proteins in the actin-dependent invasion by Trypanosoma cruzi extracellular amastigotes (EAs). We observed that all proteins were recruited and colocalized with actin at EA invasion sites in live or fixed cells. EA internalization was inhibited in cells depleted in Rac1, N-WASP, and WAVE2. Time-lapse experiments with Rac1, N-WASP and WAVE2 depleted cells revealed that EA internalization kinetics is delayed even though no differences were observed in the proportion of EA-induced actin recruitment in these groups. Overexpression of constitutively active constructs of Rac1 and RhoA altered the morphology of actin recruitments to EA invasion sites. Additionally, EA internalization was increased in cells overexpressing CA-Rac1 but inhibited in cells overexpressing CA-RhoA. WT-Cdc42 expression increased EA internalization, but curiously, CA-Cdc42 inhibited it. Altogether, these results corroborate the hypothesis of EA internalization in non-phagocytic cells by a phagocytosis-like mechanism and present Rac1 as the key Rho-family GTPase in this process. PMID:29541069

  5. 48 CFR 3052.204-71 - Contractor employee access.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Contractor employee access... CLAUSES Text of Provisions and Clauses 3052.204-71 Contractor employee access. As prescribed in (HSAR) 48...: Contractor Employee Access (JUN 2006) (a) “Sensitive Information,” as used in this Chapter, means any...

  6. 78 FR 51658 - Weighing, Feed, and Swine Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-21

    ... RIN 0580-AA99 Weighing, Feed, and Swine Contractors AGENCY: Grain Inspection, Packers and Stockyards... and swine contractors to poultry and swine production contract growers are based on accurate weighing... reweighing to add swine contractors to the list of firms that must comply, and adding feed to the list of...

  7. Rac1 modulates the formation of primordial follicles by facilitating STAT3-directed Jagged1, GDF9 and BMP15 transcription in mice

    PubMed Central

    Zhao, Lihua; Du, Xinhua; Huang, Kun; Zhang, Tuo; Teng, Zhen; Niu, Wanbao; Wang, Chao; Xia, Guoliang

    2016-01-01

    The size of the primordial follicle pool determines the reproductive potential of mammalian females, and establishment of the pool is highly dependent on specific genes expression. However, the molecular mechanisms by which the essential genes are regulated coordinately to ensure primordial follicle assembly remain a mystery. Here, we show that the small GTPase Rac1 plays an indispensable role in controlling the formation of primordial follicles in mouse ovary. Employing fetal mouse ovary organ culture system, we demonstrate that disruption of Rac1 retarded the breakdown of germline cell cysts while Rac1 overexpression accelerated the formation of primordial follicles. In addition, in vivo inhibitor injection resulted in the formation of multi-oocyte follicles. Subsequent investigation showed that Rac1 induced nuclear import of STAT3 by physical binding. In turn, nuclear STAT3 directly activated the transcription of essential oocyte-specific genes, including Jagged1, GDF9, BMP15 and Nobox. Further, GDF9 and BMP15 regulated the translation of Notch2 via mTORC1 activation in pregranulosa cells. Overexression or addition of Jagged1, GDF9 and BMP15 not only reversed the effect of Rac1 disruption, but also accelerated primordial follicle formation via Notch2 signaling activation. Collectively, these results indicate that Rac1 plays important roles as a key regulator in follicular assembly. PMID:27050391

  8. Contractor Accounting, Reporting and Estimating (CARE).

    DTIC Science & Technology

    Contractor Accounting Reporting and Estimating (CARE) provides check lists that may be used as guides in evaluating the accounting system, financial reporting , and cost estimating capabilities of the contractor. Experience gained from the Management Review Technique was used as a basis for the check lists. (Author)

  9. Maintenance and operations contractor plan for transition to the project Hanford management contract (PHMC)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 impactmore » 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.« less

  10. Differential regulation of the Rac1 GTPase-activating protein (GAP) BCR during oxygen/glucose deprivation in hippocampal and cortical neurons.

    PubMed

    Smith, Katharine R; Rajgor, Dipen; Hanley, Jonathan G

    2017-12-08

    Brain ischemia causes oxygen and glucose deprivation (OGD) in neurons, triggering a cascade of events leading to synaptic accumulation of glutamate. Excessive activation of glutamate receptors causes excitotoxicity and delayed cell death in vulnerable neurons. Following global cerebral ischemia, hippocampal CA1 pyramidal neurons are more vulnerable to injury than their cortical counterparts, but the mechanisms that underlie this difference are unclear. Signaling via Rho-family small GTPases, their upstream guanine nucleotide exchange factors, and GTPase-activating proteins (GAPs) is differentially dysregulated in response to OGD/ischemia in hippocampal and cortical neurons. Increased Rac1 activity caused by OGD/ischemia contributes to neuronal death in hippocampal neurons via diverse effects on NADPH oxidase activity and dendritic spine morphology. The Rac1 guanine nucleotide exchange factor Tiam1 mediates an OGD-induced increase in Rac1 activity in hippocampal neurons; however, the identity of an antagonistic GAP remains elusive. Here we show that the Rac1 GAP breakpoint cluster region (BCR) associates with NMDA receptors (NMDARs) along with Tiam1 and that this protein complex is more abundant in hippocampal compared with cortical neurons. Although total BCR is similar in the two neuronal types, BCR is more active in hippocampal compared with cortical neurons. OGD causes an NMDAR- and Ca 2+ -permeable AMPAR-dependent deactivation of BCR in hippocampal but not cortical neurons. BCR knockdown occludes OGD-induced Rac1 activation in hippocampal neurons. Furthermore, disrupting the Tiam1-NMDAR interaction with a fragment of Tiam1 blocks OGD-induced Tiam1 activation but has no effect on the deactivation of BCR. This work identifies BCR as a critical player in Rac1 regulation during OGD in hippocampal neurons. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. 48 CFR 945.610-4 - Contractor inventory in foreign countries.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor inventory in... CONTRACT MANAGEMENT GOVERNMENT PROPERTY Reporting, Redistribution, and Disposal of Contractor Inventory 945.610-4 Contractor inventory in foreign countries. Contractor inventory located in foreign countries...

  12. 41 CFR 109-43.302-50 - Utilization by designated contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... designated contractors. 109-43.302-50 Section 109-43.302-50 Public Contracts and Property Management Federal... Utilization by designated contractors. Heads of field organizations may authorize designated contractors to... Federal agency, provided the designated contractors have written policies and procedures. ...

  13. 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 contract...

  14. 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 contract...

  15. 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 contract...

  16. 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 contract...

  17. Impacts of Rac- and S-metolachlor on cyanobacterial cell integrity and release of microcystins at different nitrogen levels.

    PubMed

    Wang, Jia; Zhang, Lijuan; Fan, Jiajia; Wen, Yuezhong

    2017-08-01

    Pesticide residues and nitrogen overload (which caused cyanobacteria blooms) have been two serious environmental concerns. In particular, chiral pesticides with different structures may have various impacts on cyanobacteria. Nitrogen may affect the behavior between pesticides and cyanobacteria (e.g., increase the adverse effects of pesticides on cyanobacteria). This study evaluated the impacts of Rac- and S-metolachlor on the cell integrity and toxin release of Microcystis aeruginosa cells at different nitrogen levels. The results showed that (both of the configurations: Rac-, S-) metolachlor could inhibit M. aeruginosa cell growth under most conditions, and the inhibition rates were increased with the growing concentrations of nitrogen and metolachlor. However, cyanobacterial growth was promoted in 48 h under environmental relevant condition (1 mg/L metolachlor and 0.15 mg/L nitrogen). Therefore, the water authorities should adjust the treatment parameters to remove possible larger numbers of cyaonbacteria under that condition. On the other hand, the inhibition degree of M. aeruginosa cell growth by S-metolachlor treatments was obviously larger than Rac-metolachlor treatments. S-metolachlor also had a stronger ability in compromising M. aeruginosa cells than Rac-metolachlor treatments. Compared to control samples, more extracellular toxins (12%-86% increases) were detected after 5 mg/L S-metolachlor treatment for 72 h at different nitrogen levels, but the variations of extracellular toxins caused by 5 mg/L Rac-metolachlor addition could be neglected. Consequently, higher concentrations of metolachlor in source waters are harmful to humans, but it may prevent cyanobacterial blooms. However, the potential risks (e.g. build-up of extracellular toxins) should be considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. 75 FR 64741 - Notice of Utah's Resource Advisory Council (RAC) Subcommittee Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-20

    ...In accordance with the Federal Land Policy and Management Act (FLPMA) and the Federal Advisory Committee Act of 1972, the U.S. Department of the Interior, Bureau of Land Management's (BLM) Utah Resource Advisory Council (RAC) Subcommittee will meet as indicated below.

  19. Tiam1 interaction with the PAR complex promotes talin-mediated Rac1 activation during polarized cell migration

    PubMed Central

    Wang, Shujie; Watanabe, Takashi; Matsuzawa, Kenji; Katsumi, Akira; Kakeno, Mai; Matsui, Toshinori; Ye, Feng; Sato, Kazuhide; Murase, Kiyoko; Sugiyama, Ikuko; Kimura, Kazushi; Mizoguchi, Akira; Ginsberg, Mark H.; Collard, John G.

    2012-01-01

    Migrating cells acquire front-rear polarity with a leading edge and a trailing tail for directional movement. The Rac exchange factor Tiam1 participates in polarized cell migration with the PAR complex of PAR3, PAR6, and atypical protein kinase C. However, it remains largely unknown how Tiam1 is regulated and contributes to the establishment of polarity in migrating cells. We show here that Tiam1 interacts directly with talin, which binds and activates integrins to mediate their signaling. Tiam1 accumulated at adhesions in a manner dependent on talin and the PAR complex. The interactions of talin with Tiam1 and the PAR complex were required for adhesion-induced Rac1 activation, cell spreading, and migration toward integrin substrates. Furthermore, Tiam1 acted with talin to regulate adhesion turnover. Thus, we propose that Tiam1, with the PAR complex, binds to integrins through talin and, together with the PAR complex, thereby regulates Rac1 activity and adhesion turnover for polarized migration. PMID:23071154

  20. 76 FR 37704 - Federal Acquisition Regulation; Documenting Contractor Performance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-28

    ... Federal Acquisition Regulation; Documenting Contractor Performance AGENCY: Department of Defense (DoD..., and to require all past performance information be entered into the Contractor Performance Assessment... Contractor Performance Information. These changes provide Governmentwide standardized evaluation factors and...

  1. 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.

  2. 48 CFR 1852.242-73 - NASA contractor financial management reporting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false NASA contractor financial... Provisions and Clauses 1852.242-73 NASA contractor financial management reporting. As prescribed in 1842.7202, insert the following clause: NASA Contractor Financial Management Reporting (NOV 2004) (a) The Contractor...

  3. 48 CFR 1852.242-73 - NASA contractor financial management reporting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false NASA contractor financial... Provisions and Clauses 1852.242-73 NASA contractor financial management reporting. As prescribed in 1842.7202, insert the following clause: NASA Contractor Financial Management Reporting (NOV 2004) (a) The Contractor...

  4. 48 CFR 1852.242-73 - NASA contractor financial management reporting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false NASA contractor financial... Provisions and Clauses 1852.242-73 NASA contractor financial management reporting. As prescribed in 1842.7202, insert the following clause: NASA Contractor Financial Management Reporting (NOV 2004) (a) The Contractor...

  5. 48 CFR 1852.242-73 - NASA contractor financial management reporting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false NASA contractor financial... Provisions and Clauses 1852.242-73 NASA contractor financial management reporting. As prescribed in 1842.7202, insert the following clause: NASA Contractor Financial Management Reporting (NOV 2004) (a) The Contractor...

  6. 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 personnel...

  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 personnel...

  8. 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 personnel...

  9. 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 personnel...

  10. Apollo experience report: Problem reporting and corrective action system

    NASA Technical Reports Server (NTRS)

    Adams, T. J.

    1974-01-01

    The Apollo spacecraft Problem Reporting and Corrective Action System is presented. The evolution from the early system to the present day system is described. The deficiencies and the actions taken to correct them are noted, as are management controls for both the contractor and NASA. Significant experience gained from the Apollo Problem Reporting and Corrective Action System that may be applicable to future manned spacecraft is presented.

  11. A critical role for phosphatidylinositol (3,4,5)-trisphosphate-dependent Rac exchanger 1 in endothelial junction disruption and vascular hyperpermeability

    PubMed Central

    Naikawadi, Ram P.; Cheng, Ni; Vogel, Stephen M.; Qian, Feng; Wu, Dianqing; Malik, Asrar B.; Ye, Richard D.

    2013-01-01

    Rationale The small GTPase Rac is critical to vascular endothelial functions, yet its regulation in endothelial cells remains unclear. Understanding the upstream pathway may delineate Rac activation mechanisms and its role in maintaining vascular endothelial barrier integrity. Objective By investigating P-Rex1, one of the Rac-specific guanine nucleotide exchange factors (GEFs) previously known for G protein-coupled receptor (GPCR) signaling, we sought to determine whether Rac-GEF is a nodal for signal integration and potential target for drug intervention. Methods and Results Using gene deletion and siRNA silencing approach, we investigated the role of P-Rex1 in lung microvascular endothelial cells (HLMVECs). TNF-α exposure led to disruption of endothelial junctions, and silencing P-Rex1 protected junction integrity. TNF-α stimulated Rac activation and ROS production in a P-Rex1-dependent manner. Removal of P-Rex1 significantly reduced ICAM-1 expression, PMN transendothelial migration and leukocyte sequestration in TNF-α challenged mouse lungs. The P-Rex1 knockout mice were also refractory to lung vascular hyper-permeability and edema in a LPS-induced sepsis model. Conclusions These results demonstrate for the first time that P-Rex1 expressed in endothelial cells is activated downstream of TNF-α, which is not a GPCR agonist. Our data identify P-Rex1 as a critical mediator of vascular barrier disruption. Targeting P-Rex1 may effectively protect against TNF-α and LPS-induced endothelial junction disruption and vascular hyper-permeability. PMID:22965143

  12. Chemotherapy of Rodent Malaria Evaluation of Drug Action Against Normal and Resistant Strains, Including Exo-Erythrocytic Stages

    DTIC Science & Technology

    1976-12-01

    RESISTANCEI (U) CHLOROQUINE 20. iXDsrRAcT (Contrate a reverse atide ft nwce~saty and Identify by block number) Data are provided on the blood schizontocidal...litl meffeoqne uptake ofadequoine. TL synergistic action of chloroquine and erythromycin against chioroquine-resistant parasites has benfurther...Causal prophylaxis - the value of the rodent screen 3 4.3 Sustained release of drugs 4 4.4 Mode of drug action 5 4.4.1 Chloroquine and mefloquine 5

  13. 76 FR 60838 - Debarment, Suspension, and Ineligibility of Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... GOVERNMENT ACCOUNTABILITY OFFICE Debarment, Suspension, and Ineligibility of Contractors AGENCY... of government contractors. As a legislative branch agency, GAO is not subject to the requirements of... (hereinafter, contractors) who are responsible. However, GAO's Procurement Order has not explicitly referenced...

  14. 78 FR 12106 - Debarment, Suspension, and Ineligibility of Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-21

    ... OFFICE OF PERSONNEL MANAGEMENT Debarment, Suspension, and Ineligibility of Contractors AGENCY: U.S... Acquisition Regulation (FAR) regarding the debarment, suspension, and ineligibility of government contractors... ensure that it contracts only with those entities and individuals (hereinafter, contractors) who are...

  15. Immunohistochemical evalulation of activated Ras and Rac1 as potential downstream effectors of aquaporin-5 in breast cancer in vivo.

    PubMed

    Jensen, Helene H; Login, Frédéric H; Park, Ji-Young; Kwon, Tae-Hwan; Nejsum, Lene N

    2017-11-25

    Aberrant levels of aquaporin-5 (AQP5) expression have been observed in several types of cancer, including breast cancer, where AQP5 overexpression is associated with metastasis and poor prognosis. In cultured cancer cells, AQP5 facilitates cell migration and activates Ras signaling. Both increased cell migration and Ras activation are associated with cancer metastasis, but so far it is unknown if AQP5 also affects these processes in vivo. Therefore, we investigated if high AQP5 expression in breast cancer tissue correlated with increased activation of Ras and of Rac1, which is a GTPase also involved in cell migration. This was accomplished by immunohistochemical analysis of invasive ductal carcinoma of breast tissue sections from human patients, followed by qualitative and quantitative correlation analysis between AQP5 and activated Ras and Rac1. Immunohistochemistry revealed that activation of Ras and Rac1 was positively correlated. There was, however, no correlation between high AQP5 expression and activation of Ras, whereas a nonsignificant, but positive, tendency between the levels of AQP5 and activated Rac1 levels was observed. In summary, this is the first report that correlates AQP5 expression levels to downstream signaling partners in breast cancer tissue sections. The results suggest Rac1 as a potential downstream signaling partner of AQP5 in vivo. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. 44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Under 44 CFR part 351, the role of a RAC is to assist State and local government officials to develop their radiological emergency plans, to review the plans, and to observe exercises to evaluate the plans. Under subparts A and B of this part, these technical assistance activities are extended to the licensee...

  17. 44 CFR 352.23 - Functions of a Regional Assistance Committee (RAC).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Under 44 CFR part 351, the role of a RAC is to assist State and local government officials to develop their radiological emergency plans, to review the plans, and to observe exercises to evaluate the plans. Under subparts A and B of this part, these technical assistance activities are extended to the licensee...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-13

    ... GOVERNMENT ACCOUNTABILITY OFFICE Debarment, Suspension, and Ineligibility of Contractors AGENCY... government contractors. Comments on GAO's policy were due on or before November 14, 2011. GAO received two... debarment, suspension, and ineligibility of government contractors. Neither comment suggested any changes to...

  19. RIT1 controls actin dynamics via complex formation with RAC1/CDC42 and PAK1.

    PubMed

    Meyer Zum Büschenfelde, Uta; Brandenstein, Laura Isabel; von Elsner, Leonie; Flato, Kristina; Holling, Tess; Zenker, Martin; Rosenberger, Georg; Kutsche, Kerstin

    2018-05-01

    RIT1 belongs to the RAS family of small GTPases. Germline and somatic RIT1 mutations have been identified in Noonan syndrome (NS) and cancer, respectively. By using heterologous expression systems and purified recombinant proteins, we identified the p21-activated kinase 1 (PAK1) as novel direct effector of RIT1. We found RIT1 also to directly interact with the RHO GTPases CDC42 and RAC1, both of which are crucial regulators of actin dynamics upstream of PAK1. These interactions are independent of the guanine nucleotide bound to RIT1. Disease-causing RIT1 mutations enhance protein-protein interaction between RIT1 and PAK1, CDC42 or RAC1 and uncouple complex formation from serum and growth factors. We show that the RIT1-PAK1 complex regulates cytoskeletal rearrangements as expression of wild-type RIT1 and its mutant forms resulted in dissolution of stress fibers and reduction of mature paxillin-containing focal adhesions in COS7 cells. This effect was prevented by co-expression of RIT1 with dominant-negative CDC42 or RAC1 and kinase-dead PAK1. By using a transwell migration assay, we show that RIT1 wildtype and the disease-associated variants enhance cell motility. Our work demonstrates a new function for RIT1 in controlling actin dynamics via acting in a signaling module containing PAK1 and RAC1/CDC42, and highlights defects in cell adhesion and migration as possible disease mechanism underlying NS.

  20. RIT1 controls actin dynamics via complex formation with RAC1/CDC42 and PAK1

    PubMed Central

    von Elsner, Leonie; Flato, Kristina; Holling, Tess; Zenker, Martin; Rosenberger, Georg

    2018-01-01

    RIT1 belongs to the RAS family of small GTPases. Germline and somatic RIT1 mutations have been identified in Noonan syndrome (NS) and cancer, respectively. By using heterologous expression systems and purified recombinant proteins, we identified the p21-activated kinase 1 (PAK1) as novel direct effector of RIT1. We found RIT1 also to directly interact with the RHO GTPases CDC42 and RAC1, both of which are crucial regulators of actin dynamics upstream of PAK1. These interactions are independent of the guanine nucleotide bound to RIT1. Disease-causing RIT1 mutations enhance protein-protein interaction between RIT1 and PAK1, CDC42 or RAC1 and uncouple complex formation from serum and growth factors. We show that the RIT1-PAK1 complex regulates cytoskeletal rearrangements as expression of wild-type RIT1 and its mutant forms resulted in dissolution of stress fibers and reduction of mature paxillin-containing focal adhesions in COS7 cells. This effect was prevented by co-expression of RIT1 with dominant-negative CDC42 or RAC1 and kinase-dead PAK1. By using a transwell migration assay, we show that RIT1 wildtype and the disease-associated variants enhance cell motility. Our work demonstrates a new function for RIT1 in controlling actin dynamics via acting in a signaling module containing PAK1 and RAC1/CDC42, and highlights defects in cell adhesion and migration as possible disease mechanism underlying NS. PMID:29734338

  1. Private Security Contractors: The Other Force

    DTIC Science & Technology

    2011-03-22

    improving PSC oversight. This paper will not address private contractors conducting Police force training , governmental use of PSCs outside of Iraq...theater entry requirements, conduct mandatory training , conduct weapons training and qualification and conduct security verification and criminal...an effective oversight program including contractor deployment tracking, limited contract oversight personnel, and untrained Contract Officer

  2. 41 CFR 109-45.300-50 - Sales by designated contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... contractors. 109-45.300-50 Section 109-45.300-50 Public Contracts and Property Management Federal Property... § 109-45.300-50 Sales by designated contractors. Sales of surplus contractor inventory will be conducted by designated contractors when heads of field organizations determine that it is in the best interest...

  3. 48 CFR 2110.7002 - Contractor investment of FEGLI Program funds.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Contractor investment of FEGLI Program funds. (a) The Contractor is required to invest and reinvest all FEGLI... Contractor is required to credit income earned from its investment of FEGLI Program funds to the FEGLI... appropriate manner. If the Contractor fails to invest funds on hand, properly allocate investment income, or...

  4. Examples of actions that improve partnering cooperation among the participants of construction projects

    NASA Astrophysics Data System (ADS)

    Radziszewska-Zielina, E.; Szewczyk, B.

    2017-10-01

    The aim of the article is to present examples of actions that can be undertaken in order to improve partnering cooperation in construction projects. These actions are a practical supplementation to the previously developed fuzzy system of controlling partnering relations in construction projects. The actions relate to 18 parameters of partnering relations that describe cooperation between a general contractor or a company that manages the project and four other participants: the contractors (subcontractors), the designer, the material and equipment suppliers and the real estate developer. The actions have been listed based on a review of subject literature, self-analysis, as well as interviews with participants of construction projects. They can provide examples of good practices that maintain partnering cooperation at a high level. Good cooperation, in turn, translates into a better performance of the project.

  5. 48 CFR 47.305-15 - Loading responsibilities of contractors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Loading responsibilities of contractors. 47.305-15 Section 47.305-15 Federal Acquisition Regulations System FEDERAL... responsibilities of contractors. (a)(1) Contractors are responsible for loading, blocking, and bracing carload...

  6. Ground-based plasma contractor characterization

    NASA Technical Reports Server (NTRS)

    Patterson, Michael J.; Aadland, Randall S.

    1987-01-01

    Presented are recent NASA Lewis Research Center (LeRC) plasma contractor experimental results, as well as a description of the plasma contractor test facility. The operation of a 24 cm diameter plasma source with hollow cathode was investigated in the lighted-mode regime of electron current collection from 0.1 to 7.0 A. These results are compared to those obtained with a 12 cm plasma source. Full two-dimensional plasma potential profiles were constructed from emissive probe traces of the contractor plume. The experimentally measured dimensions of the plume sheaths were then compared to those theoretically predicted using a model of a spherical double sheath. Results are consistent for currents up to approximately 1.0 A. For currents above 1.0 A, substantial deviations from theory occur. These deviations are due to sheath asphericity, and possibly volume ionization in the double-sheath region.

  7. 77 FR 6676 - Office of Inspector General; Contractor Requirements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-09

    ... POSTAL SERVICE 39 CFR Part 230 Office of Inspector General; Contractor Requirements AGENCY: Postal... for contractors employed by the Office of Inspector General. The rule also emphasizes consistency in contractor selection, and clarifies the OIG's exclusive authority to set qualifications and standards for its...

  8. 41 CFR 109-40.000-50 - Applicability to contractors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... contractors. 109-40.000-50 Section 109-40.000-50 Public Contracts and Property Management Federal Property...-50 Applicability to contractors. DOE-PMR 109-40, Transportation and Traffic Management, should be applied to cost-type contractors' transportation and traffic management activities. Departure by cost-type...

  9. Recovery audits are back: tactics for tough times.

    PubMed

    Cascardo, Debra

    2010-01-01

    The Recovery Audit Contractor (RAC) Program was implemented in stages in 2009. Section 302 of the Tax Relief and Health Care Act of 2006 required full implementation no later than January 1, 2010. The first phase began in March 2009 and covered various states; the second phase began in August 2009. The Centers for Medicare & Medicaid Services is gradually implementing the RAC permanent program, and it will ultimately affect every provider in every state.

  10. 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 the...

  11. 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 the...

  12. 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 the...

  13. 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 the...

  14. 48 CFR 970.0407 - Contractor records retention.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor records retention. 970.0407 Section 970.0407 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Administrative Matters 970.0407 Contractor...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-02

    ... DEPARTMENT OF ENERGY 10 CFR Part 719 48 Parts 931, 952 and 970 RIN 1990-AA37 Contractor Legal... rulemaking (NOPR) to revise existing regulations covering contractor legal management requirements and make... relating to the DOE notice of proposed rulemaking to revise existing regulations covering contractor legal...

  16. 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... Clauses 2452.237-75 Clearance of contractor personnel. As prescribed in 2437.110(e), insert the following clause in solicitations and contracts. Clearance of Contractor Personnel (OCT 1999) (a) General. This...

  17. 48 CFR 1252.237-70 - Qualifications of contractor employees.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contractor employees. 1252.237-70 Section 1252.237-70 Federal Acquisition Regulations System DEPARTMENT OF....237-70 Qualifications of contractor employees. As prescribed in (TAR) 48 CFR 1237.110(a), insert the following clause: Qualifications of Contractor Employees (APR 2005) a. Definitions. As used in this clause...

  18. Enantioselectivity in Developmental Toxicity of rac-metalaxyl and R-metalaxyl in Zebrafish (Danio rerio) Embryo.

    PubMed

    Zhang, Yinjun; Zhang, Yi; Chen, An; Zhang, Wei; Chen, Hao; Zhang, Quan

    2016-06-01

    Enantioselectivity of chiral pesticides in environmental safety has attracted more and more attention. In this study, we evaluated the enantioselective toxicity of rac-metalaxyl and R-metalaxyl to zebrafish (Danio rerio) embryos through various malformations including pericardial edema, yolk sac edema, crooked body, and short tails. The results showed that there were significant differences in toxicity to zebrafish embryos caused by rac-metalaxyl and R-metalaxyl, and the LC50 s at 96 h are 416.41 (353.91, 499.29) mg · L(-1) and 320.650 (279.80, 363.46) mg · L(-1) , respectively. In order to explore the possible mechanism of the development defects, the genes involved in the hypothalamic-pituitary-gonadal axis (vtg1, vtg2, cyp17, cyp19a, cyp19b) and hypothalamic-pituitary-thyroid axis (dio1, dio2, nis, tg, tpo) were quantified by quantitative real-time polymerase chain reaction (qRT-PCR). The results revealed that there were no significant differences in the expression of vtg1, vtg2, cyp17, cyp19a, and cyp19b after exposure to rac-metalaxyl. However, the expression of vtg1, cyp19a, and cyp19b decreased significantly after exposure to R-metalaxyl. And likewise, rac-metalaxyl only caused the upregulation of dio2, while R-metalaxyl suppressed the expression of dio1 and tpo and induced the expression of dio2 and nis. The change of gene expression may cause the enantioselectivity in developmental toxicity in zebrafish embryo. The data provided here will be helpful for us to comprehensively understand the potential ecological risks of the currently used chiral fungicides. Chirality 28:489-494, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  19. SH3BP1-induced Rac-Wave2 pathway activation regulates cervical cancer cell migration, invasion, and chemoresistance to cisplatin.

    PubMed

    Wang, Jingjing; Feng, Yeqian; Chen, Xishan; Du, Zheng; Jiang, Shaijun; Ma, Shuyun; Zou, Wen

    2018-02-01

    Cervical cancer still remains the fourth most common cancer, affecting women worldwide with large geographic variations in cervical cancer incidence and mortality rates. SH3-domain binding protein-1 (SH3BP1) specifically inactivating Rac1 and its target Wave2 is required for cell motility, thus regarded as an essential regulator of cancer cell metastasis. However, the exact effects and molecular mechanisms of SH3BP1 in cervical cancer progression are still unknown. The present study is aimed to investigate the mechanism of SH3BP1 in regulation of cervical cancer cell metastasis and chemoresistance. In the present study, we demonstrated a high SH3BP1 expression in cervical cancer tissues; a higher SH3BP1 expression is also correlated with a shorter overall survival of patients with cervical cancer. Further, we revealed that SH3BP1 overexpression promoted the invasion, migration, and chemoresistance of cervical cancer cell through increasing Rac1 activity and Wave2 protein level. The promotive effect of SH3BP1 could be partially reversed by a Rac1 inhibitor, NSC 23766. In cisplatin-resistant cervical cancer tissues, SH3BP1, Rac1, and Wave2 mRNA expression was significantly up-regulated compared to that of the cisplatin-sensitive cervical cancer tissues. Taken together, SH3BP1/Rac1/Wave2 pathway may potentially act as an effective therapeutic target combined with traditional cisplatin-based chemotherapy for cervical cancer. © 2017 Wiley Periodicals, Inc.

  20. 75 FR 3977 - Addressing Tax Delinquency by Government Contractors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ... Contractors #0; #0; #0; Presidential Documents #0; #0; #0;#0;Federal Register / Vol. 75, No. 15 / Monday... of January 20, 2010 Addressing Tax Delinquency by Government Contractors Memorandum for the Heads of... contractors and has an important obligation to protect American taxpayer money and the integrity of the...

  1. 76 FR 81408 - Contractor Legal Management Requirements; Acquisition Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-28

    ... DEPARTMENT OF ENERGY 10 CFR Part 719 48 CFR Parts 931, 952 and 970 RIN 1990-AA37 Contractor Legal... Energy (DOE or Department) is proposing to revise existing regulations covering contractor legal... costs by certain contractors whose contracts exceed $100,000,000 as well as legal counsel retained...

  2. 48 CFR 52.236-6 - Superintendence by the Contractor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Contractor. 52.236-6 Section 52.236-6 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION....236-6 Superintendence by the Contractor. As prescribed in 36.506, insert the following clause: Superintendence by the Contractor (APR 1984) At all times during performance of this contract and until the work...

  3. Timing is everything: Rac1 controls Net1A localization to regulate cell adhesion.

    PubMed

    Carr, Heather S; Frost, Jeffrey A

    2013-01-01

    Cell adhesion to the extracellular matrix elicits a temporal reorganization of the actin cytoskeleton that is regulated first by Rac1 and later by RhoA. The signaling mechanisms controlling late stage RhoA activation are incompletely understood. Net1A is a RhoA/RhoB-specific guanine nucleotide exchange factor that is required for cancer cell motility. The ability of Net1A to stimulate RhoA activation is negatively regulated by nuclear sequestration. However, mechanisms controlling the plasma membrane localization of Net1A had not previously been reported. Recently we have shown that Rac1 activation stimulates plasma membrane relocalization and activation of Net1A. Net1A relocalization is independent of its catalytic activity and does not require its C-terminal pleckstrin homology or PDZ interacting domains. Rac1 activation during cell adhesion stimulates a transient relocalization of Net1A that is terminated by proteasomal degradation of Net1A. Importantly, plasma membrane localization of Net1A is required for efficient myosin light chain phosphorylation, focal adhesion maturation, and cell spreading. These data show for the first time a physiological mechanism controlling Net1A relocalization from the nucleus. They also demonstrate a previously unrecognized role for Net1A in controlling actomyosin contractility and focal adhesion dynamics during cell adhesion.

  4. 48 CFR 752.7013 - Contractor-mission relationships.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....7013 Contractor-mission relationships. For use in all USAID contracts involving performance overseas... contract, and for advising USAID regarding the performance of the work under the contract and its effect on... of academic freedom. Notwithstanding these academic freedoms, the Contractor's employees, while in...

  5. ArhGAP15, a Rac-specific GTPase-activating Protein, Plays a Dual Role in Inhibiting Small GTPase Signaling*

    PubMed Central

    Radu, Maria; Rawat, Sonali J.; Beeser, Alexander; Iliuk, Anton; Tao, Weiguo Andy; Chernoff, Jonathan

    2013-01-01

    Signaling from small GTPases is a tightly regulated process. In this work we used a protein microarray screen to identify the Rac-specific GAP, ArhGAP15, as a substrate of the Rac effectors Pak1 and Pak2. In addition to serving as a substrate of Pak1/2, we found that ArhGAP15, via its PH domain, bound to these kinases. The association of ArhGAP15 to Pak1/2 resulted in mutual inhibition of GAP and kinase catalytic activity, respectively. Knock-down of ArhGAP15 resulted in activation of Pak1/2, both indirectly, as a result of Rac activation, and directly, as a result of disruption of the ArhGAP15/Pak complex. Our data suggest that ArhGAP15 plays a dual negative role in regulating small GTPase signaling, by acting at the level of the GTPase itself, as well interacting with its effector, Pak kinase. PMID:23760270

  6. 76 FR 31416 - Federal Acquisition Regulation; Oversight of Contractor Ethics Programs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ...-AL92 Federal Acquisition Regulation; Oversight of Contractor Ethics Programs AGENCY: Department of... that contractors have implemented the mandatory contractor business ethics program requirements. DATES... to Improve DoD's Oversight of Contractor Ethics Programs. The ethics program requirement flows from...

  7. 14-3-3 coordinates microtubules, Rac, and myosin II to control cell mechanics and cytokinesis

    PubMed Central

    Zhou, Qiongqiong; Kee, Yee-Seir; Poirier, Christopher C.; Jelinek, Christine; Osborne, Jonathan; Divi, Srikanth; Surcel, Alexandra; Will, Marie E.; Eggert, Ulrike S.; Müller-Taubenberger, Annette; Iglesias, Pablo A.; Cotter, Robert J.; Robinson, Douglas N.

    2010-01-01

    Summary Background During cytokinesis, regulatory signals are presumed to emanate from the mitotic spindle. However, what these signals are and how they lead to the spatiotemporal changes in the cortex structure, mechanics, and regional contractility are not well understood in any system. Results To investigate pathways that link the microtubule network to the cortical changes that promote cytokinesis, we used chemical genetics in Dictyostelium to identify genetic suppressors of nocodazole, a microtubule depolymerizer. We identified 14-3-3 and found that it is enriched in the cortex, helps maintain steady state microtubule length, contributes to normal cortical tension, modulates actin wave formation, and controls the symmetry and kinetics of cleavage furrow contractility during cytokinesis. Furthermore, 14-3-3 acts downstream of a Rac small GTPase (RacE), associates with myosin II heavy chain and is needed to promote myosin II bipolar thick filament remodeling. Conclusion 14-3-3 connects microtubules, Rac and myosin II to control several aspects of cortical dynamics, mechanics, and cytokinesis cell shape change. Further, 14-3-3 interacts directly with myosin II heavy chain to promote bipolar thick filament remodeling and distribution. Overall, 14-3-3 appears to integrate several critical cytoskeletal elements that drive two important processes cytokinesis shape change and cell mechanics. PMID:20951045

  8. Mangiferin inhibits cell migration and invasion through Rac1/WAVE2 signalling in breast cancer.

    PubMed

    Deng, Qing; Tian, Yan-Xiao; Liang, JianJun

    2018-04-01

    Breast tumour progression results from the advancement of the disease to a metastatic phenotype. Rac1 and Cdc42 belong to the Rho family of genes that, together with their downstream effectors, Wiskott-Aldrich Syndrome protein-family verprolin-homologous protein 2 (WAVE2) and Arp2/3, assume a vital part in cytoskeletal rearrangement and the arrangement of film projections that advance malignant cell relocation and invasion. Mangiferin is a characteristic polyphenolic compound from Mangifera indica L. (Anacardiaceae), ordinarily referred to as mango, that is consumed worldwide as a natural product, including culinary and seasoning applications. Mangiferin delays breast malignancy development and progression by inhibiting different signalling pathways required in mitogenic signalling and metastatic progression. Studies were performed to analyse the impact of mangiferin on Rac1/WAVE2 flagging, relocation and invasion in highly metastatic human MDA-MB-231 mammary cells. Additional studies led to the observation that comparative treatment with mangiferin caused marked reduction in tumour cell movement and invasion. Taken together, these discoveries demonstrate that mangiferin treatment adequately hinders Rac1/WAVE2 flagging and diminishes metastatic phenotypic expression in malignant mammary cells, indicating that mangiferin may provide a benefit as a novel restorative approach in the treatment of metastatic breast cancer.

  9. 48 CFR 227.7108 - Contractor data repositories.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Technical Data 227.7108 Contractor data repositories. (a) Contractor data repositories may be established... procedures for protecting technical data delivered to or stored at the repository from unauthorized release... disclosure of technical data from the repository to third parties consistent with the Government's rights in...

  10. 48 CFR 1437.7001 - Contractor qualification requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor qualification requirements. 1437.7001 Section 1437.7001 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR... Contractor qualification requirements. (a) Prior to award of a contract for real property appraisal services...

  11. Deletion of Wiskott–Aldrich syndrome protein triggers Rac2 activity and increased cross-presentation by dendritic cells

    PubMed Central

    Baptista, Marisa A. P.; Keszei, Marton; Oliveira, Mariana; Sunahara, Karen K. S.; Andersson, John; Dahlberg, Carin I. M.; Worth, Austen J.; Liedén, Agne; Kuo, I-Chun; Wallin, Robert P. A.; Snapper, Scott B.; Eidsmo, Liv; Scheynius, Annika; Karlsson, Mikael C. I.; Bouma, Gerben; Burns, Siobhan O.; Forsell, Mattias N. E.; Thrasher, Adrian J.; Nylén, Susanne; Westerberg, Lisa S.

    2016-01-01

    Wiskott–Aldrich syndrome (WAS) is caused by loss-of-function mutations in the WASp gene. Decreased cellular responses in WASp-deficient cells have been interpreted to mean that WASp directly regulates these responses in WASp-sufficient cells. Here, we identify an exception to this concept and show that WASp-deficient dendritic cells have increased activation of Rac2 that support cross-presentation to CD8+ T cells. Using two different skin pathology models, WASp-deficient mice show an accumulation of dendritic cells in the skin and increased expansion of IFNγ-producing CD8+ T cells in the draining lymph node and spleen. Specific deletion of WASp in dendritic cells leads to marked expansion of CD8+ T cells at the expense of CD4+ T cells. WASp-deficient dendritic cells induce increased cross-presentation to CD8+ T cells by activating Rac2 that maintains a near neutral pH of phagosomes. Our data reveals an intricate balance between activation of WASp and Rac2 signalling pathways in dendritic cells. PMID:27425374

  12. A family affair: A Ral-exocyst-centered network links Ras, Rac, Rho signaling to control cell migration.

    PubMed

    Zago, Giulia; Biondini, Marco; Camonis, Jacques; Parrini, Maria Carla

    2017-05-12

    Cell migration is central to many developmental, physiologic and pathological processes, including cancer progression. The Ral GTPases (RalA and RalB) which act down-stream the Ras oncogenes, are key players in the coordination between membrane trafficking and actin polymerization. A major direct effector of Ral, the exocyst complex, works in polarized exocytosis and is at the center of multiple protein-protein interactions that support cell migration by promoting protrusion formation, front-rear polarization, and extra-cellular matrix degradation. In this review we describe the recent advancements in deciphering the molecular mechanisms underlying this role of Ral via exocyst on cell migration. Among others, we will discuss the recently identified cross-talk between Ral and Rac1 pathways: exocyst binds to a negative regulator (the RacGAP SH3BP1) and to the major effector (the Wave Regulatory Complex, WRC) of Rac1, the master regulator of protrusions. Next challenge will be to better characterize the dynamics in space and in time of these molecular interplays, to better understand the pleiotropic functions of Ral in both normal and cancer cells.

  13. Programmed Application of Transforming Growth Factor β3 and Rac1 Inhibitor NSC23766 Committed Hyaline Cartilage Differentiation of Adipose-Derived Stem Cells for Osteochondral Defect Repair.

    PubMed

    Zhu, Shouan; Chen, Pengfei; Wu, Yan; Xiong, Si; Sun, Heng; Xia, Qingqing; Shi, Libing; Liu, Huanhuan; Ouyang, Hong Wei

    2014-10-01

    Hyaline cartilage differentiation is always the challenge with application of stem cells for joint repair. Transforming growth factors (TGFs) and bone morphogenetic proteins can initiate cartilage differentiation but often lead to hypertrophy and calcification, related to abnormal Rac1 activity. In this study, we developed a strategy of programmed application of TGFβ3 and Rac1 inhibitor NSC23766 to commit the hyaline cartilage differentiation of adipose-derived stem cells (ADSCs) for joint cartilage repair. ADSCs were isolated and cultured in a micromass and pellet culture model to evaluate chondrogenic and hypertrophic differentiation. The function of Rac1 was investigated with constitutively active Rac1 mutant and dominant negative Rac1 mutant. The efficacy of ADSCs with programmed application of TGFβ3 and Rac1 inhibitor for cartilage repair was studied in a rat model of osteochondral defects. The results showed that TGFβ3 promoted ADSCs chondro-lineage differentiation and that NSC23766 prevented ADSC-derived chondrocytes from hypertrophy in vitro. The combination of ADSCs, TGFβ3, and NSC23766 promoted quality osteochondral defect repair in rats with much less chondrocytes hypertrophy and significantly higher International Cartilage Repair Society macroscopic and microscopic scores. The findings have illustrated that programmed application of TGFβ3 and Rac1 inhibitor NSC23766 can commit ADSCs to chondro-lineage differentiation and improve the efficacy of ADSCs for cartilage defect repair. These findings suggest a promising stem cell-based strategy for articular cartilage repair. ©AlphaMed Press.

  14. Battlefield Contractors: Operational Risk and System Support Contractors

    DTIC Science & Technology

    2010-10-27

    incentive for the use of contractors is the proven cost savings when compared to similarly trained active duty military forces. The Office of...no military or government civilian is trained to do. The reality is that “modern military operations now depend heavily on high-tech weapons systems...squadrons that rely exclusively on contracted line maintenance, with no military personnel trained to support the aircraft. Defense supplemental funds

  15. 21 CFR 20.90 - Disclosure to contractors.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... INFORMATION Limitations on Exemptions § 20.90 Disclosure to contractors. (a) Data and information otherwise... of such data and information as Food and Drug Administration employees. (b) A written agreement between the Food and Drug Administration and any contractor shall be entered into before data and...

  16. 21 CFR 20.90 - Disclosure to contractors.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... INFORMATION Limitations on Exemptions § 20.90 Disclosure to contractors. (a) Data and information otherwise... of such data and information as Food and Drug Administration employees. (b) A written agreement between the Food and Drug Administration and any contractor shall be entered into before data and...

  17. 48 CFR 1646.301 - Contractor inspection requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor inspection requirements. 1646.301 Section 1646.301 Federal Acquisition Regulations System OFFICE OF PERSONNEL MANAGEMENT... Clauses 1646.301 Contractor inspection requirements. The clause set forth at 1652.246-70 shall be inserted...

  18. 14 CFR 1274.402 - Contractor acquired property.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Contractor acquired property. 1274.402 Section 1274.402 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION COOPERATIVE AGREEMENTS WITH COMMERCIAL FIRMS Property § 1274.402 Contractor acquired property. As provided in § 1274.923...

  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. Transformative Learning: Immigrant Learners Who Participated in Recognition of Acquired Competencies (RAC)

    ERIC Educational Resources Information Center

    Moss, Leah; Brown, Andy

    2014-01-01

    Recognition of Acquired Competencies (RAC) as it is known in Quebec, Canada, or Prior Learning Assessment (PLA), requires a learner to engage in retrospective thought about their learning path, their learning style and their experiential knowledge. This process of critical self-reflection and rigorous analysis by the learner of their prior…