Continued support is requested for studies to analyze suppression of integrin activation, a process central to the control of blood and vascular cell migration and to platelet aggregation. The applicant found that activation of H-Ras GTPase leads to suppression of integrin activation through the activation of ERK1/2 at the plasma membrane. The discovery that talin binding to the integrin ]3 cytoplasmic domain is a final step in integrin activation enabled him to partially reconstruct integrin activation in a nucleated cell and ordered the pathway as Agonist ->PKC ->Rap ->Talin ->lntegrin. He proposes to test the hypothesis that Rap1 activates integrins by stimulating the interaction of talin with the integrin /? cytoplasmic domain through a Rap1 effector and that ERK1/2 blocks activation by regulating one or more of the elements in this pathway. He will further reconstruct agonist-mediated integrin orllb/?3 activation in CHO cells through the introduction of talin and other signaling molecules (e.g. Protein kinase C, R-Ras, Rap 1). He will use the reconstructed system to order the participants and to establish the step(s) at which Rap1 and ERK 1/2 regulate integrin ollb/?3 activation. Secondly, he found that PEA-15 regulates integrin activation and cell proliferation by binding to ERK1/2 and that PEA-15 is expressed in endothelial cells and arterial smooth muscle cells. He will test the hypothesis that PEA-15 expression and/or phosphorylation regulates the proliferation and survival of endothelial cells and smooth muscle cells in vitro and in vivo. This will be done by examining the role of PEA-15 in regulating tumor cell invasion, angiogenesis and re-stenosis and in endothelial cell and smooth muscle cell proliferation in vitro. Finally, the small GTPase, R-Ras, reverses suppression of integrin activation and stimulates cell spreading via an apparently novel effector. By use of a TAP-tagged R-Ras and high throughput proteomics, he developed an experimental database of candidate R-Ras interacting proteins and found that RLIP76 had the properties expected of an effector that regulates integrin function. He will test the hypothesis that RLIP76 is an R-Ras effector that mediates adhesion-dependent cell signaling by Use of siRNA-mediated knockdown and structure-function analysis of RLIP76. These studies will provide fundamental insights into pathways that control the activation of integrins in cells of the blood and vasculature and may serve to identify novel therapeutic targets for diseases of hemostasis and thrombosis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL057900-15
Application #
8213149
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
2011-02-01
Budget End
2012-01-31
Support Year
15
Fiscal Year
2011
Total Cost
$303,542
Indirect Cost
Name
University of California San Diego
Department
Type
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Wilson, RaeAnna; Espinosa-Diez, Cristina; Kanner, Nathan et al. (2016) MicroRNA regulation of endothelial TREX1 reprograms the tumour microenvironment. Nat Commun 7:13597
Liao, Zhongji; Kato, Hisashi; Pandey, Manjula et al. (2015) Interaction of kindlin-2 with integrin ?3 promotes outside-in signaling responses by the ?V?3 vitronectin receptor. Blood 125:1995-2004
Desgrosellier, Jay S; Lesperance, Jacqueline; Seguin, Laetitia et al. (2014) Integrin ?v?3 drives slug activation and stemness in the pregnant and neoplastic mammary gland. Dev Cell 30:295-308
Fitzpatrick, Paul; Shattil, Sanford J; Ablooglu, Ararat J (2014) C-terminal COOH of integrin ?1 is necessary for ?1 association with the kindlin-2 adapter protein. J Biol Chem 289:11183-93
Seguin, Laetitia; Kato, Shumei; Franovic, Aleksandra et al. (2014) An integrin ??-KRAS-RalB complex drives tumour stemness and resistance to EGFR inhibition. Nat Cell Biol 16:457-68
Casar, B; Rimann, I; Kato, H et al. (2014) In vivo cleaved CDCP1 promotes early tumor dissemination via complexing with activated ?1 integrin and induction of FAK/PI3K/Akt motility signaling. Oncogene 33:255-68
Ye, Feng; Petrich, Brian G; Anekal, Praju et al. (2013) The mechanism of kindlin-mediated activation of integrin ?IIb?3. Curr Biol 23:2288-2295
Banno, Asoka; Goult, Benjamin T; Lee, HoSup et al. (2012) Subcellular localization of talin is regulated by inter-domain interactions. J Biol Chem 287:13799-812
Kim, Chungho; Schmidt, Thomas; Cho, Eun-Gyung et al. (2012) Basic amino-acid side chains regulate transmembrane integrin signalling. Nature 481:209-13
Ye, Feng; Kim, Chungho; Ginsberg, Mark H (2012) Reconstruction of integrin activation. Blood 119:26-33

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