Continued support is requested for a program to analyze activation of integrin allbB3, a process central to normal hemostasis and to arterial thrombosis. The applicant has developed approaches for analyzing intracellular integrin signaling, identified protein-protein interactions at the integrin cytoplasmic face, and provided structural insight into some of those interactions. His studies proved that talin binding to the integrin B cytoplasmic domain is a final step in activation, provided insights into how talin activates integrins, showed how Rapl cooperates with talin to activate integrins, and validated the anti-thrombotic potential of interfering with the talin-B3 integrin interaction. He will now test the hypothesis that talin and/or kindlin binding to integrin allbB3 is sufficient for activation by reconstituting integrin allbB3 into lipid bilayers and examining the capacity of purified proteins to activate the integrin. He will test the hypothesis that RIAM contains a Rap1-regulated talin binding site and that RIAM uncovers talin's integrin binding by studying fragment of RIAM, and the Rap dependence of their interactions with each other and with talin. In addition he will assess the ability of talin-binding fragments of RIAM to cooperate with talin to induce integrin activation in cells and will use bimolecular fluorescence complementation to assess the capacity of these RIAM fragments to promote the integrin-talin interaction.
A third aim will test the hypothesis that interactions of the a and B transmembrane domains regulate integrin activation by analyzing the interactions of these transmembrane domains in mammalian cell membranes and in lipid bicelles. He will test the hypothesis that talin-induced integrin activation plays a distinct role from talin-mediated linkage of integrins to the cytoskeleton in leukocyte and platelet function in vivo by creating mice that either lack wild type talin in platelets and leukocytes and that express talin mutants that maintain the ability to bind to integrins and cytoplasmic partners such as vinculin, but cannot activate integrins. He will assess platelet and leukocyte function in these animals in collaborations with Drs. Ruggeri, Groisman, and Ley. These fundamental studies will provide novel insight into the regulation of platelet aggregation and will test and advance paradigms that apply to many integrin-dependent biological processes.

Public Health Relevance

Platelet aggregation is required for normal hemostasis and is the proximate cause of arterial thrombosis, the leading cause of heart attack and stroke. Activation of platelet GPIIb-llla (integrin allbB3) is a critical process that controls platelet aggregation. The present studies will continue to elucidate the mechanisms and consequences of activation of GPIIb-llla and may therefore lead to new therapeutic approaches to thrombosis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL078784-09
Application #
8476250
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
9
Fiscal Year
2013
Total Cost
$360,627
Indirect Cost
$71,062
Name
University of California San Diego
Department
Type
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Klann, Jane E; Kim, Stephanie H; Remedios, Kelly A et al. (2018) Integrin Activation Controls Regulatory T Cell-Mediated Peripheral Tolerance. J Immunol 200:4012-4023
Weijts, Bart; Gutierrez, Edgar; Saikin, Semion K et al. (2018) Blood flow-induced Notch activation and endothelial migration enable vascular remodeling in zebrafish embryos. Nat Commun 9:5314
Sun, Hao; Lagarrigue, Frederic; Gingras, Alexandre R et al. (2018) Transmission of integrin ?7 transmembrane domain topology enables gut lymphoid tissue development. J Cell Biol 217:1453-1465
Marki, Alex; Buscher, Konrad; Mikulski, Zbigniew et al. (2018) Rolling neutrophils form tethers and slings under physiologic conditions in vivo. J Leukoc Biol 103:67-70
Moccetti, Federico; Brown, Eran; Xie, Aris et al. (2018) Myocardial Infarction Produces Sustained Proinflammatory Endothelial Activation in Remote Arteries. J Am Coll Cardiol 72:1015-1026
Lagarrigue, Frederic; Gingras, Alexandre R; Paul, David S et al. (2018) Rap1 binding to the talin 1 F0 domain makes a minimal contribution to murine platelet GPIIb-IIIa activation. Blood Adv 2:2358-2368
Wolf, Dennis; Anto-Michel, Nathaly; Blankenbach, Hermann et al. (2018) A ligand-specific blockade of the integrin Mac-1 selectively targets pathologic inflammation while maintaining protective host-defense. Nat Commun 9:525
Lopez-Ramirez, Miguel Alejandro; Fonseca, Gregory; Zeineddine, Hussein A et al. (2017) Thrombospondin1 (TSP1) replacement prevents cerebral cavernous malformations. J Exp Med 214:3331-3346
Ye, Feng; Yang, Chansik; Kim, Jiyoon et al. (2017) Epigallocatechin gallate has pleiotropic effects on transmembrane signaling by altering the embedding of transmembrane domains. J Biol Chem 292:9858-9864
Rothmeier, Andrea S; Marchese, Patrizia; Langer, Florian et al. (2017) Tissue Factor Prothrombotic Activity Is Regulated by Integrin-arf6 Trafficking. Arterioscler Thromb Vasc Biol 37:1323-1331

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