Talin is required for integrin-mediated platelet function in hemostasis and thrombosis

Integrins are critical for hemostasis and thrombosis because they mediate both platelet adhesion and aggregation. Talin is an integrin-binding cytoplasmic adaptor that is a central organizer of focal adhesions, and loss of talin phenocopies integrin deletion in Drosophila. Here, we have examined the...

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Published in:	The Journal of experimental medicine Vol. 204; no. 13; pp. 3103 - 3111
Main Authors:	Petrich, Brian G, Marchese, Patrizia, Ruggeri, Zaverio M, Spiess, Saskia, Weichert, Rachel A M, Ye, Feng, Tiedt, Ralph, Skoda, Radek C, Monkley, Susan J, Critchley, David R, Ginsberg, Mark H
Format:	Journal Article
Language:	English
Published:	United States The Rockefeller University Press 24-12-2007
Subjects:	Animals Blood Platelets - metabolism Brief Definitive Reports Drosophila Female Gene Deletion Hemostasis Homozygote Integrin alpha2beta1 - metabolism Integrin beta1 - metabolism Integrin beta3 - metabolism Integrins - metabolism Male Mice Mice, Inbred C57BL Platelet Aggregation Platelet Glycoprotein GPIIb-IIIa Complex - metabolism Platelet Membrane Glycoprotein IIb - biosynthesis Talin - physiology Thrombosis
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Summary:	Integrins are critical for hemostasis and thrombosis because they mediate both platelet adhesion and aggregation. Talin is an integrin-binding cytoplasmic adaptor that is a central organizer of focal adhesions, and loss of talin phenocopies integrin deletion in Drosophila. Here, we have examined the role of talin in mammalian integrin function in vivo by selectively disrupting the talin1 gene in mouse platelet precursor megakaryocytes. Talin null megakaryocytes produced circulating platelets that exhibited normal morphology yet manifested profoundly impaired hemostatic function. Specifically, platelet-specific deletion of talin1 led to spontaneous hemorrhage and pathological bleeding. Ex vivo and in vitro studies revealed that loss of talin1 resulted in dramatically impaired integrin alphaIIbbeta3-mediated platelet aggregation and beta1 integrin-mediated platelet adhesion. Furthermore, loss of talin1 strongly inhibited the activation of platelet beta1 and beta3 integrins in response to platelet agonists. These data establish that platelet talin plays a crucial role in hemostasis and provide the first proof that talin is required for the activation and function of mammalian alpha2beta1 and alphaIIbbeta3 integrins in vivo.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 CORRESPONDENCE Mark H. Ginsberg: mhginsberg@ucsd.edu
ISSN:	0022-1007 1540-9538 1892-1007
DOI:	10.1084/jem.20071800