Journal of Cell Science, Vol 106, Issue 4 1189-1199, Copyright © 1993 by Company of Biologists

JOURNAL ARTICLES

Talin distribution and phosphorylation in thrombin-activated platelets

ME Bertagnolli, SJ Locke, ME Hensler, PF Bray and MC Beckerle
Department of Biology, University of Utah, Salt Lake City 84112.

We have previously demonstrated that the subcellular distribution of the adhesion plaque protein, talin, changes dramatically in human platelets in response to platelet activation (Beckerle et al., J. Cell Biol. 109, 3333-3346, 1989). Talin is uniformly distributed throughout the cytoplasm of resting platelets. However, when platelets are stimulated to become activated and adhesive, a significant amount of the talin population rapidly redistributes to a peripheral, submembranous location. In the present study we have examined talin phosphorylation and proteolytic cleavage as possible mechanisms by which talin's subcellular distribution could be regulated in platelets. We have found that thrombin activation of platelets leads to a fourfold increase in talin phosphorylation. Proteolytic cleavage of talin, however, is not detected in washed platelets activated with thrombin for as long as 30 minutes. Because talin moves to a submembranous location upon platelet activation and has been shown to interact with integrins in vitro, we also investigated whether the major platelet integrin, GPIIb-IIIa, is required for talin redistribution. Using Glanzmann thrombasthenic platelets, which are deficient in GPIIb-IIIa, we found that talin redistribution occurs even in the absence of GPIIb-IIIa. Collectively, our studies suggest that neither proteolytic cleavage of talin nor interactions between talin and GPIIb-IIIa is required for the regulated redistribution of talin in thrombin-activated platelets. Phosphorylation of talin in response to thrombin activation may, however, be one mechanism utilized by platelets to regulate talin distribution and function in human platelets.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				N. Watanabe, L. Bodin, M. Pandey, M. Krause, S. Coughlin, V. A. Boussiotis, M. H. Ginsberg, and S. J. Shattil Mechanisms and consequences of agonist-induced talin recruitment to platelet integrin {alpha}IIb{beta}3 J. Cell Biol., October 22, 2008; 181(7): 1211 - 1222. [Abstract] [Full Text] [PDF]

				B. Nguyen, M. E. Carbajal, and M. L. Vitale Intracellular Mechanisms Involved in Dopamine-Induced Actin Cytoskeleton Organization and Maintenance of a Round Phenotype in Cultured Rat Lactotrope Cells Endocrinology, August 1, 1999; 140(8): 3467 - 3477. [Abstract] [Full Text]

				M. L. Borowsky and R. O. Hynes Layilin, A Novel Talin-binding Transmembrane Protein Homologous with C-type Lectins, is Localized in Membrane Ruffles J. Cell Biol., October 19, 1998; 143(2): 429 - 442. [Abstract] [Full Text] [PDF]

				K. L. Schaphorst, F. M. Pavalko, C. E. Patterson, and J. G. N. Garcia Thrombin-mediated Focal Adhesion Plaque Reorganization in Endothelium: Role of Protein Phosphorylation Am. J. Respir. Cell Mol. Biol., October 1, 1997; 17(4): 443 - 455. [Abstract] [Full Text]

				I. Knezevic, T. M. Leisner, and S. C.-T. Lam Direct Binding of the Platelet Integrin alpha IIbbeta 3 (GPIIb-IIIa) to Talin. EVIDENCE THAT INTERACTION IS MEDIATED THROUGH THE CYTOPLASMIC DOMAINS OF BOTH alpha IIb AND beta 3 J. Biol. Chem., July 5, 1996; 271(27): 16416 - 16421. [Abstract] [Full Text] [PDF]

				L Hemmings, D. Rees, V Ohanian, S. Bolton, A. Gilmore, B Patel, H Priddle, J. Trevithick, R. Hynes, and D. Critchley Talin contains three actin-binding sites each of which is adjacent to a vinculin-binding site J. Cell Sci., January 11, 1996; 109(11): 2715 - 2726. [Abstract] [PDF]

				C Albiges-Rizo, P Frachet, and M. Block Down regulation of talin alters cell adhesion and the processing of the alpha 5 beta 1 integrin J. Cell Sci., January 10, 1995; 108(10): 3317 - 3329. [Abstract] [PDF]