title: Activation-dependent redistribution of the adhesion plaque protein, talin, in intact human platelets.
abstract: Talin is a high molecular weight protein localized at adhesion plaques in fibroblasts. It binds vinculin and integrin and appears to participate in generating a transmembrane connection between the extracellular matrix and the cytoskeleton. We have recently shown that talin is an abundant protein in platelets, cells highly specialized for regulated adhesion. Although talin constitutes greater than 3% of the total protein in intact human platelets, its location within the cells had not been defined. In the work reported here, we have investigated the distribution of talin in resting and activated human platelets by immunofluorescence and immunoelectron microscopy. We have found that talin undergoes an activation-dependent change in its subcellular location. In resting platelets, which are nonadhesive, talin is uniformly distributed throughout the cytoplasm. In contrast, in thrombin- and glass-activated, substratum-adherent platelets, talin is concentrated at the cytoplasmic face of the plasma membrane. This dramatic, regulated redistribution of talin raises the possibility that talin plays a role in the controlled development of platelet adhesion.
authors.affiliation: Department of Biology, University of Utah, Salt Lake City 84112.
authors.forename: M C
authors.initials: MC
authors.lastname: Beckerle
authors.forename: D E
authors.initials: DE
authors.lastname: Miller
authors.forename: M E
authors.initials: ME
authors.lastname: Bertagnolli
authors.forename: S J
authors.initials: SJ
authors.lastname: Locke
mesh_terms: D001792:Blood Platelets / Q000378:metabolism* / Q000648:ultrastructure; D002118:Calcium / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000276:immunology / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007158:Immunologic Techniques; D066298:In Vitro Techniques; D010447:Peptide Hydrolases; D015539:Platelet Activation; D010973:Platelet Adhesiveness / Q000502:physiology*; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D016608:Talin; D013917:Thrombin
chemical_list: D003598:Cytoskeletal Proteins; D010980:Platelet Membrane Glycoproteins; D016608:Talin; D010447:Peptide Hydrolases; D013917:Thrombin; D002118:Calcium