Selective sorting of alpha-granule proteins

Authors


Joseph E. Italiano Jr., Translational Medicine Division, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA 02115, USA.
Tel.: +1 617 355 9007; fax: +1 67 355 9016.
E-mail: jitaliano@rics.bwh.harvard.edu

Abstract

Summary.  One of the main functions of blood platelets is to secrete a variety of substances that can modify a developing thrombus, regulate the growth of the vasculature, promote wound repair, and contribute to cell-adhesive events. A majority of this vast array of secreted proteins are stored in alpha-granules. Until recently, it was assumed that platelets contained one homogeneous population of alpha-granules that undergo complete de-granulation during platelet activation. This review focuses on the mechanisms of alpha-granule biogenesis and secretion, with a particular emphasis on recent findings that clearly demonstrate that platelets contain distinct subpopulations of alpha-granules that undergo differential release during activation. We consider the implications of this new paradigm of platelet secretion, discuss mechanisms of alpha-granule biogenesis, and review the molecular basis of transport and delivery of alpha-granules to assembling platelets.

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