Referenced in: none

Automatically associated channels: Kv10.1

Title: Glycoprotein Ib cross-linking/ligation on echicetin-coated surfaces or echicetin-IgMkappa in stirred suspension activates platelets by cytoskeleton modulated calcium release.

Authors: Alexey Navdaev, Kenneth J Clemetson

Journal, date & volume: J. Biol. Chem., 2002 Nov 29 , 277, 45928-34

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/12324454

Abstract
Cross-linking platelet GPIb with the snake C-type lectin echicetin provides a specific technique for activation via this receptor. This allows GPIb-dependent mechanisms to be studied without the necessity for shear stress-induced binding of von Willebrand factor or primary alpha(IIb)beta(3) involvement. We already showed that platelets are activated, including tyrosine phosphorylation, by echicetin-IgMkappa-induced GPIb cross-linking. We now investigate the mechanism further and demonstrate that platelets, without modulator reagents, spread directly on an echicetin-coated surface, by a GPIb-specific mechanism, causing exocytosis of alpha-granule markers (P-selectin) and activation of alpha(IIb)beta(3). This spreading requires actin polymerization and release of internal calcium stores but is not dependent on external calcium nor on src family tyrosine kinases. Cross-linking of GPIb complex molecules on platelets, either in suspension or via specific surface attachment, is sufficient to induce platelet activation.