Lighting up kinase action in platelets

Abstract

Platelet functions are highly regulated by signaling networks involving at least 300 protein kinases [2]. Platelets express members of the mitogen-activated protein kinase (MAPK) family including p42 ERK2 and, at lower concentrations, p44 ERK1. Both ERK isoforms are activated by agonists like von Willebrand factor, collagen, thrombin, ADP and thromboxane A2 [3-7]. ERK activation depends on MAPK kinase (MKK-1 or MEK) and involves Gq, Gi, phospholipase C and Src family kinase signaling [5, 8]. Active ERK has been shown to stimulate thromboxane A2 production [5] and to contribute to platelet aggregation [4, 9]. Downstream substrates of ERK have not been identified in platelets so far. This article is protected by copyright. All rights reserved.