Research article

Studies on the actin-binding protein HS1 in platelets

Steven G Thomas^1,2 , Simon DJ Calaminus² , Jocelyn M Auger² , Stephen P Watson² and Laura M Machesky¹

¹School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK

²Centre for Cardiovascular Sciences, Institute of Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK

author email corresponding author email

BMC Cell Biology 2007, 8:46doi:10.1186/1471-2121-8-46

Published:	9 November 2007

Abstract

Background

The platelet cytoskeleton mediates the dramatic change in platelet morphology that takes place upon activation and stabilizes thrombus formation. The Arp2/3 complex plays a vital role in these processes, providing the protrusive force for lamellipodia formation. The Arp2/3 complex is highly regulated by a number of actin-binding proteins including the haematopoietic-specific protein HS1 and its homologue cortactin. The present study investigates the role of HS1 in platelets using HS1^-/- mice.

Results

The present results demonstrate that HS1 is not required for platelet activation, shape change or aggregation. Platelets from HS1^-/- mice spread normally on a variety of adhesion proteins and have normal F-actin and Arp2/3 complex distributions. Clot retraction, an actin-dependent process, is also normal in these mice. Platelet aggregation and secretion is indistinguishable between knock out and littermates and there is no increase in bleeding using the tail bleeding assay.

Conclusion

This study concludes that HS1 does not play a major role in platelet function. It is possible that a role for HS1 is masked by the presence of cortactin.