First Author | Stritt S | Year | 2015 |
Journal | Blood | Volume | 125 |
Issue | 2 | Pages | 219-22 |
PubMed ID | 25336629 | Mgi Jnum | J:220786 |
Mgi Id | MGI:5636131 | Doi | 10.1182/blood-2014-08-597542 |
Citation | Stritt S, et al. (2015) Rap1-GTP-interacting adaptor molecule (RIAM) is dispensable for platelet integrin activation and function in mice. Blood 125(2):219-22 |
abstractText | Platelet aggregation at sites of vascular injury is essential for hemostasis but also thrombosis. Platelet adhesiveness is critically dependent on agonist-induced inside-out activation of heterodimeric integrin receptors by a mechanism involving the recruitment of talin-1 to the cytoplasmic integrin tail. Experiments in heterologous cells have suggested a critical role of Rap1-guanosine triphosphate-interacting adaptor molecule (RIAM) for talin-1 recruitment and thus integrin activation, but direct in vivo evidence to support this has been missing. We generated RIAM-null mice and found that they are viable, fertile, and apparently healthy. Unexpectedly, platelets from these mice show unaltered beta3- and beta1-integrin activation and consequently normal adhesion and aggregation responses under static and flow conditions. Similarly, hemostasis and arterial thrombus formation were indistinguishable between wild-type and RIAM-null mice. These results reveal that RIAM is dispensable for integrin activation and function in mouse platelets, strongly suggesting the existence of alternative mechanisms of talin-1 recruitment. |