Function and Regulation of the β3 Integrins in Hemostasis and Vascular Biology

The beta 3 integrins, alpha IIb beta 3 and alpha V beta 3, are prominently expressed on the surfaces of platelets and endothelial cells, respectively. This vascular localization places them in a strategic position to perform adhesive functions necessary for hemostasis, wound healing and angiogenesis. In addition, these integrins are now known to serve a signaling function, whereby environmental cues on either side of the plasma membrane can be transmitted across the membrane to the other side. Indeed, preliminary studies indicate that these dual function receptors are wired to other signaling pathways within platelets and endothelial cells, thus helping to explain how integrin-mediated cell anchorage can affect cytoskeletal organization and cell motility as well as endothelial cell growth, differentiation and apoptosis.