Integrins and mechanotransduction of the vascular myogenic response

This review summarizes what is currently known about the role of integrins in the vascular myogenic response. The myogenic response is the rapid and m aintained constriction of a blood vessel in response to pressure elevation. A role for integrins in this process has been suggested because these mole cules form an important mechanical link between the extracellular matrix an d the vascular smooth muscle cytoskeleton. We briefly summarize evidence fo r a general role of integrins in mechanotransduction. We then describe the integrin subunit combinations known to exist in smooth muscle and the vascu lar wall matrix proteins that may interact with these integrins. We then di scuss the effects of integrin- specific peptides and antibodies on vascular tone and on calcium entry mechanisms in vascular smooth muscle. Because in tegrin function is linked to the cytoskeleton, we discuss evidence for the role of the cytoskeleton in determining myogenic responsiveness. Finally, w e analyze evidence that integrin- linked signaling pathways, such as those involving protein tyrosine phosphorylation cascades and mitogen- activated protein kinases, are required for myogenic tone.