Paxillin.

Paxillin is a 68 kDa cytoplasmic protein that localizes to discrete sites of cell attachment to the extracellular matrix called focal adhesions. It is a multi-domain adapter protein capable of interacting with several structural and signaling proteins including vinculin, FAK, PYK2, Src and Crk. Phosphorylation of paxillin in response to integrin-mediated cell adhesion and growth factor stimulation regulates some of these interactions. Thus, paxillin functions as a scaffold for the recruitment of molecules into a signal transduction complex that is closely apposed to the plasma membrane. This is likely to facilitate the efficient processing of external stimuli that modulate important cellular events including cell adhesion, cell motility and growth control. Since paxillin interacts with several proteins known to cause cell transformation, the binding sites for these proteins on paxillin represent potential targets for therapeutic agents.