The p21Rac/Cdc42-activated kinases (PAKs).

The p21-activated kinases (PAKs) are mammalian Rac/Cdc42-associated serine/threonine protein kinases. They contain diverse structural regulatory elements that allow them not only to participate as effectors in signaling processes initiated by activated GTPases but also in signal transduction events mediated by Src3 homology domains (SH3) or caspase-mediated proteolytic cleavage. The biological functions of PAK protein kinases result from the interplay of N- and C-terminal-mediated protein-protein interactions and signals derived from phosphorylation of downstream substrates. The potential regulation of microbial killing, stress responses, apoptosis, and cell motility by PAKs suggest it may be a therapeutically useful target in a number of disease states.