Paxillin is a focal adhesion-associated adaptor protein and a substrate for a number of tyrosine kinases such as src, FAK, and p210BRC/ABL. The tyrosine phosphorylation of paxillin is influenced by conditions that change cell-cell adhesion. Paxillin is linked strongly with FAK and Crk through its SH2 domain which is independent of the extracellular matrix. While paxillin was initially revealed in fibroblasts, its phosphorylation is significant throughout neurite extension during differentiation. paxillin is a regulator of sex differences in neuronal morphology. Paxillin is involved in signaling pathways and contains several motifs that mediate protein-protein interactions, as well as LD motifs, LIM domains, an SH3 domain-binding site and SH2 domain-binding sites. These motifs act as docking sites for cytoskeletal proteins, tyrosine kinases, serine/threonine kinases, GTPase activating proteins and several adaptor proteins that recruit other enzymes into complex with paxillin. paxillin regulates cell spreading and motility Synonyms: PXN, Paxillin, FLJ16691