Catalytic domain of an unknown subfamily of LIM domain kinase-like protein kinases
PKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine or tyrosine residues on protein substrates. This group is composed of uncharacterized proteins with similarity to LIMK and Testicular or testis-specific protein kinase (TESK). LIMKs are characterized as serine/threonine kinases (STKs) while TESKs are dual-specificity protein kinases. Both LIMK and TESK phosphorylate and inactivate cofilin, an actin depolymerizing factor, to induce the reorganization of the actin cytoskeleton. They are implicated in many cellular functions including cell spreading, motility, morphogenesis, meiosis, mitosis, and spermatogenesis. The LIMK-like subfamily is part of a larger superfamily that includes the catalytic domains of other STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.