LIMK1

null LIMK1 is a kinase of the LISK family built from two N-terminal LIM domains, a PDZ domain and a catalytic kinase domain with mixed serine-threonine and tyrosine specificity. Activated by Rho-associated kinase (ROCK) and PAK downstream of the Rho and Rac GTPases, LIMK1 phosphorylates the actin-depolymerizing factor cofilin on a serine near its N-terminus, inactivating cofilin and stabilizing F-actin; this switch governs actin dynamics in growth cones, lamellipodia and stress fibers. LIMK1 lies within the Williams-Beuren syndrome deletion region and has been linked to cognitive phenotypes, while its overexpression in tumors promotes invasion and mitotic abnormalities. Recombinant LIMK1 supports cofilin phosphorylation assays and ROCK-pathway inhibitor screening.