Phosphorylation of LIMK-1 by PAK

LIM kinases are serine protein kinases with a unique combination of two N-terminal LIM motifs, a central PDZ domain, and a C-terminal protein kinase domain. LIMK1 is one of the downstream targets of PAK1 and is activated through phosphorylation by PAK1 on T508 within its activation loop (Edwards et al. 1999, Aizawa et al. 2001). LIM-kinase is responsible for the tight regulation of the activity of cofilin (a protein that depolymerizes actin filaments) and thus maintains the balance between actin assembly and disassembly. Phosphorylated cofilin is inactive, resulting in stabilization of the actin cytoskeleton.

LIM激酶为一种独特的丝氨酸蛋白激酶，其特征在于N端具有两个LIM基序的组合、中央的PDZ结构域以及C端的蛋白激酶结构域。LIMK1是PAK1下游目标之一，通过PAK1在其激活环上的T508位点的磷酸化而被激活（Edwards等人，1999年，Aizawa等人，2001年）。LIM激酶负责严格调控肌动蛋白去聚化蛋白（一种使肌动蛋白丝解聚的蛋白）的活性，从而维持肌动蛋白组装与解聚之间的平衡。磷酸化的肌动蛋白去聚化蛋白处于非活性状态，导致肌动蛋白细胞骨架的稳定化。