LIMK1, a member of the Ser/Thr protein kinase family, may be a component of an intracellular signaling pathway and may be involved in brain development. It phosphorylates and inactivates the actin binding/depolymerizing factor cofilin and induces actin cytoskeletal changes. The LIM domain interacts with the cytoplasmic domain of NRG1, and this cytoplasmic protein also binds ROCK1, whic phosphorylates LIMK1 on serine and/or threonine residues. Highest expression occurs in both adult and fetal nervous systems. It is detected ubiquitously throughout the different regions of adult brain, with highest levels in the cerebral cortex, and is expressed to a lesser extent in heart and skeletal muscle. Haploinsufficiency of LIMK1 may be the cause of certain cardiovascular and musculo-skeletal abnormalities observed in Williams-Beuren syndrome (WBS), a rare developmental disorder. It is a contiguous gene deletion syndrome involving genes from chromosome band 7q11.23. This protein contains 2 LIM zinc-binding domains and 1 PDZ/DHR domain.