p-MYLK (Ser 439) Antibody: sc-16800

MYLK Background Information
The Ca++/calmodulin-dependent protein kinase (CaM kinases) are a structurally related subfamily of serine/threonine kinases that includes CaMKI, CaMKII, CaMKIV and myosin light chain kinases (MLCKs). MLCK isoforms include non-muscle MLCK, smooth muscle MLCK and skeletal muscle MLCK (MLCKSK). Endothelial cell MLCK triggers actomyosin contractions essential for vascular barrier regulation and leukocyte diapedesis. Two high molecular weight MLCK splice variants in human endothelium, MLCK-1 and MLCK-2, are identical except for a deleted region in MLCK-2, which encodes a 69-amino acid stretch that contains potentially important consensus sites for phosphorylation by p60src kinase. The sites of tyrosine phosphorylation on MLCK-1 that are catalyzed by p60Src are Tyr 464 and Tyr 471, and they reside within the 69-residue stretch that is deleted in the MLCK-2 splice variant. Thus, p60Src-mediated tyrosine phosphorylation may provide an important mechanism for splice variant-specific regulation of non-muscle MLCK and vascular cell function.