Myosin light-chain kinase

Patent Granted Myosin light-chain kinase also known as MYLK or MLCK is a serine/threonine-specific protein kinase that phosphorylates the regulatory light chain of myosin II. These enzymes are important in the mechanism of contraction in muscle. Once there is an influx of calcium cations (Ca2+) into the muscle, either from the sarcoplasmic reticulum or from the extracellular space, contraction of smooth muscle fibres may begin. First, the calcium will bind to calmodulin. This binding will activate MLCK, which will go on to phosphorylate the myosin light chain at serine residue 19.