The UMD-MYLK mutations database
The protein

The MYLK protein (NP_444253.3; Q15746) is composed of 1914 amino acids, which gives a 211 kDa protein.

The MYLK gene encodes both muscle and nonmuscle isoforms of the myosin light chain kinase protein, which is a calcium/calmodulin dependent enzyme. It implicates in smooth muscle contraction via the phosphorylation of myosin light chains (MLC) and PTK2B/PYK2 proteins and regulates the interaction between actin and myosin through a non kinase activity. This protein is involved in several pathways such as inflammatory response (apoptosis, vascular permeability, leukocyte diapedesis), cell motility and morphology, airway hyperreactivity and other activities relative to asthma.

Isoform 1 is activated by phosphorylation on Tyr-464 and Tyr-471. Others isoforms which lack these tyrosine residues are not regulated in this way. All catalytically active isoforms require binding to calcium and calmodulin for activation. This protein is repressed by organometallic pyridylnaphthalimide complexes, wortmannin, ML-7 (a synthetic naphthalenesulphonyl derivative that inhibits the binding of ATP to MLCK) and ML-9.

In addition, using a separate promoter in an intron in the 3' region, it encodes telokin, a small protein identical in sequence to the C-terminus of myosin light chain kinase, that is independently expressed in smooth muscle and functions to stabilize unphosphorylated myosin filaments.

Table of domains coordinates  (Show/Hide)

Schematic representation of the MYLK protein  (Show/Hide)