Myosin light chain kinase 2 also known as MYLK2 is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
which in humans is encoded by the ''MYLK2''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Function
This gene encodes a
myosin light chain kinase, a
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar ...
/
calmodulin
Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the bin ...
dependent enzyme, that is exclusively expressed in adult skeletal muscle.
The MYLK2 gene expresses skMLCK more prevalently in fast twitch muscle fibers as compared to slow twitch muscle fibers. Calmodulin is composed of two terminal domains (N,C) each containing two E-F hand motifs that bind to Ca2+. Upon saturation of Ca2+, Calmodulin undergoes a conformation change allowing it to bind with a target protein such as skMLCK. An image depicting a similar complex (sdCen/skMLCK2) is shown under
myosin light chain kinase. This binding to skMLCK increases the affinity of Ca2+ and ultimately leads to a sustained muscle action.
Clinical significance
Mutations in the ''MYLK2'' gene have been linked to midventricular
hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy (HCM, or HOCM when obstructive) is a condition in which the heart becomes thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This r ...
.
References
Further reading
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EC 2.7.11
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