Protein Kinase Classification:      CAMK/MLCK

※ MLCK family introduction

    MLCK (myosin light chain kinase) belongs to CAMK group and is Ca2+/calmodulin-dependent serine−threonine protein kinase which can phosphorylate the regulatory light chain of mysosin. Skeletal muscle MLCK contains an N-terminal sequence, a protein kinase catalytic core domain and a regulatory segment which consists of an autoinhibitory sequence and a calmodulin binding sequence. The expression size of MLCK in different animal species is related with diverse N-terminal sequence. The MLCKs are activated via binding with calmodulin which is a highly conserved Ca2+-binding protein (1). NMM (nonmuscle myosin) and SMM (smooth muscle myosin) are known substrates of MLCK in vivo. Phosphorylation of RLC on moysin can activate actin-activated myosin ATPase activity which is essential for muscle contraction. In addition, the phosphorylation functions of MLCKs in tracheal, bronchial and gastrointestinal smooth muscle cannot be replaced by others kinases (2).

Reference
1. Stull, J.T., Kamm, K.E. and Vandenboom, R. (2011) Myosin light chain kinase and the role of myosin light chain phosphorylation in skeletal muscle. Arch Biochem Biophys, 510, 120-128. PMID: 21284933
2. Hong, F., Haldeman, B.D., Jackson, D., Carter, M., Baker, J.E. and Cremo, C.R. (2011) Biochemistry of smooth muscle myosin light chain kinase. Arch Biochem Biophys, 510, 135-146. PMID: 21565153


CAMK MLCK in eukaryotes:

Ailuropoda melanoleuca (5)Anas platyrhynchos (6)Anolis carolinensis (4)
Astyanax mexicanus (12)Bos taurus (5)Caenorhabditis elegans (4)
Callithrix jacchus (5)Canis familiaris (5)Carlito syrichta (4)
Cavia porcellus (4)Cercocebus atys (5)Chlorocebus sabaeus (5)
Choloepus hoffmanni (3)Ciona intestinalis (5)Ciona savignyi (4)
Danio rerio (9)Dasypus novemcinctus (4)Dioscorea rotundata (1)
Dipodomys ordii (4)Drosophila melanogaster (4)Echinops telfairi (4)
Equus caballus (4)Erinaceus europaeus (3)Felis catus (4)
Ficedula albicollis (6)Fukomys damarensis (4)Gadus morhua (7)
Gallus gallus (5)Gasterosteus aculeatus (6)Gorilla gorilla (5)
Homo sapiens (5)Hordeum vulgare (1)Ictidomys tridecemlineatus (4)
Latimeria chalumnae (6)Lepisosteus oculatus (6)Loxodonta africana (5)
Macaca fascicularis (5)Macaca mulatta (4)Magnaporthe oryzae (1)
Meleagris gallopavo (5)Mesocricetus auratus (4)Microcebus murinus (3)
Monodelphis domestica (4)Mustela putorius furo (5)Mus musculus (5)
Myotis lucifugus (3)Nicotiana attenuata (1)Nomascus leucogenys (4)
Ochotona princeps (5)Octodon degus (4)Oreochromis niloticus (7)
Ornithorhynchus anatinus (4)Oryctolagus cuniculus (5)Oryza sativa (1)
Oryzias latipes (6)Ostreococcus lucimarinus (1)Otolemur garnettii (4)
Ovis aries (5)Pan paniscus (5)Pan troglodytes (5)
Papio anubis (5)Pelodiscus sinensis (5)Petromyzon marinus (7)
Poecilia formosa (7)Pongo abelii (5)Procavia capensis (5)
Pteropus vampyrus (5)Rattus norvegicus (4)Sarcophilus harrisii (3)
Sorex araneus (2)Sorghum bicolor (1)Sus scrofa (4)
Taeniopygia guttata (6)Takifugu rubripes (6)Tetraodon nigroviridis (6)
Trichoderma virens (1)Tupaia belangeri (3)Tursiops truncatus (5)
Vicugna pacos (4)Xenopus tropicalis (4)Xiphophorus maculatus (7)