|Protein Name||Myosin regulatory light chain 12B|
|Milk Fraction||MFGM, Exosome|
|Ref Sequence ID||NP_001077233.1|
|Protein Existence Status||Reviewed: Experimental evidence at transcript level|
|Presence in other biological fluids/tissue/cells||Myosin light chain (Myl), Myl12a and Myl12b were expressed abundantly in most tissues except the brain (Myl12a) and striated muscles (Myl12b) (Figure 2A and 2B). Notably, the expression of Myl9 was highest in smooth muscle such as that of the bladder|
|Protein Function||regulate MHC II activity principally by phosphorylation of which increases the Mg2+-ATPase activity of myosin by regulating the conformation of myosin heads; RLCs stabilize MHCs|
|Biochemical Properties||divalent cations and at 37 °C favor weak binding of the light chain; antibodies against LC2 light chain could dissociate up to50% of the light chain at 4 °C; raising the temperature favors dissociation of a myosin totally devoid of LC2 light chain; Electron micrographs of rotary shadowed LC2-deficient myosin show the formation of oligomeric structures, which are primarily dimers and trimers; exposed LC2 binding site leads to "sticky patches" causing intermolecular aggregation between two or more myosin molecules at the "neck" region of the head near the rod junction; absence of LC2 light chain does not affect the myosin enzymatic activity|
|Significance in milk||Cytoskeletal proteins; found increased during infection|
|PTMs||As found in cow's mammary gland, this protein is phosphorylated by PKC, cofactor 1-Oleoyl-2-acetyl-sn-glycerol, phosphotidyl serine and Ca2+; Phosphorylation of myosin light chains from heart is studied in humans and rats; tyrosine nitration has been implicated in many pathological conditions and diseases such as inflammation, chronic hypoxia, myocardial infarction and diabetes; in chicken gizzard phosphorylation of this protein is done by PS and Ca2+|
| Site(s) of PTM(s) |
|Predicted Disorder Regions||NA|
|TM Helix Prediction||No TM helices|
|Significance of PTMs||in cow's mammary gland, phosphorylation of this protein induces actin-myosin interaction therby initiating cell contraction; Phosphorylation in heart of myosin light chain 1 has been associated with stability of the myosin head - phosphorylation of MLC1 has direct implications in its degradation by MMP-2; Nitration of protein tyrosine residues has been suggested to facilitate proteolysis of the nitrated protein; subjected to tyrosine nitration and cysteine s-nitrosylation in cardiac models of oxidative stress|
|Bibliography||1. Pastra-Landis, S. C. and Lowey, S. (1986) ‘Myosin subunit interactions. Properties of the 19,000-dalton light chain-deficient myosin.’, The Journal of biological chemistry, 261(31), pp. 14811–6. Available at: http://www.ncbi.nlm.nih.gov/pubmed/3771553 (Accessed: 4 October 2019). |
2. Park, I. et al. (2011) ‘Myosin regulatory light chains are required to maintain the stability of myosin II and cellular integrity’, Biochemical Journal, 434(1), pp. 171–180. doi: 10.1042/BJ20101473.
3. KATOH, N. (2005) ‘Similarities of Cow Mammary Gland Cytosolic 21-kDa Protein, the Substrate for Protein Kinase C, to the 20-kDa Myosin Light Chain from Smooth Muscle’, Journal of Veterinary Medical Science, 67(1), pp. 29–34. doi: 10.1292/jvms.67.29.
4. Doroszko, A. et al. (2010) ‘Neonatal Asphyxia Induces the Nitration of Cardiac Myosin Light Chain 2 That is Associated with Cardiac Systolic Dysfunction’, Shock, 34(6), pp. 592–600. doi: 10.1097/SHK.0b013e3181e14f1d.
5. Doroszko, A. et al. (2009) ‘Cardiac dysfunction in an animal model of neonatal asphyxia is associated with increased degradation of MLC1 by MMP-2’, Basic Research in Cardiology, 104(6), pp. 669–679. doi: 10.1007/s00395-009-0035-1.
6. Yakovlev, V. A. and Mikkelsen, R. B. (2010) ‘Protein tyrosine nitration in cellular signal transduction pathways’, Journal of Receptors and Signal Transduction, 30(6), pp. 420–429. doi: 10.3109/10799893.2010.513991.