Protein phosphatase 1 regulatory subunit 12B is an enzyme that in humans is encoded by the PPP1R12Bgene.[5][6]
Myosin light chain phosphatase (MLCP) consists of three subunits- catalytic subunit, large subunit/myosin binding subunit (MBS) and small subunit (sm-M20). This gene is a multi-functional gene which encodes both MBS and sm-M20. MLCP regulates myosins and the dephosphorylation is enhanced by the presence of MBS. The sm-M20 is suggested to play a regulatory role in muscle contraction by binding to MBS. MBS is also encoded by another gene, myosin light chain phosphatase target subunit 1. sm-M20 shows higher binding affinity to this gene product than to myosin light chain phosphatase target subunit 2-MBS even though the two MBS proteins are highly similar. Although both MBSs increase the activity of MLCP, myosin light chain phosphatase target subunit 1-MBS is a more efficient activator. There are four alternatively spliced transcript variants described; two alter the MBS coding region and two alter the sm-M20 coding region of this gene.[6]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Fujioka M, Takahashi N, Odai H, Araki S, Ichikawa K, Feng J, Nakamura M, Kaibuchi K, Hartshorne DJ, Nakano T, Ito M (Jun 1998). "A new isoform of human myosin phosphatase targeting/regulatory subunit (MYPT2): cDNA cloning, tissue expression, and chromosomal mapping". Genomics. 49 (1): 59–68. doi:10.1006/geno.1998.5222. PMID9570949.
Moorhead G, Johnson D, Morrice N, Cohen P (1998). "The major myosin phosphatase in skeletal muscle is a complex between the beta-isoform of protein phosphatase 1 and the MYPT2 gene product". FEBS Lett. 438 (3): 141–4. doi:10.1016/S0014-5793(98)01276-9. PMID9827534. S2CID35052936.
Okamoto R, Kato T, Mizoguchi A, et al. (2007). "Characterization and function of MYPT2, a target subunit of myosin phosphatase in heart". Cell. Signal. 18 (9): 1408–16. doi:10.1016/j.cellsig.2005.11.001. PMID16431080.