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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed October 2010

What is the official name of the PPP1R12A gene?

The official name of this gene is “protein phosphatase 1, regulatory subunit 12A.”

PPP1R12A is the gene's official symbol. The PPP1R12A gene is also known by other names, listed below.

What is the normal function of the PPP1R12A gene?

The PPP1R12A gene provides instructions for making a protein called myosin phosphatase target subunit 1. This protein functions as part of a larger enzyme called myosin phosphatase, which regulates the interaction of two important muscle proteins, actin and myosin. In muscle cells, actin and myosin work together to generate the force needed for the normal tensing (contraction) of muscles. Myosin phosphatase attaches to myosin and removes clusters of oxygen and phosphorus atoms (phosphate groups) as part of a complex pathway that allows muscles to contract and relax properly. Myosin phosphatase may also play a role in nonmuscle cells, particularly during cell division.

Myosin phosphatase target subunit 1 is responsible for recognizing the myosin protein and allowing myosin phosphatase to bind to it. The subunit is turned on and off in response to signals within the cell. For example, researchers have found that myosin phosphatase target subunit 1 interacts with the protein produced from the DMPK gene. The DMPK protein turns off (inhibits) the subunit by adding phosphate groups to it. When myosin phosphatase target subunit 1 is turned off, it cannot bind to myosin and the muscle does not contract.

Does the PPP1R12A gene share characteristics with other genes?

The PPP1R12A gene belongs to a family of genes called ANKRD (ankyrin repeat domain containing). It also belongs to a family of genes called serine/threonine phosphatases (serine/threonine phosphatases).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

Where is the PPP1R12A gene located?

Cytogenetic Location: 12q15-q21

Molecular Location on chromosome 12: base pairs 79,773,562 to 79,935,454

The PPP1R12A gene is located on the long (q) arm of chromosome 12 between positions 15 and 21.

The PPP1R12A gene is located on the long (q) arm of chromosome 12 between positions 15 and 21.

More precisely, the PPP1R12A gene is located from base pair 79,773,562 to base pair 79,935,454 on chromosome 12.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about PPP1R12A?

You and your healthcare professional may find the following resources about PPP1R12A helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the PPP1R12A gene or gene products?

  • M130
  • MBS
  • myosin-binding subunit of myosin phosphatase
  • Myosin phosphatase target subunit 1
  • MYPT1
  • protein phosphatase 1, regulatory (inhibitor) subunit 12A

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding PPP1R12A?

actin ; cell ; cell division ; contraction ; enzyme ; gene ; hypoxia ; muscle cells ; myosin ; oxygen ; phosphatase ; phosphate ; phosphorus ; protein ; subunit

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (


  • Murányi A, Zhang R, Liu F, Hirano K, Ito M, Epstein HF, Hartshorne DJ. Myotonic dystrophy protein kinase phosphorylates the myosin phosphatase targeting subunit and inhibits myosin phosphatase activity. FEBS Lett. 2001 Mar 30;493(2-3):80-4. (
  • NCBI Gene (
  • Pfitzer G. Invited review: regulation of myosin phosphorylation in smooth muscle. J Appl Physiol (1985). 2001 Jul;91(1):497-503. Review. (
  • Totsukawa G, Yamakita Y, Yamashiro S, Hosoya H, Hartshorne DJ, Matsumura F. Activation of myosin phosphatase targeting subunit by mitosis-specific phosphorylation. J Cell Biol. 1999 Feb 22;144(4):735-44. (
  • Webb JD, Murányi A, Pugh CW, Ratcliffe PJ, Coleman ML. MYPT1, the targeting subunit of smooth-muscle myosin phosphatase, is a substrate for the asparaginyl hydroxylase factor inhibiting hypoxia-inducible factor (FIH). Biochem J. 2009 May 13;420(2):327-33. doi: 10.1042/BJ20081905. (
  • Xia D, Stull JT, Kamm KE. Myosin phosphatase targeting subunit 1 affects cell migration by regulating myosin phosphorylation and actin assembly. Exp Cell Res. 2005 Apr 1;304(2):506-17. Epub 2004 Dec 30. (
  • Yamashiro S, Yamakita Y, Totsukawa G, Goto H, Kaibuchi K, Ito M, Hartshorne DJ, Matsumura F. Myosin phosphatase-targeting subunit 1 regulates mitosis by antagonizing polo-like kinase 1. Dev Cell. 2008 May;14(5):787-97. doi: 10.1016/j.devcel.2008.02.013. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: October 2010
Published: January 27, 2015