Protein phosphatase 1A is an enzyme that in humans is encoded by the PPM1Agene.[1][2]
The protein encoded by this gene is a member of the PP2C family of Ser/Thr protein phosphatases. PP2C family members are known to be negative regulators of cell stress response pathways. This phosphatase dephosphorylates, and negatively regulates the activities of, MAP kinases and MAP kinase kinases. It has been shown to inhibit the activation of p38 and JNK kinase cascades induced by environmental stresses. This phosphatase can also dephosphorylate cyclin-dependent kinases, and thus may be involved in cell cycle control. Overexpression of this phosphatase is reported to activate the expression of the tumor suppressor gene TP53/p53, which leads to G2/M cell cycle arrest and apoptosis. Three alternatively spliced transcript variants encoding two distinct isoforms have been described.[2]
Interactions
PPM1A has been shown to interact with Metabotropic glutamate receptor 3.[3]
In 2006, Dr. Feng found that PPM1A can terminate TGF-beta signaling by inactivating Smad3 via dephosphorylation. Smad3 is an essential component of the TGF-beta signalling pathway.
Fjeld CC, Denu JM (1999). "Kinetic analysis of human serine/threonine protein phosphatase 2Calpha". J. Biol. Chem. 274 (29): 20336–43. doi:10.1074/jbc.274.29.20336. PMID10400656.
Hishiya A, Ohnishi M, Tamura S, Nakamura F (1999). "Protein phosphatase 2C inactivates F-actin binding of human platelet moesin". J. Biol. Chem. 274 (38): 26705–12. doi:10.1074/jbc.274.38.26705. PMID10480873.
Strovel ET, Wu D, Sussman DJ (2000). "Protein phosphatase 2Calpha dephosphorylates axin and activates LEF-1-dependent transcription". J. Biol. Chem. 275 (4): 2399–403. doi:10.1074/jbc.275.4.2399. PMID10644691.
Lifschitz-Mercer B, Sheinin Y, Ben-Meir D, et al. (2001). "Protein phosphatase 2Calpha expression in normal human tissues: an immunohistochemical study". Histochem. Cell Biol. 116 (1): 31–9. doi:10.1007/s004180100291. PMID11479720.
Srivastava J, Goris J, Dilworth SM, Parker PJ (2002). "Dephosphorylation of PKCdelta by protein phosphatase 2Ac and its inhibition by nucleotides". FEBS Lett. 516 (1–3): 265–9. doi:10.1016/S0014-5793(02)02500-0. PMID11959144.
Ofek P, Ben-Meir D, Kariv-Inbal Z, et al. (2003). "Cell cycle regulation and p53 activation by protein phosphatase 2C alpha". J. Biol. Chem. 278 (16): 14299–305. doi:10.1074/jbc.M211699200. PMID12514180.
Matsuda A, Suzuki Y, Honda G, et al. (2003). "Large-scale identification and characterization of human genes that activate NF-kappaB and MAPK signaling pathways". Oncogene. 22 (21): 3307–18. doi:10.1038/sj.onc.1206406. PMID12761501.
Ota T, Suzuki Y, Nishikawa T, et al. (2004). "Complete sequencing and characterization of 21,243 full-length human cDNAs". Nat. Genet. 36 (1): 40–5. doi:10.1038/ng1285. PMID14702039.
Yoshizaki T, Maegawa H, Egawa K, et al. (2004). "Protein phosphatase-2C alpha as a positive regulator of insulin sensitivity through direct activation of phosphatidylinositol 3-kinase in 3T3-L1 adipocytes". J. Biol. Chem. 279 (21): 22715–26. doi:10.1074/jbc.M313745200. PMID15016818.
Li D, Wang F, Lai M, et al. (2005). "A protein phosphatase 2calpha-Ca2+ channel complex for dephosphorylation of neuronal Ca2+ channels phosphorylated by protein kinase C.". J. Neurosci. 25 (8): 1914–23. doi:10.1523/JNEUROSCI.4790-04.2005. PMID15728831.