The Full Wiki

More info on PP2A

PP2A: Wikis


Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.


(Redirected to Protein phosphatase 2 article)

From Wikipedia, the free encyclopedia

protein phosphatase 2 (formerly 2A), catalytic subunit, alpha isoform
Symbol PPP2CA
Entrez 5515
HUGO 9299
OMIM 176915
RefSeq NM_002715
UniProt P67775
Other data
EC number
Locus Chr. 5 q23-q31

Protein phosphatase 2 (PP2) also known as PP2A is an enzyme that in humans is encoded by the PPP2CA gene.[1] The PP2A heterotrimeric protein phosphatase, is a ubiquitous and conserved Serine/Threonine phosphatase with broad substrate specificity and diverse cellular functions. Among the targets of PP2A are proteins of oncogenic signaling cascades, such as Raf, MEK, and AKT.


Structure and function

PP2A consists of a dimeric core enzyme comprising of the structural A and catalytic C subunits, and a regulatory B subunit. When the PP2A catalytic C subunit associates with the A and B subunits several species of holoenzymes are produced with distinct functions and characteristics. The A subunit, a founding member of the HEAT repeat protein family (huntington-elongation-A subunit-TOR), is the scaffold required for the formation of the heterotrimeric complex. When the A subunit binds it alters the enzymatic activity of the catalytic subunit, even if the B subunit is absent. While C and A subunit sequences show remarkable sequence conservation throughout eukaryotes, regulatory B subunits are more heterogeneous and are believed to play key roles in controlling the localization and specific activity of different holoenzymes. Multicellular eukaryotes express four classes of variable regulatory subunits: B (PR55), Bˈ (B56 or PR61), Bˈˈ (PR72), and Bˈˈˈ (PR93/PR110), with at least 16 members in these subfamilies. In Addition, accessory proteins and posttranslational modifications (such as methylation) control PP2A subunit associations and activities.

The two catalytic metal ions located at bottom of PP2A's active site have been recently identified as manganese, which had previously been suggested as potential candidates.


  1. ^ Jones TA, Barker HM, da Cruz e Silva EF, Mayer-Jaekel RE, Hemmings BA, Spurr NK, Sheer D, Cohen PT (1993). "Localization of the genes encoding the catalytic subunits of protein phosphatase 2A to human chromosome bands 5q23→q31 and 8p12→p11.2, respectively". Cytogenet. Cell Genet. 63 (1): 35–41. PMID 8383590.  

Further reading

  • Xu Y, Xing Y, Chen Y, Chao Y, Lin Z, Fan E, Yu JW, Strack S, Jeffrey PD, Shi Y (December 2006). "Structure of the protein phosphatase 2A holoenzyme". Cell 127 (6): 1239–51. doi:10.1016/j.cell.2006.11.033. PMID 17174897.  
  • Xing Y, Xu Y, Chen Y, Jeffrey PD, Chao Y, Lin Z, Li Z, Strack S, Stock JB, Shi Y (October 2006). "Structure of protein phosphatase 2A core enzyme bound to tumor-inducing toxins". Cell 127 (2): 341–53. doi:10.1016/j.cell.2006.09.025. PMID 17055435.  
  • Ory S, Zhou M, Conrads TP, Veenstra TD, Morrison DK (August 2003). "Protein phosphatase 2A positively regulates Ras signaling by dephosphorylating KSR1 and Raf-1 on critical 14-3-3 binding sites". Curr. Biol. 13 (16): 1356–64. PMID 12932319.  

External links



Got something to say? Make a comment.
Your name
Your email address