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PP2A

Wednesday 17 October 2007

Protein phosphatase 2A (PP2A) is a heterotrimeric serine/threonine phosphatase. It has been implicated in a variety of regulatory processes, including cell growth and division, muscle contraction, and gene transcription.

PP2A is composed of a 36-kD catalytic subunit (MIM.176915), a highly homologous 65-kD structural subunit (MIM.176915), and any of several different regulatory subunits that control its specificity.

Function

Protein phosphorylation is a regulatory mechanism commonly employed in cellular processes such as cell cycle progression, growth factor signaling, and cell transformation.

Reversible protein phosphorylation plays a central role in regulating intracellular signaling.

Dysregulation of the mechanisms that regulate phosphorylation plays a direct role in cancer initiation and maintenance.

Although abundant evidence supports the role of kinase oncogenes in cancer development, recent work has illuminated the role of specific protein phosphatases in malignant transformation.

Protein phosphatase 2A (PP2A) is the major serine-threonine phosphatase in mammalian cells.

Pathology

Inactivation of PP2A by viral oncoproteins, mutation of specific subunits or overexpression of endogenous inhibitors contributes to cell transformation by regulating specific phosphorylation events.

Subunits

PPP2CA PPP2R1A PPP2R2C PPP2R3B PPP2R4

References

- Westermarck J, Hahn WC. Multiple pathways regulated by the tumor suppressor PP2A in transformation. Trends Mol Med. 2008 Apr;14(4):152-60. PMID: 18329957

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