PP2A
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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