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. Author manuscript; available in PMC: 2014 Jul 10.
Published in final edited form as: Cancer Lett. 2013 Feb 20;335(1):9–18. doi: 10.1016/j.canlet.2013.02.036

Figure 3. Representation of PP2A regulation and signaling pathways.

Figure 3

Methylation and phosphorylation are two major post translation modifications of PP2A. The conserved sequence TPDYFL in PP2Ac undergoes phosphorylation and methylation, respectively. Phosphorylation of Y307 by receptor associated tyrosine kinases effectively decreases the PP2A activity by inhibiting the interaction of the catalytic subunit with the scaffold subunit. On the other hand, the addition of the methyl group to PP2Ac by LCMT1 at L309 by PP2A-methyltransferase (PPMT) will enhance the specific binding of the AC dimer to the distinct B regulatory subunit providing the enzymatic activity. PP2A activity is indispensable for every cell and takes part in the majority of the cellular pathways. Phosphorylation at Thr-308 and Ser-473 leads to activation of Akt and is associated with PP2A activation. PP2A also possesses a vital role in the Wnt signaling pathway and phosphorylation of PP2A-B56 directs the activation of the Wnt pathway. In addition to these pathways, PP2A activity is indispensable in apoptosis. BAD (pro-apoptotic) and Bcl-2 are also regulated by PP2A. Phosphorylation of BAD suppresses, and its dephosphorylation by PP2A promotes pro-apoptotic activity. In addition, phosphorylation of Bcl-2 activates, and its dephosphorylation by PP2A suppresses anti-apoptotic activity. Thus, this diagrammatic representation will elucidate the importance of PP2A during cell growth survival and apoptosis.