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Publication Abstract from PubMed

Protein phosphatase 2A (PP2A) holoenzymes target broad substrates by recognizing short motifs via regulatory subunits. PP2A methylesterase 1 (PME-1) is a cancer-promoting enzyme and undergoes methylesterase activation upon binding to the PP2A core enzyme. Here, we showed that PME-1 readily demethylates different families of PP2A holoenzymes and blocks substrate recognition in vitro. The high-resolution cryoelectron microscopy structure of a PP2A-B56 holoenzyme-PME-1 complex reveals that PME-1 disordered regions, including a substrate-mimicking motif, tether to the B56 regulatory subunit at remote sites. They occupy the holoenzyme substrate-binding groove and allow large structural shifts in both holoenzyme and PME-1 to enable multipartite contacts at structured cores to activate the methylesterase. B56 interface mutations selectively block PME-1 activity toward PP2A-B56 holoenzymes and affect the methylation of a fraction of total cellular PP2A. The B56 interface mutations allow us to uncover B56-specific PME-1 functions in p53 signaling. Our studies reveal multiple mechanisms of PME-1 in suppressing holoenzyme functions and versatile PME-1 activities derived from coupling substrate-mimicking motifs to dynamic structured cores.

Coupling to short linear motifs creates versatile PME-1 activities in PP2A holoenzyme demethylation and inhibition.,Li Y, Balakrishnan VK, Rowse M, Wu CG, Bravos AP, Yadav VK, Ivarsson Y, Strack S, Novikova IV, Xing Y Elife. 2022 Aug 4;11:e79736. doi: 10.7554/eLife.79736. PMID:35924897^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.