3p71
From Proteopedia
Crystal structure of the complex of LCMT-1 and PP2A
Structural highlights
Function[LCMT1_HUMAN] Methylates the carboxyl group of the C-terminal leucine residue of protein phosphatase 2A catalytic subunits to form alpha-leucine ester residues.[1] [PP2AA_HUMAN] PP2A is the major phosphatase for microtubule-associated proteins (MAPs). PP2A can modulate the activity of phosphorylase B kinase casein kinase 2, mitogen-stimulated S6 kinase, and MAP-2 kinase. Cooperates with SGOL2 to protect centromeric cohesin from separase-mediated cleavage in oocytes specifically during meiosis I (By similarity). Can dephosphorylate SV40 large T antigen and p53/TP53. Activates RAF1 by dephosphorylating it at 'Ser-259'.[2] [3] [4] Publication Abstract from PubMedProper formation of protein phosphatase 2A (PP2A) holoenzymes is essential for the fitness of all eukaryotic cells. Carboxyl methylation of the PP2A catalytic subunit plays a critical role in regulating holoenzyme assembly; methylation is catalyzed by PP2A-specific methyltransferase LCMT-1, an enzyme required for cell survival. We determined crystal structures of human LCMT-1 in isolation and in complex with PP2A stabilized by a cofactor mimic. The structures show that the LCMT-1 active-site pocket recognizes the carboxyl terminus of PP2A, and, interestingly, the PP2A active site makes extensive contacts to LCMT-1. We demonstrated that activation of the PP2A active site stimulates methylation, suggesting a mechanism for efficient conversion of activated PP2A into substrate-specific holoenzymes, thus minimizing unregulated phosphatase activity or formation of inactive holoenzymes. A dominant-negative LCMT-1 mutant attenuates the cell cycle without causing cell death, likely by inhibiting uncontrolled phosphatase activity. Our studies suggested mechanisms of LCMT-1 in tight control of PP2A function, important for the cell cycle and cell survival. The Structural Basis for Tight Control of PP2A Methylation and Function by LCMT-1.,Stanevich V, Jiang L, Satyshur KA, Li Y, Jeffrey PD, Li Z, Menden P, Semmelhack MF, Xing Y Mol Cell. 2011 Feb 4;41(3):331-42. PMID:21292165[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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