4lac

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Template:STRUCTURE 4lac

Contents

Crystal Structure of Protein Phosphatase 2A (PP2A) and PP2A phosphatase activator (PTPA) complex with ATPgammaS

Function

[PTPA_HUMAN] PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. Acts as a regulatory subunit for serine/threonine-protein phosphatase 2A (PP2A) modulating its activity or substrate specificity, probably by inducing a conformational change in the catalytic subunit, a proposed direct target of the PPIase. Can reactivate inactive phosphatase PP2A-phosphatase methylesterase complexes (PP2A(i)) in presence of ATP and Mg(2+) (By similarity). Reversibly stimulates the variable phosphotyrosyl phosphatase activity of PP2A core heterodimer PP2A(D) in presence of ATP and Mg(2+) (in vitro). The phosphotyrosyl phosphatase activity is dependent of an ATPase activity of the PP2A(D):PPP2R4 complex. Is involved in apoptosis; the function appears to be independent from PP2A.[1] [2] [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'.[3] [4] [5]

About this Structure

4lac is a 3 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

  1. Azam S, Drobetsky E, Ramotar D. Overexpression of the cis/trans isomerase PTPA triggers caspase 3-dependent apoptosis. Apoptosis. 2007 Jul;12(7):1243-55. PMID:17333320 doi:http://dx.doi.org/10.1007/s10495-006-0050-8
  2. Chao Y, Xing Y, Chen Y, Xu Y, Lin Z, Li Z, Jeffrey PD, Stock JB, Shi Y. Structure and mechanism of the phosphotyrosyl phosphatase activator. Mol Cell. 2006 Aug;23(4):535-46. PMID:16916641 doi:http://dx.doi.org/10.1016/j.molcel.2006.07.027
  3. Hsu W, Zeng L, Costantini F. Identification of a domain of Axin that binds to the serine/threonine protein phosphatase 2A and a self-binding domain. J Biol Chem. 1999 Feb 5;274(6):3439-45. PMID:9920888
  4. Abraham D, Podar K, Pacher M, Kubicek M, Welzel N, Hemmings BA, Dilworth SM, Mischak H, Kolch W, Baccarini M. Raf-1-associated protein phosphatase 2A as a positive regulator of kinase activation. J Biol Chem. 2000 Jul 21;275(29):22300-4. PMID:10801873 doi:10.1074/jbc.M003259200
  5. Watkins GR, Wang N, Mazalouskas MD, Gomez RJ, Guthrie CR, Kraemer BC, Schweiger S, Spiller BW, Wadzinski BE. Monoubiquitination promotes calpain cleavage of the protein phosphatase 2A (PP2A) regulatory subunit alpha4, altering PP2A stability and microtubule-associated protein phosphorylation. J Biol Chem. 2012 Jul 13;287(29):24207-15. doi: 10.1074/jbc.M112.368613. Epub, 2012 May 21. PMID:22613722 doi:10.1074/jbc.M112.368613

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