| Structural highlights
Function
[PTPA2_YEAST] 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 TAP42-associated PP2A-like phosphatases modulating their activity or substrate specificity, probably by inducing a conformational change in the catalytic subunit, a direct target of the PPIase. Can reactivate inactive phosphatase PP2A-phosphatase methylesterase complexes (PP2Ai) in presence of ATP and Mg(2+) by dissociating the inactive form from the complex. Acts also inhibitory at high concentrations. Involved in the regulation of cell cycle progression, mitotic spindle formation and bud morphogenesis.[1] [2] [3] [4] [5] [6]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
PTPA, an essential and specific activator of protein phosphatase 2A (PP2A), functions as a peptidyl prolyl isomerase (PPIase). We present here the crystal structures of human PTPA and of the two yeast orthologs (Ypa1 and Ypa2), revealing an all alpha-helical protein fold that is radically different from other PPIases. The protein is organized into two domains separated by a groove lined by highly conserved residues. To understand the molecular mechanism of PTPA activity, Ypa1 was cocrystallized with a proline-containing PPIase peptide substrate. In the complex, the peptide binds at the interface of a peptide-induced dimer interface. Conserved residues of the interdomain groove contribute to the peptide binding site and dimer interface. Structure-guided mutational studies showed that in vivo PTPA activity is influenced by mutations on the surface of the peptide binding pocket, the same mutations that also influenced the in vitro activation of PP2Ai and PPIase activity.
Crystal structure of the PP2A phosphatase activator: implications for its PP2A-specific PPIase activity.,Leulliot N, Vicentini G, Jordens J, Quevillon-Cheruel S, Schiltz M, Barford D, van Tilbeurgh H, Goris J Mol Cell. 2006 Aug 4;23(3):413-24. PMID:16885030[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Van Hoof C, Janssens V, De Baere I, Stark MJ, de Winde JH, Winderickx J, Thevelein JM, Merlevede W, Goris J. The Saccharomyces cerevisiae phosphotyrosyl phosphatase activator proteins are required for a subset of the functions disrupted by protein phosphatase 2A mutations. Exp Cell Res. 2001 Apr 1;264(2):372-87. PMID:11262194 doi:http://dx.doi.org/10.1006/excr.2000.5144
- ↑ Mitchell DA, Sprague GF Jr. The phosphotyrosyl phosphatase activator, Ncs1p (Rrd1p), functions with Cla4p to regulate the G(2)/M transition in Saccharomyces cerevisiae. Mol Cell Biol. 2001 Jan;21(2):488-500. PMID:11134337 doi:http://dx.doi.org/10.1128/MCB.21.2.488-500.2001
- ↑ Fellner T, Lackner DH, Hombauer H, Piribauer P, Mudrak I, Zaragoza K, Juno C, Ogris E. A novel and essential mechanism determining specificity and activity of protein phosphatase 2A (PP2A) in vivo. Genes Dev. 2003 Sep 1;17(17):2138-50. PMID:12952889 doi:http://dx.doi.org/10.1101/gad.259903
- ↑ Van Hoof C, Martens E, Longin S, Jordens J, Stevens I, Janssens V, Goris J. Specific interactions of PP2A and PP2A-like phosphatases with the yeast PTPA homologues, Ypa1 and Ypa2. Biochem J. 2005 Feb 15;386(Pt 1):93-102. PMID:15447631 doi:http://dx.doi.org/10.1042/BJ20040887
- ↑ Zheng Y, Jiang Y. The yeast phosphotyrosyl phosphatase activator is part of the Tap42-phosphatase complexes. Mol Biol Cell. 2005 Apr;16(4):2119-27. Epub 2005 Feb 2. PMID:15689491 doi:http://dx.doi.org/E04-09-0797
- ↑ Jordens J, Janssens V, Longin S, Stevens I, Martens E, Bultynck G, Engelborghs Y, Lescrinier E, Waelkens E, Goris J, Van Hoof C. The protein phosphatase 2A phosphatase activator is a novel peptidyl-prolyl cis/trans-isomerase. J Biol Chem. 2006 Mar 10;281(10):6349-57. Epub 2005 Dec 27. PMID:16380387 doi:http://dx.doi.org/M507760200
- ↑ Leulliot N, Vicentini G, Jordens J, Quevillon-Cheruel S, Schiltz M, Barford D, van Tilbeurgh H, Goris J. Crystal structure of the PP2A phosphatase activator: implications for its PP2A-specific PPIase activity. Mol Cell. 2006 Aug 4;23(3):413-24. PMID:16885030 doi:10.1016/j.molcel.2006.07.008
|
