1gfy
RESIDUE 259 IS A KEY DETERMINANT OF SUBSTRATE SPECIFICITY OF PROTEIN-TYROSINE PHOSPHATASE 1B AND ALPHA
Structural highlights
FunctionPTN1_HUMAN Tyrosine-protein phosphatase which acts as a regulator of endoplasmic reticulum unfolded protein response. Mediates dephosphorylation of EIF2AK3/PERK; inactivating the protein kinase activity of EIF2AK3/PERK. May play an important role in CKII- and p60c-src-induced signal transduction cascades. May regulate the EFNA5-EPHA3 signaling pathway which modulates cell reorganization and cell-cell repulsion.[1] [2] 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 PubMedThe aim of this study was to define the structural elements that determine the differences in substrate recognition capacity of two protein-tyrosine phosphatases (PTPs), PTP1B and PTPalpha, both suggested to be negative regulators of insulin signaling. Since the Ac-DADE(pY)L-NH(2) peptide is well recognized by PTP1B, but less efficiently by PTPalpha, it was chosen as a tool for these analyses. Calpha regiovariation analyses and primary sequence alignments indicate that residues 47, 48, 258, and 259 (PTP1B numbering) define a selectivity-determining region. By analyzing a set of DADE(pY)L analogs with a series of PTP mutants in which these four residues were exchanged between PTP1B and PTPalpha, either in combination or alone, we here demonstrate that the key selectivity-determining residue is 259. In PTPalpha, this residue is a glutamine causing steric hindrance and in PTP1B a glycine allowing broad substrate recognition. Significantly, replacing Gln(259) with a glycine almost turns PTPalpha into a PTP1B-like enzyme. By using a novel set of PTP inhibitors and x-ray crystallography, we further provide evidence that Gln(259) in PTPalpha plays a dual role leading to restricted substrate recognition (directly via steric hindrance) and reduced catalytic activity (indirectly via Gln(262)). Both effects may indicate that PTPalpha regulates highly selective signal transduction processes. Residue 259 is a key determinant of substrate specificity of protein-tyrosine phosphatases 1B and alpha.,Peters GH, Iversen LF, Branner S, Andersen HS, Mortensen SB, Olsen OH, Moller KB, Moller NP J Biol Chem. 2000 Jun 16;275(24):18201-9. PMID:10748206[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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