Crystal structure of the PTPRJ inactivating mutant C1239S
[PTPRJ_HUMAN] Tyrosine phosphatase which dephosphorylates or contributes to the dephosphorylation of CTNND1, FLT3, PDGFRB, MET, RET (variant MEN2A), KDR, LYN, SRC, MAPK1, MAPK3, EGFR, TJP1, OCLN, PIK3R1 and PIK3R2. Plays a role in cell adhesion, migration, proliferation and differentiation. Involved in vascular development. Regulator of macrophage adhesion and spreading. Positively affects cell-matrix adhesion. Positive regulator of platelet activation and thrombosis. Negative regulator of cell proliferation. Negative regulator of PDGF-stimulated cell migration; through dephosphorylation of PDGFR. Positive regulator of endothelial cell survival, as well as of VEGF-induced SRC and AKT activation; through KDR dephosphorylation. Negative regulator of EGFR signaling pathway; through EGFR dephosphorylation. Enhances the barrier function of epithelial junctions during reassembly. Negatively regulates T-cell receptor (TCR) signaling. Upon T-cell TCR activation, it is up-regulated and excluded from the immunological synapses, while upon T-cell-antigen presenting cells (APC) disengagement, it is no longer excluded and can dephosphorylate PLCG1 and LAT to down-regulate prolongation of signaling.                  
Publication Abstract from PubMed
Protein tyrosine phosphatases (PTPs) play a critical role in regulating cellular functions by selectively dephosphorylating their substrates. Here we present 22 human PTP crystal structures that, together with prior structural knowledge, enable a comprehensive analysis of the classical PTP family. Despite their largely conserved fold, surface properties of PTPs are strikingly diverse. A potential secondary substrate-binding pocket is frequently found in phosphatases, and this has implications for both substrate recognition and development of selective inhibitors. Structural comparison identified four diverse catalytic loop (WPD) conformations and suggested a mechanism for loop closure. Enzymatic assays revealed vast differences in PTP catalytic activity and identified PTPD1, PTPD2, and HDPTP as catalytically inert protein phosphatases. We propose a "head-to-toe" dimerization model for RPTPgamma/zeta that is distinct from the "inhibitory wedge" model and that provides a molecular basis for inhibitory regulation. This phosphatome resource gives an expanded insight into intrafamily PTP diversity, catalytic activity, substrate recognition, and autoregulatory self-association.
Large-scale structural analysis of the classical human protein tyrosine phosphatome.,Barr AJ, Ugochukwu E, Lee WH, King ON, Filippakopoulos P, Alfano I, Savitsky P, Burgess-Brown NA, Muller S, Knapp S Cell. 2009 Jan 23;136(2):352-63. PMID:19167335
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.