From Proteopediaproteopedia link
CRYSTAL STRUCTURE OF PROTEIN TYROSINE PHOSPHATASE 1B COMPLEXED WITH 2-(OXALYL-AMINO)-4,5,6,7-TETRAHYDRO-THIENO[2,3-C]PYRIDINE-3-CARBOXYLIC ACID
[PTN1_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. 
Publication Abstract from PubMed
Several protein-tyrosine phosphatases (PTPs) have been proposed to act as negative regulators of insulin signaling. Recent studies have shown increased insulin sensitivity and resistance to obesity in PTP1B knockout mice, thus pointing to this enzyme as a potential drug target in diabetes. Structure-based design, guided by PTP mutants and x-ray protein crystallography, was used to optimize a relatively weak, nonphosphorus, nonpeptide general PTP inhibitor (2-(oxalyl-amino)-benzoic acid) into a highly selective PTP1B inhibitor. This was achieved by addressing residue 48 as a selectivity determining residue. By introducing a basic nitrogen in the core structure of the inhibitor, a salt bridge was formed to Asp-48 in PTP1B. In contrast, the basic nitrogen causes repulsion in other PTPs containing an asparagine in the equivalent position resulting in a remarkable selectivity for PTP1B. Importantly, this was accomplished while retaining the molecular weight of the inhibitor below 300 g/mol.
Structure-based design of a low molecular weight, nonphosphorus, nonpeptide, and highly selective inhibitor of protein-tyrosine phosphatase 1B.,Iversen LF, Andersen HS, Branner S, Mortensen SB, Peters GH, Norris K, Olsen OH, Jeppesen CB, Lundt BF, Ripka W, Moller KB, Moller NP J Biol Chem. 2000 Apr 7;275(14):10300-7. PMID:10744717
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.