From Proteopediaproteopedia link
Crystal structure of PTP1B with monocyclic thiophene inhibitor
[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
A series of monocyclic thiophenes was designed and synthesized as PTP1B inhibitors. Guided by X-ray co-crystal structural information and computational modeling, rational design led to key interactions with Asp48 and improved inhibitory potency against PTP1B.
Monocyclic thiophenes as protein tyrosine phosphatase 1B inhibitors: capturing interactions with Asp48.,Wan ZK, Lee J, Xu W, Erbe DV, Joseph-McCarthy D, Follows BC, Zhang YL Bioorg Med Chem Lett. 2006 Sep 15;16(18):4941-5. Epub 2006 Jun 27. PMID:16806920
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.