From Proteopediaproteopedia link
Protein tyrosine phosphatase 1B with sulfamic acid inhibitors
[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
High-throughput screening of the P&GP corporate repository against several protein tyrosine phosphatases identified the sulfamic acid moiety as potential phosphotyrosine mimetic. Incorporation of the sulfamic acid onto a 1,2,3,4-tetrahydroisoquinoline scaffold provided a promising starting point for PTP1B inhibitor design.
1,2,3,4-Tetrahydroisoquinolinyl sulfamic acids as phosphatase PTP1B inhibitors.,Klopfenstein SR, Evdokimov AG, Colson AO, Fairweather NT, Neuman JJ, Maier MB, Gray JL, Gerwe GS, Stake GE, Howard BW, Farmer JA, Pokross ME, Downs TR, Kasibhatla B, Peters KG Bioorg Med Chem Lett. 2006 Mar 15;16(6):1574-8. Epub 2006 Jan 4. PMID:16386905
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.