title: Conformation-sensing antibodies stabilize the oxidized form of PTP1B and inhibit its phosphatase activity.
abstract: Protein tyrosine phosphatase 1B (PTP1B) plays important roles in downregulation of insulin and leptin signaling and is an established therapeutic target for diabetes and obesity. PTP1B is regulated by reactive oxygen species (ROS) produced in response to various stimuli, including insulin. The reversibly oxidized form of the enzyme (PTP1B-OX) is inactive and undergoes profound conformational changes at the active site. We generated conformation-sensor antibodies, in the form of single-chain variable fragments (scFvs), that stabilize PTP1B-OX and thereby inhibit its phosphatase function. Expression of conformation-sensor scFvs as intracellular antibodies (intrabodies) enhanced insulin-induced tyrosyl phosphorylation of the β subunit of the insulin receptor and its substrate IRS-1 and increased insulin-induced phosphorylation of PKB/AKT. Our data suggest that stabilization of the oxidized, inactive form of PTP1B with appropriate therapeutic molecules may offer a paradigm for phosphatase drug development.
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
authors.forename: Aftabul
authors.initials: A
authors.lastname: Haque
authors.forename: Jannik N
authors.initials: JN
authors.lastname: Andersen
authors.forename: Annette
authors.initials: A
authors.lastname: Salmeen
authors.forename: David
authors.initials: D
authors.lastname: Barford
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Tonks
mesh_terms: D000906:Antibodies; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D010084:Oxidation-Reduction; D019151:Peptide Library; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D057127:Single-Chain Antibodies / Q000737:chemistry
chemical_list: D000906:Antibodies; D019151:Peptide Library; D057127:Single-Chain Antibodies; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1