title: Reduction of protein-tyrosine phosphatase-1B increases insulin signaling in FAO hepatoma cells.
abstract: Protein-tyrosine phosphatase-1B (PTP1B) has been implicated as a negative regulator of insulin signaling. PTP1B dephosphorylates the insulin receptor and insulin receptor substrates (IRS-1/2), inhibiting the insulin-signaling pathway. PTP1B has been reported to be elevated in diabetes and insulin-resistant states. Conversely, PTP1B null mice have increased insulin sensitivity. To further investigate the effect of PTP1B reduction on insulin signaling, FAO rat hepatoma cells were transfected, by electroporation, with a specific PTP1B antisense oligonucleotide (ASO), or a control oligonucleotide. The PTP1B ASO caused a 50-70% reduction in PTP1B protein expression as measured by Western blot analysis. Upon insulin stimulation, an increase in the phosphorylation of the insulin receptor and insulin receptor substrates was observed, without any change in protein expression levels. Reduction of PTP1B expression in FAO cells also caused an increase in insulin-stimulated phosphorylation of PKB and GSK3, without any change in protein expression. These results demonstrate that reduction of PTP1B can modulate key insulin signaling events downstream of the insulin receptor.
authors.affiliation: Insulin Signaling, Metabolic Diseases Research, Global Pharmaceutical Research Division, Abbott Laboratories, Department 47R, Building AP10, 100 Abbott Park Road, Abbott Park, IL 60064-6009, USA.
authors.forename: Jill E
authors.initials: JE
authors.lastname: Clampit
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Meuth
authors.forename: Harriet T
authors.initials: HT
authors.lastname: Smith
authors.forename: Regina M
authors.initials: RM
authors.lastname: Reilly
authors.forename: Michael R
authors.initials: MR
authors.lastname: Jirousek
authors.forename: James M
authors.initials: JM
authors.lastname: Trevillyan
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Rondinone
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular; D004305:Dose-Response Relationship, Drug; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000235:genetics; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D011972:Receptor, Insulin / Q000378:metabolism; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
chemical_list: D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; C526295:Irs1 protein, mouse; C526296:Irs1 protein, rat; C526298:Irs2 protein, mouse; C526299:Irs2 protein, rat; D016376:Oligonucleotides, Antisense; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D011972:Receptor, Insulin; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D038362:Glycogen Synthase Kinase 3; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; C516610:Ptpn1 protein, rat