title: Knock-down of LAR protein tyrosine phosphatase induces insulin resistance.
abstract: To test the role of the leukocyte common antigen-related protein tyrosine phosphatase (LAR) as a regulator of insulin receptor (IR) signalling, an siRNA probe against LAR was developed. Knock-down of LAR induced post-receptor insulin resistance with the insulin-induced activation of PKB/Akt and MAP kinases markedly inhibited. The phosphorylation and dephosphorylation of the IR and insulin receptor substrate (IRS) proteins were unaffected by LAR knock-down. These results identify LAR as a crucial regulator of the sensitivity of two key insulin signalling pathways to insulin. Moreover, the siRNA probe provides a molecular tool of general applicability for further dissecting the precise targets and roles of LAR.
authors.affiliation: School of Biological Sciences, Biomedical Sciences Building, University of Southampton, Bassett Crescent East, Southampton, SO16 7PX, UK.
authors.forename: Ann
authors.initials: A
authors.lastname: Mander
authors.forename: Conrad P
authors.initials: CP
authors.lastname: Hodgkinson
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Sale
mesh_terms: D002460:Cell Line; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007333:Insulin Resistance / Q000235:genetics*; D019000:Phosphotyrosine / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; D011956:Receptors, Cell Surface / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013379:Substrate Specificity
chemical_list: D007328:Insulin; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D019000:Phosphotyrosine; D011972:Receptor, Insulin; C516841:PTPRA protein, human; D017027:Protein Tyrosine Phosphatases; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4