title: A synthetic tris-sulfotyrosyl dodecapeptide analogue of the insulin receptor 1146-kinase domain inhibits tyrosine dephosphorylation of the insulin receptor in situ.
abstract: A synthetic tris-sulfotyrosyl dodecapeptide (TRDIY(S)ETDY(S)Y(S)RK-amide), whose primary sequence is identical to the 1142-1153 sequence of the insulin proreceptor, inhibited insulin receptor dephosphorylation in solubilized membranes, and digitonin-permeabilized cells derived from Chinese hamster ovary (CHO) cells expressing high levels of human insulin receptors (CHO/HIRc). It also inhibited the dephosphorylation of a synthetic tyrosine phosphorylated substrate by recombinant PTP-1B, a protein tyrosine phosphatase (PTPase), indicating that it acted via interaction with PTPase(s). A N-stearyl derivative of the peptide caused an approximately 4.5-fold increase in insulin-stimulated receptor autophosphorylaction in intact CHO/HIRc cells. The peptide displayed specificity toward tyrosine-class phosphatases only, as it had no effect on the activities of the serine/threonine phosphatases PP-1 and PP-2A, or alkaline phosphatase. The tyrosine sulfate ester bonds of the peptide were stable when incubated with PTP-1B (1 h, 30 degrees C). These data suggest that the sulfotyrosyl peptide functions as a nonhydrolyzable phosphotyrosyl peptide analogue capable of direct interaction with PTPase catalytic domain.
authors.affiliation: Diabetes Unit, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224.
authors.forename: A S
authors.initials: AS
authors.lastname: Liotta
authors.forename: H K
authors.initials: HK
authors.lastname: Kole
authors.forename: H M
authors.initials: HM
authors.lastname: Fales
authors.forename: J
authors.initials: J
authors.lastname: Roth
authors.forename: M
authors.initials: M
authors.lastname: Bernier
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002463:Cell Membrane Permeability; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011972:Receptor, Insulin / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D009842:Oligopeptides; D011994:Recombinant Proteins; C089321:tris-sulfotyrosyl dodecapeptide-I; D014443:Tyrosine; D011972:Receptor, Insulin; D000469:Alkaline Phosphatase; D010749:Phosphoprotein Phosphatases