title: Protein tyrosine phosphatase 1B is impaired in skeletal muscle of diabetic Psammomys obesus.
abstract: Protein tyrosine phosphatases (PTPases) have been suggested to modulate the insulin receptor signal transduction pathways. We studied PTPases in Psammomys obesus, an animal model of nutritionally induced insulin resistance. No changes in the protein expression level of src homology PTPase 2 (SHP-2) (muscle, liver) or leukocyte antigen receptor (LAR) (liver) were detected. In contrast, the expression level of PTPase 1B (PTP 1B) in the skeletal muscle, but not in liver, was increased by 83% in the diabetic animals, compared with a diabetes-resistant line. However, PTP 1B-specific activity (activity/protein) significantly decreased (50% to 56%) in skeletal muscle of diabetic animals, compared with both the diabetes-resistant line and diabetes-prone animals. In addition, PTP 1B activity was inversely correlated to serum glucose level (r = -.434, P < .02). These findings suggest that PTP 1B, though overexpressed, is not involved in the susceptibility to insulin resistance in Psammomys obesus and is secondarily attenuated by hyperglycemia or other factors in the diabetic milieu.
authors.affiliation: Department of Molecular Signaling, Hagedorn Research Institute, Gentofte, Denmark.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Ehud
authors.initials: E
authors.lastname: Ziv
authors.forename: Eleazar
authors.initials: E
authors.lastname: Shafrir
authors.forename: Luitgard
authors.initials: L
authors.lastname: Mosthaf-Seedorf
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002460:Cell Line; D003920:Diabetes Mellitus / Q000201:enzymology* / Q000503:physiopathology; D004198:Disease Susceptibility; D005260:Female; D005849:Gerbillinae / Q000502:physiology*; D006801:Humans; D007333:Insulin Resistance; D008099:Liver / Q000201:enzymology; D008297:Male; D018482:Muscle, Skeletal / Q000201:enzymology*; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; C516607:PTPN1 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases