Phosphorylation state and biological function of a mutant human insulin receptor Val996.

摘要: Abstract Chinese hamster ovary (CHO) cell transfectants that expressed human insulin receptors whose glycine 996 was substituted by valine were studied. Receptor processing and binding unaffected this mutation; however, mutant receptor had little or no tyrosine kinase activity. Nevertheless, the Val996 exhibited seryl threonyl phosphorylation in both basal insulin-stimulated state intact cells. This is contrast to Lys----Ala1018 deficient (Russell, D. S., Gherzi, R., Johnson, E. L., Chou, C-K., Rosen, O. M. (1987) J. Biol. Chem. 262, 11833-11840). Cells expressing normal 10-fold more sensitive than untransfected CHO cells with respect of a cellular substrate (pp 185) on tyrosyl residues, glucose incorporation into glycogen, thymidine DNA, ribosomal protein S6. same sensitivity as Insulin rapidly internalized number surface decreased response exposure insulin. However, receptor, not significantly diminished It concluded despite occurrence phosphorylations, post-receptor effects described above are mediated kinase-deficient Val996.