Replacement of the conserved tyrosine 1210 by phenylalanine in the insulin receptor affects insulin-induced dephosphorylation of focal adhesion kinase but leaves other responses intact
| Autor: | J. Dorrestijn, J. A. Maassen, D. M. Ouwens, Van der Zon Gc |
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| Rok vydání: | 1996 |
| Předmět: |
Phenylalanine
Molecular Sequence Data CHO Cells Biochemistry Tropomyosin receptor kinase C Receptor tyrosine kinase Phosphatidylinositol 3-Kinases Insulin receptor substrate Cricetinae Animals Insulin Amino Acid Sequence Tyrosine Phosphorylation Conserved Sequence DNA Primers biology Base Sequence Kinase Temperature Protein-Tyrosine Kinases Phosphoproteins IRS2 Receptor Insulin Enzyme Activation Insulin receptor Phosphotransferases (Alcohol Group Acceptor) Focal Adhesion Protein-Tyrosine Kinases biology.protein Insulin Receptor Substrate Proteins Mutagenesis Site-Directed Tyrosine kinase Cell Adhesion Molecules Glycogen Protein Binding |
| Zdroj: | Biochemistry. 35(32) |
| ISSN: | 0006-2960 |
| Popis: | The families of tyrosine and serine/threonine kinases exhibit shared clusters of conserved amino acid residues. Some conserved residues are confined to the family of tyrosine kinases (TKs), like Tyr at position 1210 in the insulin receptor. Nearly all TKs have at this position Tyr, whereas Ser/Thr kinases generally have Phe at this site. The three-dimensional structure of the insulin receptor TK domain shows Tyr1210 to be located in the cleft, below bound ATP, in a region which potentially contributes to substrate binding. We have examined whether this specific Tyr residue contributes to the generation of TK-specific responses, such as Tyr phosphorylation of Shc, activation of Ras and Erk1,2, and stimulation of DNA synthesis. In addition, we have examined the contribution of Tyr1210 to insulin receptor-specific responses as Tyr phosphorylation of IRS1, stimulation of glycogen synthesis, and dephosphorylation of focal adhesion kinase (FAK). Wild-type and a mutant insulin receptor, in which Tyr1210 was replaced by Phe, were stably expressed in CHO cells, and clones expressing similar numbers of insulin receptors were selected. It was found that replacement of Tyr1210 by Phe resulted in a receptor which was nearly inactive in inducing dephosphorylation of FAK. The mutant receptor was able to induce RasGTP formation, glycogen synthesis, and activation of phosphatidylinositol 3-kinase, though the magnitude of stimulation of some responses was decreased. These findings indicate that Tyr1210 is not essential for the induction of tyrosine kinase-specific responses, such as activation of the Shc/Ras/Erk1,2 pathway and mitogenicity. On the other hand, the abrogation of insulin-induced FAK dephosphorylation indicates that Tyr1210 is involved in coupling of the activated receptor to some downstream targets. Thus, Tyr1210 may fine tune the signal generated by the activated insulin receptor. |
| Databáze: | OpenAIRE |
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