The dominant negative effect of a kinase-defective insulin receptor on insulin-like growth factor-I-stimulated signaling in Rat-1 fibroblasts

Metabolism: Clinical and Experimental
Y TakataM Kobayashi

Abstract

To study the interaction between insulin receptor (IR) and insulin-like growth factor-I (IGF-I) receptor (IGF-IR) tyrosine kinases, we examined IGF-I action in Rat-1 cells expressing a naturally occurring tyrosine kinase-deficient mutant IR (Asp 1048 IR). IGF-I normally stimulated receptor autophosphorylation, IRS-I phosphorylation, and glycogen synthesis in cells expressing Asp 1048 IR. However, the Asp 1048 IR inhibited IGF-I-stimulated thymidine uptake by 45% to 52% and amino acid uptake (aminoisobutyric acid [AIB]) by 58% in Asp 1048 IR cells. Furthermore, IGF-I-stimulated tyrosine kinase activity toward synthetic polymers, Shc phosphorylation, and mitogen-activated protein (MAP) kinase activity was inhibited. The inhibition of mitogenesis and AIB uptake was restored with the amelioration of the impaired tyrosine kinase activity and Shc phosphorylation by the introduction of abundant wild-type IGF-IR in Asp 1048 IR cells. These results suggest that the Asp 1048 IR causes a dominant negative effect on IGF-IR in transmitting signals to Shc and MAP kinase activation, which leads to decreased IGF-I-stimulated DNA synthesis, and that the kinase-defective insulin receptor does not affect IGF-I-stimulated IRS-I phosphorylation, wh...Continue Reading

References

Apr 20, 1990·Cell·A Ullrich, J Schlessinger
Jan 1, 1985·Annual Review of Physiology·E R FroeschJ Zapf
Oct 1, 1982·The Journal of Clinical Endocrinology and Metabolism·P B Kaplowitz, A J D'Ercole
Jan 1, 1993·Recent Progress in Hormone Research·C R KahnP Huertas
Jan 6, 1995·The Journal of Biological Chemistry·B KublaouiP F Pilch

❮ Previous
Next ❯

Related Concepts

Related Feeds

Cell Signaling by Tyrosine Kinases

Receptor tyrosine kinases (RTKs) are the high-affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones. RTKs have been shown not only to be key regulators of normal cellular processes but also to have a critical role in the development and progression of many types of cancer. Discover the latest research on cell signaling and RTK here.