Mutation of Tyrosine 960 within the insulin receptor juxtamembrane domain impairs glucose transport but does not inhibit ligand-mediated phosphorylation of insulin receptor substrate-2 in 3T3-L1 adipocytes

Oleg V. Chaika, Nina Chaika, Deanna J. Volle, Hideki Hayashi, Yousuke Ebina, Ling Mei Wang, Jacalyn H. Pierce, Robert E Lewis

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Abstract

CSF-1 is equipotent to insulin in its ability to stimulate 2- [3H]deoxyglucose uptake in 3T3-L1 adipocytes expressing the colony stimulating factor-1 receptor/insulin receptor chimera (CSF1R/IR). However, CSF-1-stimulated glucose uptake and glycogen synthesis is reduced by 50% in comparison to insulin in 3T3-L1 cells expressing a CSF1R/IR mutated at Tyr960 (CSF1R/IRA960). CSF-1-treated adipocytes expressing the CSF1R/IRA960 were impaired in their ability to phosphorylate insulin receptor substrate 1 (IRS-1) but not in their ability to phosphorylate IRS-2. Immunoprecipitation of IRS proteins followed by Western blotting revealed that the intact CSF1R/IR co-precipitates with IRS-2 from CSF-1-treated cells. In contrast, the CSF1R/IRA960 co-precipitates poorly with IRS-2. These observations suggest that Tyr960 is important for interaction of the insulin receptor cytoplasmic domain with IRS-2, but it is not essential to the ability of the insulin receptor tyrosine kinase to use IRS-2 as a substrate. These observations also suggest that in 3T3-L1 adipocytes, tyrosine phosphorylation of IRS-2 by the insulin receptor tyrosine kinase is not sufficient for maximal stimulation of receptor-regulated glucose transport or glycogen synthesis.

Original languageEnglish (US)
Pages (from-to)12075-12080
Number of pages6
JournalJournal of Biological Chemistry
Volume274
Issue number17
DOIs
Publication statusPublished - Apr 23 1999

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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