Human growth factor receptor bound 14 binds the activated insulin receptor and alters the insulin-stimulated tyrosine phosphorylation levels of multiple proteins
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Date
2001-02-28
Authors
Hemming, R
Agatep, R
Badiani, K
Wyant, K
Arthur, G
Gietz, RD
Triggs-Raine, B
Journal Title
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Volume Title
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Abstract
To identify proteins interacting in the insulin-signaling pathway that might define new pathways or regulate existing ones, we have employed the yeast two-hybrid system. In a two-hybrid screen of a human liver cDNA library, we identified the human growth factor receptor bound 14 (hGrb14) adaptor protein as a partner of the activated insulin receptor. Additional analysis of the insulin receptor - hGrb14 interaction in the yeast two-hybrid system revealed that the SH2 domain of hGrb14 was not the sole region involved in binding the activated insulin receptor. The insulin-stimulated interaction between hGrb14 and the insulin receptor was also observed in different mammalian cultured cell lines. This association was detected at 1 min of insulin stimulation and was maximal at 10 nM and greater concentrations of insulin. Chinese hamster ovary cells stably expressing the insulin receptor (CHO-IR) and hGrb14 were used to examine the effects of hGrb14 overexpression on insulin-stimulated tyrosine phosphorylation of proteins; in general, increasing levels of hGrb14 expression resulted in a reduction in tyrosine phosphorylation. This decrease was demonstrated for the specific proteins src homology-containing and collagen-related protein (Shc), insulin receptor substrate-1 (IRS-1), and Downstream of tyrosine Kinase (Dok). The broad effects of hGrb14 overexpression on insulin-stimulated tyrosine phosphorylation suggest that it acts early in the insulin-signaling pathway.
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Keywords
insulin signaling, growth factor receptor bound 14, Grb14, adaptor protein, insulin receptor, FACTOR-I RECEPTOR, HIGH-EFFICIENCY TRANSFORMATION, SRC HOMOLOGY-2 DOMAIN, SH2 DOMAIN, PLECKSTRIN HOMOLOGY, ESCHERICHIA-COLI, 2-HYBRID SYSTEM, ADAPTER PROTEIN, KINASE DOMAIN, GRB-IR
Citation
0829-8211; BIOCHEM CELL BIOL, FEB 2001, vol. 79, no. 1, p.21 to 32.