RGD Reference Report - Specific inhibition by hGRB10zeta of insulin-induced glycogen synthase activation: evidence for a novel signaling pathway. - Rat Genome Database

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Specific inhibition by hGRB10zeta of insulin-induced glycogen synthase activation: evidence for a novel signaling pathway.

Authors: Mounier, C  Lavoie, L  Dumas, V  Mohammad-Ali, K  Wu, J  Nantel, A  Bergeron, JJ  Thomas, DY  Posner, BI 
Citation: Mounier C, etal., Mol Cell Endocrinol. 2001 Feb 28;173(1-2):15-27.
RGD ID: 8553640
Pubmed: (View Article at PubMed) PMID:11223174

Grb10 is a member of a family of adapter proteins that binds to tyrosine-phosphorylated receptors including the insulin receptor kinase (IRK). In this study recombinant adenovirus was used to over-express hGrb10zeta, a new Grb10 isoform, in primary rat hepatocytes and the consequences for insulin signaling were evaluated. Over-expression of hGrb10zeta resulted in 50% inhibition of insulin-stimulated IRK autophosphorylation and activation. Analysis of downstream events showed that hGrb10zeta over-expression specifically inhibits insulin-stimulated glycogen synthase (GS) activity and glycogen synthesis without affecting insulin-induced IRS1/2 phosphorylation, PI3-kinase activation, insulin like growth factor binding protein-1 (IGFBP-1) mRNA expression, and ERK1/2 MAP kinase activity. The classical pathway from PI3-kinase through Akt-PKB/GSK-3 leading to GS activation by insulin was also not affected by hGrb10zeta over-expression. These results indicate that hGrb10zeta inhibits a novel and presently unidentified insulin signaling pathway leading to GS activation in liver.

Annotation

Gene Ontology Annotations    

Biological Process

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Grb10  (growth factor receptor bound protein 10)


Additional Information