Mutation of a Shc binding site tyrosine residue in ErbB3/HER3 blocks heregulin-dependent activation of mitogen-activated protein kinase.

The ErbB2 and ErbB3 proteins together constitute a functional coreceptor for heregulin (neuregulin). Heregulin stimulates the phosphorylation of both coreceptor constituents and initiates a variety of other signaling events, which include phosphorylation of the Shc protein. The role of Shc in heregulin-stimulated signal transduction through the ErbB2.ErbB3 coreceptor was investigated ...
here. Heregulin was found to promote ErbB3/Shc association in NIH-3T3 cells expressing endogenous ErbB2 and recombinant ErbB3. A mutant ErbB3 protein was generated in which Tyr-1325 in a consensus Shc phosphotyrosine-binding domain recognition site was mutated to Phe (ErbB3-Y/F). This mutation abolished the association of Shc with ErbB3 and blocked the activation of mitogen-activated protein kinase by heregulin. Whereas heregulin induced mitogenesis in NIH-3T3 cells transfected with wild-type ErbB3 cDNA, this mitogenic response was markedly attenuated in NIH-3T3 cells transfected with the ErbB3-Y/F cDNA. These results showed a specific interaction of Shc with the ErbB3 receptor protein and demonstrated the importance of this interaction in the activation of mitogenic responses by the ErbB2. ErbB3 heregulin coreceptor complex.
Mesh Terms:
1-Phosphatidylinositol 3-Kinase, 3T3 Cells, Androstadienes, Animals, Base Sequence, Calcium-Calmodulin-Dependent Protein Kinases, Carrier Proteins, DNA Primers, DNA Replication, Enzyme Activation, Enzyme Inhibitors, Glycoproteins, Mice, Mutagenesis, Site-Directed, Neuregulin-1, Phosphorylation, Proto-Oncogene Proteins, Rats, Receptor, Epidermal Growth Factor, Receptor, erbB-3, Signal Transduction, Thymidine, Transfection, Tritium, Tyrosine
J. Biol. Chem.
Date: Aug. 14, 1998
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