The human GRB2 and Drosophila Drk genes can functionally replace the Caenorhabditis elegans cell signaling gene sem-5

M. J. Stern, L. E.M. Marengere, R. J. Daly, E. J. Lowenstein, M. Kokel, A. Batzer, P. Olivier, T. Pawson, J. Schlessinger

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Mutations in the Caenorhabditis elegans gene sem-5 affect cell signaling processes involved in guiding a class of cell migrations and inducing vulval cell fates. The sem-5 sequence encodes a protein comprised almost exclusively of SH2 and SH3 domains (SH, src homology region) that are found together in many signaling proteins and nonreceptor tyrosine kinases. A human protein, GRB2, was identified by its ability to associate with the activated human epidermal growth factor receptor (hEGFR). The GRB2 and Sem-5 proteins share an identical architecture of their SH2 and SH3 domains and 58% amino acid sequence identity. Here we demonstrate that GRB2 and a Drosophila sem-5-like gene Drk can specifically rescue sem-5 mutants. We also show that Sem-5, like GRB2, can bind to the activated hEGFR in vitro. We further correlate the abilities of several mutant variants of GRB2 and Sem-5 to bind to the hEGFR in vitro with their abilities to functionally replace sem-5 in vivo. These data indicate that GRB2 and Drk are functional homologues of Sem-5 and demonstrate the high degree of conservation of both structure and function between signaling systems throughout evolution.

Original languageEnglish
Pages (from-to)1175-1188
Number of pages14
JournalMolecular Biology of the Cell
Issue number11
Publication statusPublished - 1 Jan 1993
Externally publishedYes

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