title: Functional coupling of the mammalian EGF receptor to the Ras/cAMP pathway in the yeast Saccharomyces cerevisiae.
abstract: Autophosphorylation of tyrosine residues on the cytoplasmic tail of the epidermal growth factor receptor (EGFR) upon ligand binding leads to recruitment of the Grb2/Sos complex to the activated receptor and to activation of the Ras pathway. The major aim of this study was to ascertain to which extent the EGFR module (receptor, Grb2, hSos1) could work in a lower eukaryote, completely devoid of tyrosine kinase receptors but possessing hortologues to mammalian Ras proteins. We show that the EGFR module can be functionally linked to the Ras/cAMP pathway in a Saccharomyces cerevisiae cdc25 ( ts ) strain, as monitored by several independent biological readouts, including drop of budding index, decrease of cAMP level and acquisition of thermotolerance. Autophosphorylation of the receptor is a necessary step for RTK-dependent activation of the yeast Ras pathway, since genetic and pharmacological downregulation of the EGFR catalytic activity abolish coupling with the Ras/cAMP pathway. Thus, our results newly indicate that a RTK-based signal transduction module can be functionally coupled to the yeast Ras/cAMP pathway and that our system can be a valuable tool for the screen of drugs inhibiting the kinase activity of the receptor.
authors.affiliation: Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Busti
authors.forename: Elena
authors.initials: E
authors.lastname: Sacco
authors.forename: Enzo
authors.initials: E
authors.lastname: Martegani
authors.forename: Marco
authors.initials: M
authors.lastname: Vanoni
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D051380:GRB2 Adaptor Protein / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D018869:Heat-Shock Response; D006801:Humans; D047468:Immunoprecipitation; D009584:Nitrogen / Q000378:metabolism; D010766:Phosphorylation; D020837:SOS1 Protein / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*; D020666:ras-GRF1 / Q000235:genetics / Q000378:metabolism
chemical_list: C542351:CDC25 protein, S cerevisiae; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D020837:SOS1 Protein; D029701:Saccharomyces cerevisiae Proteins; D020666:ras-GRF1; D004815:Epidermal Growth Factor; D000242:Cyclic AMP; D066246:ErbB Receptors; D018631:ras Proteins; D009584:Nitrogen