title: Networks of interaction of p120cbl and p130cas with Crk and Grb2 adaptor proteins.
abstract: P120cbl, the product of the c-cbl proto-oncogene, has previously been shown to become tyrosine phosphorylated following EGF stimulation of cells, and to bind constitutively to the SH3 domain of the adaptor protein Grb2. Here we show that another adaptor protein, Crk, binds through its SH2 domain to tyrosine phosphorylated p120cbl. In addition, Crk becomes phosphorylated on tyrosine and serine following EGF treatment of PC12 and other cell lines. In unstimulated cells, while Grb2 is not bound to any tyrosine phosphoprotein, Crk is bound via its SH2 domain to tyrosine phosphorylated p130cas, the Crk-associated v-Src substrate. Following EGF treatment, Crk dissociates from p130cas, possibly due to a higher affinity of Crk SH2 for p120cbl compared with p130cas. Interaction between Grb2 and p120cbl increases threefold following EGF treatment of cells; in vitro, this induction of Grb2 association with unphosphorylated p120cbl can be mimicked by the addition of tyrosine phosphorylated Shc, suggesting a transfer of information between the SH2 and SH3 domains of Grb2. These data indicate that adaptor proteins can exchange binding partners in response to stimuli, and that different adaptor proteins can bind to the same partners by different mechanisms.
authors.affiliation: Imperial Cancer Research Fund, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Khwaja
authors.forename: B
authors.initials: B
authors.lastname: Hallberg
authors.forename: P H
authors.initials: PH
authors.lastname: Warne
authors.forename: J
authors.initials: J
authors.lastname: Downward
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D001665:Binding Sites; D051177:Catenins; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D050719:Crk-Associated Substrate Protein; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D051380:GRB2 Adaptor Protein; D050736:Oncogene Protein v-crk; D015513:Oncogene Proteins / Q000378:metabolism*; D016716:PC12 Cells / Q000187:drug effects; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D011506:Proteins / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D050717:Retinoblastoma-Like Protein p130; D015682:Retroviridae Proteins, Oncogenic / Q000187:drug effects / Q000378:metabolism*; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains; D000095002:Delta Catenin
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; C493843:Bcar1 protein, rat; D051177:Catenins; D015815:Cell Adhesion Molecules; D050719:Crk-Associated Substrate Protein; D051380:GRB2 Adaptor Protein; C495950:Grb2 protein, rat; D050736:Oncogene Protein v-crk; D015513:Oncogene Proteins; D010750:Phosphoproteins; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D015682:Retroviridae Proteins, Oncogenic; D055765:Shc Signaling Adaptor Proteins; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine; D004815:Epidermal Growth Factor; D000095002:Delta Catenin