ShcA tyrosine phosphorylation sites can replace ShcA binding in signalling by middle T-antigen.
ShcA and Grb2 are crucial components in signalling by most tyrosine kinase-associated receptors. How ever, it is not clear whether Grb2 bound directly to the receptor is equivalent to Grb2 associated via ShcA. We have used signalling stimulated by the middle T-antigen (MT) of polyoma virus to address this question. The two known Grb2-binding sites from murine ShcA, 313Y and 239/240YY, could functionally replace the MT ShcA-interacting region in transformation assays using Rat2 fibroblasts. This demonstrates that signal output from membrane-bound ShcA requires only these two sequences and the ShcA-binding site in MT does not recruit other signalling molecules. Two standard Grb2-interacting sequences, either from the EGF receptor or the ShcA 313Y region, could not replace the requirement for ShcA binding to MT, indicating an enhanced role for the ShcA 239/240YY motif. Sos1 and the docking protein Gab1 are brought into the MT complex through Grb2 association and this may be more effective using the 239/240YY sequence.
Nicholson
P R
PR
Department of Metabolic Medicine, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
Empereur
S
S
Glover
H R
HR
Dilworth
S M
SM
D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D051380:GRB2 Adaptor Protein; D051379:Mice; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D020837:SOS1 Protein / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; 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
D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C490897:Gab1 protein, mouse; C490896:Gab1 protein, rat; C495949:Grb2 protein, mouse; C495950:Grb2 protein, rat; D010750:Phosphoproteins; D011506:Proteins; D020837:SOS1 Protein; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine; D066246:ErbB Receptors