title: Characterization of the phosphotyrosine-binding domain of the Drosophila Shc protein.
abstract: The phosphotyrosine-binding (PTB) domain of Drosophila Shc (dShc) binds in vitro to phosphopeptides containing the sequence motif NPXpY, and physically associates with the activated Drosophila epidermal growth factor receptor homologue (DER) in vivo. The structural elements, specificity and binding kinetics of the dShc PTB domain have now been characterized. The dShc PTB domain appeared similar to the insulin-like receptor substrate-1 PTB domain in secondary structure as suggested by Fourier transform infrared spectroscopy. Surface plasmon resonance measurements indicated that the dShc PTB domain bound with high affinity to phosphopeptides (Der) derived from the Tyr1228 site of the DER receptor. The kinetics of the dShc PTB domain-Der phosphopeptide interaction differed from those of a typical SH2 domain-ligand interaction, in that the PTB domain displayed slower on/off rates. Competition binding assays using truncated versions of the Der peptides revealed that high affinity binding to the dShc PTB domain requires, in addition to the NPXpY motif, the presence of hydrophobic residues at both positions -5 and -7 relative to phosphotyrosine. The dShc PTB domain showed a similar binding specificity to the human Shc (hShc) PTB domain, but subtle differences were noted; such that the hShc PTB domain bound preferentially to a phosphopeptide from the mammalian nerve growth factor receptor, whereas the dShc PTB domain bound preferentially to phosphopeptides from the Drosophila DER receptor. The invertebrate dShc PTB domain therefore possesses a binding specificity for tyrosine-phosphorylated peptides that is optimally suited for recognition of the activated DER receptor.
authors.affiliation: Program in Molecular Biology and Cancer, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada. pawson@mshri.on.ca
authors.forename: S C
authors.initials: SC
authors.lastname: Li
authors.forename: K M
authors.initials: KM
authors.lastname: Lai
authors.forename: G D
authors.initials: GD
authors.lastname: Gish
authors.forename: W E
authors.initials: WE
authors.lastname: Parris
authors.forename: P
authors.initials: P
authors.lastname: van der Geer
authors.forename: J
authors.initials: J
authors.lastname: Forman-Kay
authors.forename: T
authors.initials: T
authors.lastname: Pawson
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D004330:Drosophila; D029721:Drosophila Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D019000:Phosphotyrosine / Q000378:metabolism*; D011494:Protein Kinases; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D018010:Receptors, Invertebrate Peptide / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D017550:Spectroscopy, Fourier Transform Infrared; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D029721:Drosophila Proteins; D011506:Proteins; D018010:Receptors, Invertebrate Peptide; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D019000:Phosphotyrosine; D011494:Protein Kinases; C066532:Egfr protein, Drosophila; D066246:ErbB Receptors