title: Differential utilization of ShcA tyrosine residues and functional domains in the transduction of epidermal growth factor-induced mitogen-activated protein kinase activation in 293T cells and nerve growth factor-induced neurite outgrowth in PC12 cells. Identification of a new Grb2.Sos1 binding site.
abstract: By transient expression of both truncated forms of p52(SHCA) and those with point mutations in 293T cells, it has been shown that, in addition to Tyr-317, Tyr-239/240 is a major site of phosphorylation that serves as a docking site for Grb2.Sos1 complexes. In addition, analysis of epidermal growth factor (EGF)-induced activation of mitogen-activated protein kinase in 293T cells showed that the overexpression Shc SH2 or phosphotyrosine binding (PTB) domains of ShcA alone has a more potent negative effect than the overexpression of the forms of ShcA lacking Tyr-317 or Tyr 239/240 or both. In transiently transfected PC12 cells, the ShcA PTB domain and tyrosine phosphorylation in the CH1 domain, especially on Tyr-239/240, are crucial for mediating nerve growth factor (NGF)-induced neurite outgrowth. These findings suggest that the EGF and NGF (TrkA) receptor can utilize Shc in different ways to promote their activity. For EGF-induced mitogen-activated protein kinase activation in 293T cells, both Shc PTB and SH2 domains are essential for optimal activation, indicating that a mechanism independent of Grb2 engagement with Shc may exist. For NGF-induced neurite outgrowth in PC12 cells, Shc PTB plays an essential role, and phosphorylation on Tyr-239/240, but not on Tyr-317, is required.
authors.affiliation: Department of Physiology and Biophysics, University of California, Irvine, California 92697, USA.
authors.forename: D
authors.initials: D
authors.lastname: Thomas
authors.forename: R A
authors.initials: RA
authors.lastname: Bradshaw
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D001665:Binding Sites; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002455:Cell Division; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000378:metabolism*; D051380:GRB2 Adaptor Protein; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D016296:Mutagenesis; D009414:Nerve Growth Factors / Q000494:pharmacology*; D016501:Neurites / Q000187:drug effects*; D016716:PC12 Cells; D011494:Protein Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D055765:Shc Signaling Adaptor Proteins; D020664:Son of Sevenless Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine / Q000378:metabolism*; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C495950:Grb2 protein, rat; D008565:Membrane Proteins; D009414:Nerve Growth Factors; D011506:Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528035:Shc1 protein, rat; D020664:Son of Sevenless Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine; D004815:Epidermal Growth Factor; D011494:Protein Kinases; D066246:ErbB Receptors; D017871:Calcium-Calmodulin-Dependent Protein Kinases