Kinetic properties of Ash/Grb2-interacting GDP/GTP exchange protein.
Ash/Grb2 is a protein having one SH2 domain flanked by two SH3 domains and is implicated to serve as an adaptor protein which links the EGF receptor to mammalian Sos (mSos), a GDP/GTP exchange protein for Ras. We isolated here several Ash-interacting proteins from bovine brain cytosol by use of glutathione-S-transferase-Ash-linked agarose column chromatography. The Ash-interacting proteins stimulated the GDP/GTP exchange reaction of Ki-Ras and Ha-Ras but not that of other small GTP-binding proteins including at least Rap1, RhoA, Rac1, and Rab3A. The Ash-interacting proteins were much more active on the post-translationally lipid-modified form of Ki-Ras than on the unmodified form. At least one of them was identified as mSos by Western blot analysis using a specific anti-mSos antibody.
Nakanishi
H
H
Department of Biochemistry, Kobe University School of Medicine, Japan.
Orita
S
S
Kaibuchi
K
K
Miura
K
K
Miki
H
H
Takenawa
T
T
Takai
Y
Y
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D002846:Chromatography, Affinity; D003600:Cytosol / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D051380:GRB2 Adaptor Protein; D019204:GTP-Binding Proteins / Q000378:metabolism*; D011905:Genes, ras; D005982:Glutathione Transferase; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007700:Kinetics; D015689:Oncogene Protein p21(ras) / Q000378:metabolism; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism*; D013997:Time Factors; D014316:Tritium; D020692:rab3 GTP-Binding Proteins; D020744:rac GTP-Binding Proteins; D020668:rap GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein
D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; D011506:Proteins; D014316:Tritium; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D005982:Glutathione Transferase; D066246:ErbB Receptors; D019204:GTP-Binding Proteins; D015689:Oncogene Protein p21(ras); D020692:rab3 GTP-Binding Proteins; D020744:rac GTP-Binding Proteins; D020668:rap GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein