title: A putative Ras GTPase activating protein acts as a negative regulator of signaling by the Sevenless receptor tyrosine kinase.
abstract: A Drosophila gene with similarity to the mammalian Ras GTPase activating protein has been isolated in screens for mutations that affect eye development. Inactivation of the locus, Gap1, mimics constitutive activation of the Sevenless receptor tyrosine kinase and eliminates the need for a functional Sevenless protein in the R7 cell. Our results suggest that Gap1 acts as a negative regulator of signaling by Sevenless by down-regulating the activity of the Ras1 protein, which has been shown to be a key element in signaling by Sevenless.
authors.affiliation: Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720.
authors.forename: U
authors.initials: U
authors.lastname: Gaul
authors.forename: G
authors.initials: G
authors.lastname: Mardon
authors.forename: G M
authors.initials: GM
authors.lastname: Rubin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015536:Down-Regulation / Q000235:genetics; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics*; D005123:Eye / Q000196:embryology; D005136:Eye Proteins / Q000378:metabolism; D020690:GTPase-Activating Proteins; D005786:Gene Expression Regulation / Q000235:genetics; D005809:Genes, Regulator / Q000235:genetics*; D011905:Genes, ras; D008562:Membrane Glycoproteins / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011506:Proteins / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases; D016415:Sequence Alignment; D015398:Signal Transduction / Q000235:genetics; D020703:ras GTPase-Activating Proteins
chemical_list: D029721:Drosophila Proteins; D005136:Eye Proteins; D020690:GTPase-Activating Proteins; D008562:Membrane Glycoproteins; D011506:Proteins; D020703:ras GTPase-Activating Proteins; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; C056737:sev protein, Drosophila