title: A G protein gamma subunit shares homology with ras proteins.
abstract: Guanine nucleotide binding proteins (G proteins) that transduce signals from cell surface receptors to effector molecules are made up of three subunits, alpha, beta, and gamma. A complementary DNA clone that encodes a 71-amino acid protein was isolated from bovine brain; this protein contains peptide sequences that were derived from the purified gamma subunit of Gi and Go. The primary sequence of this G protein gamma subunit (G gamma) has 55 percent homology to the gamma subunit of transducin (T gamma) and also has homology to functional domains of mammalian ras proteins. The probe for isolating the clone was generated with the use of the polymerase chain reaction (PCR). The extent of divergence between T gamma and G gamma, the isolation of homologous PCR-generated fragments, and the differences between the predicted amino acid sequence of G gamma and that derived from the gamma subunit of Gi and Go indicate that gamma subunits are encoded by a family of genes.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena 91125.
authors.forename: N
authors.initials: N
authors.lastname: Gautam
authors.forename: M
authors.initials: M
authors.lastname: Baetscher
authors.forename: R
authors.initials: R
authors.lastname: Aebersold
authors.forename: M I
authors.initials: MI
authors.lastname: Simon
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D004259:DNA-Directed DNA Polymerase; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification; D005784:Gene Amplification; D051379:Mice; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012333:RNA, Messenger / Q000032:analysis; D012689:Sequence Homology, Nucleic Acid
chemical_list: D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D004259:DNA-Directed DNA Polymerase; D019204:GTP-Binding Proteins; D016283:Proto-Oncogene Proteins p21(ras)