Isolation of a second yeast Saccharomyces cerevisiae gene (GPA2) coding for guanine nucleotide-binding regulatory protein: studies on its structure and possible functions

• Published in: Proceedings of the National Academy of Sciences - PNAS 1988-03, Vol.85 (5), p.1374-1378
• Main Authors: Nakafuku, M, Obara, T, Kaibuchi, K, Miyajima, I, Miyajima, A, Itoh, H, Nakamura, S, Arai, K.I, Matsumoto, K, Kaziro, Y
• Format: Article
• Language: English
• Subjects: ACIDE AMINE; Amino Acid Sequence; AMINO ACIDS; AMINOACIDOS; Base Sequence; Biological and medical sciences; Chromosome Mapping; Cloning, Molecular; CODE GENETIQUE; CODIGO GENETICO; CONTENIDO PROTEICO; Cyclic AMP - physiology; DNA; DNA Mutational Analysis; Fundamental and applied biological sciences. Psychology; GENE; Gene Expression Regulation; Generally accepted auditing standards; GENES; Genes, Fungal; Genes. Genome; GENETIC CODE; GTP-Binding Proteins - genetics; Haploidy; LEVADURA; LEVURE; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; NUCLEOTIDE; NUCLEOTIDES; NUCLEOTIDOS; Open reading frames; Plasmids; PROTEIN CONTENT; RNA, Messenger - genetics; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - genetics; TENEUR EN PROTEINES; YEASTS
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.85.5.1374

In a previous paper, we demonstrated that a gene coding for a protein homologous to the α subunit of mammalian guanine nucleotide-binding regulatory (G) proteins occurs in Saccharomyces cerevisiae. The gene, designated GAP1, encodes a protein (GP1α ) of 472 amino acids with a calculated Mr of 54,075. Here we report the isolation of another G-protein-homologous gene, GPA2, which encodes an amino acid sequence of 449 amino acid residues with a Mr of 50,516. The predicted primary structure of the GPA2-encoded protein (GP2α ) is homologous to mammalian G proteins [inhibitory and stimulatory G proteins (Gi and Gs, respectively), a G protein of unknown function (Go), and transducins (Gt)] as well as yeast GP1α . When aligned with the α subunit of Gi (Giα) to obtain maximal homology, GP2α was found to contain a stretch of 83 additional amino acid residues near the NH2 terminus. The gene was mapped in chromosome V, close to the centromere. Haploid cells carrying a disrupted GPA2 gene are viable. Cells carrying a high copy number of plasmid GPA2 (YEpGPA2) had markedly elevated levels of cAMP and could suppress a temperature-sensitive mutation of RAS2. These results suggest that GPA2 may be involved in the regulation of cAMP levels in S. cerevisiae.