Title: | Isolation and characterization of S. cerevisiae mutants defective in somatostatin expression: cloning and functional role of a yeast gene encoding an aspartyl protease in precursor processing at monobasic cleavage sites |
Author(s): | Bourbonnais Y; Ash J; Daigle M; Thomas DY; |
Address: | "National Research Council of Canada, Biotechnology Research Institute, Montreal, Quebec" |
DOI: | 10.1002/j.1460-2075.1993.tb05655.x |
ISSN/ISBN: | 0261-4189 (Print) 1460-2075 (Electronic) 0261-4189 (Linking) |
Abstract: | "The peptide somatostatin exists as two different molecular species. In addition to the most common form, somatostatin-14, there is also a fourteen amino acid N-terminally extended form of the tetradecapeptide, somatostatin-28. Both peptides are synthesized as larger precursors containing paired basic and monobasic amino acids at their processing sites, which upon cleavage generate either somatostatin-14 or -28, respectively. In some species of fish two distinct, but homologous, precursors (prosomatostatin-I and -II) give rise to somatostatin-14 and -28, respectively. Whereas anglerfish prosomatostatin-II was previously shown to release exclusively somatostatin-28, the yeast Saccharomyces cerevisiae proteolytically matures the homologous prosomatostatin-I precursor to somatostatin-28 and -14 as well as to a lysine-extended form of somatostatin-14. The Kex2 endoprotease appears to be essential for the formation of lysine somatostatin-14 and is involved either directly or indirectly in the release of mature somatostatin-14. The isolation of yeast mutants defective in somatostatin-28 expression (sex mutant) allowed the cloning of a non-essential gene, which encodes an aspartyl protease, whose disruption severely affects the cleavage of mature somatostatin-28 from both somatostatin precursors. We conclude that two distinct endoproteases, which demonstrate some cross specificity in vivo, are involved in the proteolytic maturation of prosomatostatin at mono- and dibasic processing sites in yeast" |
Keywords: | "Amino Acid Sequence Animals Aspartic Acid Endopeptidases/*genetics/*metabolism Cloning, Molecular Fishes *Genes, Fungal Mating Factor Molecular Sequence Data Mutagenesis Mutagenesis, Site-Directed Peptide Biosynthesis Peptides/genetics Pheromones/genetics;" |
Notes: | "MedlineBourbonnais, Y Ash, J Daigle, M Thomas, D Y eng England 1993/01/01 EMBO J. 1993 Jan; 12(1):285-94. doi: 10.1002/j.1460-2075.1993.tb05655.x" |