Allele-specific suppression of a Saccharomyces cerevisiae prp20 mutation by overexpression of a nuclear serine/threonine protein kinase.
The yeast PRP20 protein is homologous to the RCC1 protein of higher eukaryotes and is required for mRNA export and maintenance of nuclear structure. RCC1/PRP20 act as guanine nucleotide exchange factors for the nuclear Ras-like Ran/GSP1 proteins. In a search for prp20-10 allele-specific high-copy-number suppressors, the KSP1 locus, encoding a serine/threonine protein kinase was isolated. Ksp1p is a nuclear protein that is not essential for vegetative growth of yeast. Inactivation of the kinase activity by a mutation affecting the catalytic center of the Ksp1p eliminated the suppressing activity. Based on the isolation of a protein kinase as a high-copy-number suppressor, the phosphorylation of Prp20p was examined. In vivo labeling experiments showed that Prp20p is a phosphoprotein; however, deletion of the KSP1 kinase did not affect Prp20p phosphorylation.
Fleischmann
M
M
Mikrobiologisches Institut, ETH Zürich, Zürich, Switzerland.
Stagljar
I
I
Aebi
M
M
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000201:enzymology*; D004268:DNA-Binding Proteins / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D015870:Gene Expression; D020662:Guanine Nucleotide Exchange Factors; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000235:genetics*; D010957:Plasmids; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000235:genetics*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D020662:Guanine Nucleotide Exchange Factors; D009687:Nuclear Proteins; C067050:SRM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017346:Protein Serine-Threonine Kinases