Abstract
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.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Alleles
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Amino Acid Sequence
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Base Sequence
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Cell Nucleus / enzymology*
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DNA-Binding Proteins / genetics
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Fungal Proteins / genetics*
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Gene Expression*
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Guanine Nucleotide Exchange Factors
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Molecular Sequence Data
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Mutagenesis
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Nuclear Proteins / genetics*
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Plasmids
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Protein Serine-Threonine Kinases / biosynthesis*
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Protein Serine-Threonine Kinases / genetics*
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Restriction Mapping
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Saccharomyces cerevisiae / enzymology
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae Proteins*
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Schizosaccharomyces / enzymology
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Schizosaccharomyces / genetics
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Sequence Deletion
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Sequence Homology, Amino Acid
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Suppression, Genetic*
Substances
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DNA-Binding Proteins
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Fungal Proteins
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Guanine Nucleotide Exchange Factors
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Nuclear Proteins
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SRM1 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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Protein Serine-Threonine Kinases