Abstract
Protein kinases dedicated to the phosphorylation of SR proteins have been implicated in the processing and nuclear export of mRNAs. Here we demonstrate in Saccharomyces cerevisiae their participation in cation homeostasis. A null mutant of the single yeast SR protein kinase Sky1p is viable but exhibits increased tolerance to diverse toxic cations such as Na(+), Li(+), spermine, tetramethylammonium, hygromycin B and Mn(2+). This pleiotropic phenotype correlates with reduced accumulation of cations, suggesting a decrease in membrane electrical potential. Genetic analysis and Rb(+) uptake measurements indicate that Sky1p modulates Trk1,2, the high-affinity K(+) uptake system of yeast and a major determinant of membrane potential.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP-Binding Cassette Transporters / metabolism
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Cation Transport Proteins / genetics
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Cation Transport Proteins / metabolism*
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Lithium
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Manganese
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Membrane Potentials
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Mutation
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism*
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Protein-Arginine N-Methyltransferases*
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Repressor Proteins*
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Rubidium / metabolism*
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Saccharomyces cerevisiae / growth & development
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Signal Transduction
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Sodium
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Spermine
Substances
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ATP-Binding Cassette Transporters
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Cation Transport Proteins
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Repressor Proteins
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Saccharomyces cerevisiae Proteins
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TRK2 protein, S cerevisiae
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TRK1 protein, S cerevisiae
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Spermine
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Manganese
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Lithium
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Sodium
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HMT1 protein, S cerevisiae
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Protein-Arginine N-Methyltransferases
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SKY1 protein, S cerevisiae
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Protein Serine-Threonine Kinases
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Rubidium