Abstract
The yeast CDC1 gene encodes an essential protein that has been implicated in the regulation of cytosolic [Mn2+]. To identify factors that impinge upon Cdc1 or the Cdc1-dependent process, we isolated second-site suppressors of the conditional cdc1-1(Ts) growth defect. Recessive suppressors define 15 COS (CdcOne Suppressor) genes. Seven of the fifteen COS genes are required for biogenesis of the vacuole, an organelle known to sequester intracellular Mn2+. An eighth gene, COS16, encodes a vacuolar membrane protein that seems to be involved in Mn2+ homeostasis. These results suggest mutations that block vacuolar Mn2+ sequestration compensate for defects in Cdc1 function. Interestingly, Cdc1 is dispensable in a cos16delta deletion strain, and a cdc1delta cos16delta double mutant exhibits robust growth on medium supplemented with Mn2+. Thus, the single, essential function of Cdc1 is to regulate intracellular, probably cytosolic, Mn2+.
MeSH terms
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ADP-Ribosylation Factors
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Adaptor Proteins, Vesicular Transport
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Adenosine Triphosphatases*
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Aspartic Acid Endopeptidases / genetics
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Carboxypeptidases / metabolism
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Cathepsin A
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / physiology*
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Endosomal Sorting Complexes Required for Transport
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Fungal Proteins / genetics
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GTP-Binding Proteins / genetics
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Genes, Fungal
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Genes, Suppressor
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Homeostasis / physiology*
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Manganese / metabolism*
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Membrane Proteins / genetics
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Phenotype
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / physiology*
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Saccharomyces cerevisiae Proteins*
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Subcellular Fractions
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Temperature
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Vacuoles
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Vesicular Transport Proteins
Substances
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Adaptor Proteins, Vesicular Transport
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CDC1 protein, S cerevisiae
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Cell Cycle Proteins
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Endosomal Sorting Complexes Required for Transport
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Fungal Proteins
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Membrane Proteins
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PEP3 protein, S cerevisiae
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PEP5 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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VPS16 protein, S cerevisiae
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VPS4 protein, S cerevisiae
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Vesicular Transport Proteins
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Manganese
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Carboxypeptidases
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Cathepsin A
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Aspartic Acid Endopeptidases
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aspergillopepsin II
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Adenosine Triphosphatases
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GTP-Binding Proteins
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ADP-Ribosylation Factors