Abstract
Exposure to mating pheromone in haploid Saccharomyces cerevisiae cells results in the arrest of the cell cycle, expression of mating-specific genes, and polarized growth toward the mating partner. Proteins involved in signaling, polarization, cell adhesion, and fusion are localized to the tip of the mating cell (shmoo) where fusion will eventually occur. The mechanisms ensuring the correct targeting and retention of these proteins are poorly understood. Here we show that in pheromone-treated cells, a reorganization of the plasma membrane involving lipid rafts results in the retention of proteins at the tip of the mating projection, segregated from the rest of the membrane. Sphingolipid and ergosterol biosynthetic mutants fail to polarize proteins to the tip of the shmoo and are deficient in mating. Our results show that membrane microdomain clustering at the mating projection is involved in the generation and maintenance of polarity during mating.
MeSH terms
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Acyltransferases / genetics
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Acyltransferases / metabolism
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Adaptor Proteins, Signal Transducing*
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Amino Acid Transport Systems*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cell Membrane / metabolism
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Fungal Proteins / genetics
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Fungal Proteins / metabolism*
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Glucose Transport Proteins, Facilitative
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Mating Factor
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Membrane Microdomains / metabolism*
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Methyltransferases / genetics
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Methyltransferases / metabolism
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Monosaccharide Transport Proteins / genetics
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Monosaccharide Transport Proteins / metabolism
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Peptides / metabolism*
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Phosphoric Monoester Hydrolases / genetics
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Phosphoric Monoester Hydrolases / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae / physiology*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Serine C-Palmitoyltransferase
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Ubiquitin-Protein Ligases
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ras GTPase-Activating Proteins / genetics
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ras GTPase-Activating Proteins / metabolism
Substances
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Adaptor Proteins, Signal Transducing
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Amino Acid Transport Systems
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BUL1 protein, S cerevisiae
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BUL2 protein, S cerevisiae
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Carrier Proteins
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FUS1 protein, S cerevisiae
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Fungal Proteins
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GAP1 protein, S cerevisiae
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Glucose Transport Proteins, Facilitative
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HXT2 protein, S cerevisiae
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Membrane Proteins
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Monosaccharide Transport Proteins
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Peptides
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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ras GTPase-Activating Proteins
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Mating Factor
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Methyltransferases
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delta 24-sterol methyltransferase
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Acyltransferases
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Serine C-Palmitoyltransferase
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Ubiquitin-Protein Ligases
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LCB3 protein, S cerevisiae
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Phosphoric Monoester Hydrolases