Cdc50p, a conserved endosomal membrane protein, controls polarized growth in Saccharomyces cerevisiae.
During the cell cycle of the yeast Saccharomyces cerevisiae, the actin cytoskeleton and the growth of cell surface are polarized, mediating bud emergence, bud growth, and cytokinesis. We identified CDC50 as a multicopy suppressor of the myo3 myo5-360 temperature-sensitive mutant, which is defective in organization of cortical actin patches. The ... cdc50 null mutant showed cold-sensitive cell cycle arrest with a small bud as reported previously. Cortical actin patches and Myo5p, which are normally localized to polarization sites, were depolarized in the cdc50 mutant. Furthermore, actin cables disappeared, and Bni1p and Gic1p, effectors of the Cdc42p small GTPase, were mislocalized in the cdc50 mutant. As predicted by its amino acid sequence, Cdc50p appears to be a transmembrane protein because it was solubilized from the membranes by detergent treatment. Cdc50p colocalized with Vps21p in endosomal compartments and was also localized to the class E compartment in the vps27 mutant. The cdc50 mutant showed defects in a late stage of endocytosis but not in the internalization step. It showed, however, only modest defects in vacuolar protein sorting. Our results indicate that Cdc50p is a novel endosomal protein that regulates polarized cell growth.
Mesh Terms:
Actins, Adaptor Proteins, Signal Transducing, Amino Acid Sequence, Carrier Proteins, Cell Cycle, Cell Division, Cell Membrane, Centrifugation, Density Gradient, Cytoskeleton, Endocytosis, Endosomal Sorting Complexes Required for Transport, Endosomes, Green Fluorescent Proteins, Immunoblotting, Luminescent Proteins, Mannosidases, Microscopy, Electron, Molecular Sequence Data, Mutation, Plasmids, Precipitin Tests, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid, Subcellular Fractions, Sucrose, Temperature, Vesicular Transport Proteins, alpha-Mannosidase, cdc42 GTP-Binding Protein, rab GTP-Binding Proteins
Actins, Adaptor Proteins, Signal Transducing, Amino Acid Sequence, Carrier Proteins, Cell Cycle, Cell Division, Cell Membrane, Centrifugation, Density Gradient, Cytoskeleton, Endocytosis, Endosomal Sorting Complexes Required for Transport, Endosomes, Green Fluorescent Proteins, Immunoblotting, Luminescent Proteins, Mannosidases, Microscopy, Electron, Molecular Sequence Data, Mutation, Plasmids, Precipitin Tests, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid, Subcellular Fractions, Sucrose, Temperature, Vesicular Transport Proteins, alpha-Mannosidase, cdc42 GTP-Binding Protein, rab GTP-Binding Proteins
Mol. Biol. Cell
Date: Feb. 01, 2003
PubMed ID: 12589066
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