A snc1 endocytosis mutant: phenotypic analysis and suppression by overproduction of dihydrosphingosine phosphate lyase.
The v-SNARE proteins Snc1p and Snc2p are required for fusion of secretory vesicles with the plasma membrane in yeast. Mutation of a methionine-based sorting signal in the cytoplasmic domain of either Sncp inhibits Sncp endocytosis and prevents recycling of Sncp to the Golgi after exocytosis. snc1-M43A mutant yeast have reduced growth and secretion rates and accumulate post-Golgi secretory vesicles and fragmented vacuoles. However, cells continue to grow and secrete for several hours after de novo Snc2-M42A synthesis is repressed. DPL1, the structural gene for dihydrosphingosine phosphate lyase, was selected as a high copy number snc1-M43A suppressor. Because DPL1 also partially suppresses the growth and secretion phenotypes of a snc deletion, we propose that enhanced degradation of dihydrosphingosine-1-phosphate allows an alternative protein to replace Sncp as the secretory vesicle v-SNARE.
Grote
E
E
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8002, USA.
Vlacich
G
G
Pypaert
M
M
Novick
P J
PJ
D000446:Aldehyde-Lyases / Q000235:genetics / Q000502:physiology*; D002455:Cell Division; D004705:Endocytosis; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D017353:Gene Deletion; D018628:Gene Dosage; D005800:Genes, Fungal; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D021381:Protein Transport; D050683:R-SNARE Proteins; D050600:SNARE Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins; D022142:Secretory Vesicles / Q000378:metabolism; D033921:Vesicular Transport Proteins
D005656:Fungal Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D050683:R-SNARE Proteins; D050600:SNARE Proteins; C083241:SNC1 protein, S cerevisiae; C083242:SNC2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D000446:Aldehyde-Lyases; C022649:sphingosine 1-phosphate lyase (aldolase)