The class C Vps complex functions at multiple stages of the vacuolar transport pathway.
The Class C Vps complex, consisting of Vps11, Vps16, Vps18, and Vps33, is required for SNARE-mediated membrane fusion at the lysosome-like yeast vacuole. However, Class C vps mutants display more severe and pleiotropic phenotypes than mutants specifically defective in endosome-to-vacuole transport, suggesting that there are additional functions for the Class C Vps complex. A SNARE double mutant which is defective for both Golgi-to-endosome and endosome-to-vacuole trafficking replicates many of the phenotypes observed in Class C vps mutants. We show that genetic interactions exist between Class C vps alleles and alleles of the Class D vps group, which are defective in the docking and fusion of Golgi-derived vesicles at the endosome. Moreover, the Class D protein Vac1 was found to physically bind to the Class C Vps complex through a direct association with Vps11. Finally, using a random mutagenic screen, a temperature-conditional allele which shares many of the phenotypes of mutants which are selectively defective in Golgi-to-endosome trafficking was isolated (vps11-3ts). Collectively, these results indicate that the Class C Vps complex plays essential roles in the processes of membrane docking and fusion at both the Golgi-to-endosome and endosome-to-vacuole stages of transport.
Peterson
M R
MR
Division of Cellular and Molecular Medicine and Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California 92093-0668, USA.
Emr
S D
SD
D033942:Adaptor Proteins, Vesicular Transport; D000483:Alleles; D002352:Carrier Proteins; D011992:Endosomes / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005838:Genotype; D006056:Golgi Apparatus / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014617:Vacuoles / Q000378:metabolism*; D033921:Vesicular Transport Proteins; D016335:Zinc Fingers
D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D005656:Fungal Proteins; D008565:Membrane Proteins; C071657:PEP3 protein, S cerevisiae; C065710:PEP5 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C080045:VPS16 protein, S cerevisiae; C065454:VPS33 protein, S cerevisiae; D033921:Vesicular Transport Proteins