Multiple classes of yeast mutants are defective in vacuole partitioning yet target vacuole proteins correctly.
In Saccharomyces cerevisiae the vacuoles are partitioned from mother cells to daughter cells in a cell-cycle-coordinated process. The molecular basis of this event remains obscure. To date, few yeast mutants had been identified that are defective in vacuole partitioning (vac), and most such mutants are also defective in vacuole protein sorting (vps) from the Golgi to the vacuole. Both the vps mutants and previously identified non-vps vac mutants display an altered vacuolar morphology. Here, we report a new method to monitor vacuole inheritance and the isolation of six new non-vps vac mutants. They define five complementation groups (VAC8-VAC12). Unlike mutants identified previously, three of the complementation groups exhibit normal vacuolar morphology. Zygote studies revealed that these vac mutants are also defective in intervacuole communication. Although at least four pathways of protein delivery to the vacuole are known, only the Vps pathway seems to significantly overlap with vacuole partitioning. Mutants defective in both vacuole partitioning and endocytosis or vacuole partitioning and autophagy were not observed. However, one of the new vac mutants was additionally defective in direct protein transport from the cytoplasm to the vacuole.
Wang
Y X
YX
Department of Biochemistry, University of Iowa, Iowa City 52242, USA.
Zhao
H
H
Harding
T M
TM
Gomes de Mesquita
D S
DS
Woldringh
C L
CL
Klionsky
D J
DJ
Munn
A L
AL
Weisman
L S
LS
D000626:Aminopeptidases / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics; D004705:Endocytosis / Q000235:genetics; D005434:Flow Cytometry / Q000379:methods; D005453:Fluorescence; D005456:Fluorescent Dyes; D005656:Fungal Proteins / Q000378:metabolism*; D005816:Genetic Complementation Test; D006056:Golgi Apparatus / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics; D009154:Mutation; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D011726:Pyridinium Compounds / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D025262:Vacuolar Proton-Translocating ATPases; D014617:Vacuoles / Q000145:classification / Q000235:genetics* / Q000502:physiology; D015003:Yeasts / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D015053:Zygote
C092350:FM 4-64; D005456:Fluorescent Dyes; D005656:Fungal Proteins; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D029701:Saccharomyces cerevisiae Proteins; D000626:Aminopeptidases; C019689:APE1 protein, S cerevisiae; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases