scholarly journals An MBoC Favorite: Morphological classification of the yeast vacuolar protein-sorting mutants: evidence for a prevacuolar compartment in class E vps mutants

2012 ◽  
Vol 23 (14) ◽  
pp. 2622-2622
Author(s):  
Rosine Haguenauer-Tsapis
Keyword(s):  
Protein Sorting ◽  
Morphological Classification ◽  
Vacuolar Protein Sorting ◽  
Prevacuolar Compartment ◽  
Vacuolar Protein ◽  
Class E

scholarly journals Morphological classification of the yeast vacuolar protein sorting mutants: evidence for a prevacuolar compartment in class E vps mutants.

1992 ◽  
Vol 3 (12) ◽  
pp. 1389-1402 ◽  
Author(s):  
C K Raymond ◽  
I Howald-Stevenson ◽  
C A Vater ◽  
T H Stevens
Keyword(s):  
Protein Sorting ◽  
Carboxypeptidase Y ◽  
Vacuolar Protein Sorting ◽  
Complementation Groups ◽  
Prevacuolar Compartment ◽  
Golgi Protein ◽  
Mother Cells ◽  
Vacuolar Protein ◽  
Morphological Phenotype

The collection of vacuolar protein sorting mutants (vps mutants) in Saccharomyces cerevisiae comprises of 41 complementation groups. The vacuoles in these mutant strains were examined using immunofluorescence microscopy. Most of the vps mutants were found to possess vacuolar morphologies that differed significantly from wild-type vacuoles. Furthermore, mutants representing independent vps complementation groups were found to share aberrant morphological features. Six distinct classes of vacuolar morphology were observed. Mutants from eight vps complementation groups were defective both for vacuolar segregation from mother cells into developing buds and for acidification of the vacuole. Another group of mutants, represented by 13 complementation groups, accumulated a novel organelle distinct from the vacuole that contained a late-Golgi protein, active vacuolar H(+)-ATPase complex, and soluble vacuolar hydrolases. We suggest that this organelle may represent an exaggerated endosome-like compartment. None of the vps mutants appeared to mislocalize significant amounts of the vacuolar membrane protein alkaline phosphatase. Quantitative immunoprecipitations of the soluble vacuolar hydrolase carboxypeptidase Y (CPY) were performed to determine the extent of the sorting defect in each vps mutant. A good correlation between morphological phenotype and the extent of the CPY sorting defect was observed.

scholarly journals The Doa4 Deubiquitinating Enzyme Is Functionally Linked to the Vacuolar Protein-sorting and Endocytic Pathways

2000 ◽  
Vol 11 (10) ◽  
pp. 3365-3380 ◽  
Author(s):  
Alexander Y. Amerik ◽  
Jonathan Nowak ◽  
Sowmya Swaminathan ◽  
Mark Hochstrasser
Keyword(s):  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Protein Sorting ◽  
Late Endosome ◽  
Deubiquitinating Enzyme ◽  
Vacuolar Protein Sorting ◽  
Prevacuolar Compartment ◽  
Green Fluorescent ◽  
Vacuolar Protein ◽  
Class E

The Saccharomyces cerevisiae DOA4 gene encodes a deubiquitinating enzyme that is required for rapid degradation of ubiquitin–proteasome pathway substrates. Both genetic and biochemical data suggest that Doa4 acts in this pathway by facilitating ubiquitin recycling from ubiquitinated intermediates targeted to the proteasome. Here we describe the isolation of 12 spontaneous extragenic suppressors of the doa4-1 mutation; these involve seven different genes, six of which were cloned. Surprisingly, all of the clonedDID (Doa4-independent degradation) genes encode components of the vacuolar protein-sorting (Vps) pathway. In particular, all are class E Vps factors, which function in the maturation of a late endosome/prevacuolar compartment into multivesicular bodies that then fuse with the vacuole. Four of the six Did proteins are structurally related, suggesting an overlap in function. In wild-type and several vps strains, Doa4–green fluorescent protein displays a cytoplasmic/nuclear distribution. However, in cells lacking the Vps4/Did6 ATPase, a large fraction of Doa4–green fluorescent protein, like several other Vps factors, concentrates at the late endosome–like class E compartment adjacent to the vacuole. These results suggest an unanticipated connection between protein deubiquitination and endomembrane protein trafficking in which Doa4 acts at the late endosome/prevacuolar compartment to recover ubiquitin from ubiquitinated membrane proteins en route to the vacuole.

scholarly journals HECT ubiquitin ligases link viral and cellular PPXY motifs to the vacuolar protein-sorting pathway

2004 ◽  
Vol 168 (1) ◽  
pp. 89-101 ◽  
Author(s):  
Juan Martin-Serrano ◽  
Scott W. Eastman ◽  
Wayne Chung ◽  
Paul D. Bieniasz
Keyword(s):  
Ubiquitin Ligase ◽  
Protein Sorting ◽  
Ubiquitin Ligases ◽  
Dominant Negative ◽  
Specific Class ◽  
Vacuolar Protein Sorting ◽  
Viral Budding ◽  
Virion Release ◽  
Vacuolar Protein ◽  
Class E

Many enveloped viruses exploit the class E vacuolar protein-sorting (VPS) pathway to bud from cells, and use peptide motifs to recruit specific class E VPS factors. Homologous to E6AP COOH terminus (HECT) ubiquitin ligases have been implicated as cofactors for PPXY motif–dependent budding, but precisely which members of this family are responsible, and how they access the VPS pathway is unclear. Here, we show that PPXY-dependent viral budding is unusually sensitive to inhibitory fragments derived from specific HECT ubiquitin ligases, namely WWP1 and WWP2. We also show that WWP1, WWP2, or Itch ubiquitin ligase recruitment promotes PPXY-dependent virion release, and that this function requires that the HECT ubiquitin ligase domain be catalytically active. Finally, we show that several mammalian HECT ubiquitin ligases, including WWP1, WWP2, and Itch are recruited to class E compartments induced by dominant negative forms of the class E VPS ATPase, VPS4. These data indicate that specific HECT ubiquitin ligases can link PPXY motifs to the VPS pathway to induce viral budding.

scholarly journals Multilamellar endosome-like compartment accumulates in the yeast vps28 vacuolar protein sorting mutant.

1996 ◽  
Vol 7 (6) ◽  
pp. 985-999 ◽  
Author(s):  
S E Rieder ◽  
L M Banta ◽  
K Köhrer ◽  
J M McCaffery ◽  
S D Emr
Keyword(s):  
Protein Sorting ◽  
Retrograde Transport ◽  
Carboxypeptidase Y ◽  
Coat Proteins ◽  
Electron Microscopic ◽  
Yeast Saccharomyces Cerevisiae ◽  
Intense Staining ◽  
Vacuolar Protein Sorting ◽  
Vacuolar Protein ◽  
Class E

In the yeast Saccharomyces cerevisiae, vacuolar proteins such as carboxypeptidase Y transit from the Golgi to the lysosome-like vacuole via an endosome-like intermediate compartment. The vacuolar protein sorting (vps) mutant vps28, a member of the "class E" vps mutants, accumulates vacuolar, endocytic, and late Golgi markers in an aberrant endosome-like class E compartment. Sequence analysis of VPS28 revealed an open reading frame predicted to encode a hydrophilic protein of 242 amino acids. Consistent with this, polyclonal antiserum raised against Vps28p recognized a cytoplasmic protein of 28 kDa. Disruption of VPS28 resulted in moderate defects in both biosynthetic traffic and endocytic traffic destined for the vacuole. The transport of soluble vacuolar hydrolases to the vacuole was impaired in vps28 null mutant cells (approximately 40-50% carboxypeptidase Y missorted). Internalization of the endocytic marker FM 4-64, a vital lipophilic dye, resulted in intense staining of a small intracellular compartment adjacent to an enlarged vacuole in delta vps28 cells. Furthermore, the vacuolar H+-ATPase accumulated in the perivacuolar class E compartment in delta vps28 cells, as did a-factor receptor Ste3p that was internalized from the plasma membrane. Electron microscopic analysis revealed the presence of a novel compartment consisting of stacks of curved membrane cisternae. Immunolocalization studies demonstrated that the vacuolar H+-ATPase is associated with this cupped cisternal structure, indicating that it corresponds to the class E compartment observed by fluorescence microscopy. Our data indicate that kinetic defects in both anterograde and retrograde transport out of the prevacuolar compartment in vps28 mutants result in the accumulation of protein and membrane in an exaggerated multilamellar endosomal compartment. We propose that Vps28p, as well as other class E Vps proteins, may facilitate (possibly as coat proteins) the formation of transport intermediates required for efficient transport out of the prevacuolar endosome.

scholarly journals VPS21Controls Entry of Endocytosed and Biosynthetic Proteins into the Yeast Prevacuolar Compartment

2000 ◽  
Vol 11 (2) ◽  
pp. 613-626 ◽  
Author(s):  
Sonja R. Gerrard ◽  
Nia J. Bryant ◽  
Tom H. Stevens
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Fusion ◽  
Protein Sorting ◽  
Vacuolar Protein Sorting ◽  
Endosomal Compartment ◽  
Early Endosomes ◽  
Strong Homology ◽  
Rab Family ◽  
Prevacuolar Compartment ◽  
Vacuolar Protein

Mutations in the VPS (vacuolar protein sorting) genes of Saccharomyces cerevisiae have been used to define the trafficking steps that soluble vacuolar hydrolases take en route from the late Golgi to the vacuole. The class DVPS genes include VPS21,PEP12, and VPS45, which appear to encode components of a membrane fusion complex involved in Golgi-to-endosome transport. Vps21p is a member of the Rab family of small Ras-like GTPases and shows strong homology to the mammalian Rab5 protein, which is involved in endocytosis and the homotypic fusion of early endosomes. Although Rab5 and Vps21p appear homologous at the sequence level, it has not been clear if the functions of these two Rabs are similar. We find that Vps21p is an endosomal protein that is involved in the delivery of vacuolar and endocytosed proteins to the vacuole. Vacuolar and endocytosed proteins accumulate in distinct transport intermediates in cells that lack Vps21p function. Therefore, it appears that Vps21p is involved in two trafficking steps into the prevacuolar/late endosomal compartment.

scholarly journals An Interorganellar Bidding War: Vps13 Localization by Competitive Organelle-Specific Adaptors

Contact ◽  
2018 ◽  
Vol 1 ◽  
pp. 251525641881462
Author(s):  
Samantha K. Dziurdzik ◽  
Björn D.M. Bean ◽  
Elizabeth Conibear
Keyword(s):  
Endoplasmic Reticulum ◽  
Recent Work ◽  
Protein Sorting ◽  
Repeat Region ◽  
Vacuolar Protein Sorting ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Prospore Membrane ◽  
Membrane Contact ◽  
Vacuolar Protein

Membrane contact sites are regulated through the controlled recruitment of constituent proteins. Yeast vacuolar protein sorting 13 (Vps13) dynamically localizes to membrane contact sites at endosomes, vacuoles, mitochondria, and the endoplasmic reticulum under different cellular conditions and is recruited to the prospore membrane during meiosis. Prior to our recent work, the mechanism for localization at contact sites was largely unknown. We identified Ypt35 as a novel Vps13 adaptor for endosomes and the nucleus-vacuole junction. Furthermore, we discovered a conserved recruitment motif in Ypt35 and found related motifs in the prospore membrane and mitochondrial adaptors, Spo71 and Mcp1, respectively. All three adaptors compete for binding to a six-repeat region of Vps13, suggesting adaptor competition regulates Vps13 localization. Here, we summarize and discuss the implications of our work, highlighting key outstanding questions.

Nystatin Sensitive and Vacuolar Protein Sorting Defective (vps) Mutants of Saccharomyces cerevisiae: Their Isolation and Characterization

2001 ◽  
Vol 4 (3) ◽  
pp. 259-262
Author(s):  
M. Shah Alam Bhuiyan ◽  
Yuji Ito . ◽  
Naotaka Tanaka . ◽  
Golam Sadik . ◽  
Kiyotaka Fujita . ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Sorting ◽  
Vacuolar Protein Sorting ◽  
Isolation And Characterization ◽  
Vacuolar Protein
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