The Yeast Endosomal t‐SNARE, Pep12p, Functions in the Absence of its Transmembrane Domain

Gerrard, Sonja R.; Mecklem, Alison B.; Stevens, Tom H.

doi:10.1034/j.1600-0854.2000.010108.x

Cited by 31 publications

(29 citation statements)

References 56 publications

(104 reference statements)

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“…Endosomal Qa-SNARE Pep12p can be largely substituted for vacuolar Qa-SNARE Vam3p in lipid mixing assays (Fig. 3, B-D), and this supports the in vivo observation that overexpression of PEP12 suppressed vacuole fragmentation in the vam3 deletion strain (40). Thus, Qc-SNAREs may be more important for mediating fusion specificity, rather than other SNARE subfamilies.…”

Section: Discussionsupporting

confidence: 69%

Distinct Contributions of Vacuolar Qabc- and R-SNARE Proteins to Membrane Fusion Specificity

Izawa

Onoue

Furukawa

et al. 2012

Journal of Biological Chemistry

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Background: Qabc-and R-SNARE proteins are key components for membrane fusion in eukaryotic organelles. Results: Reconstituted SNARE proteoliposomal study reveals distinct contributions of Qabc-and R-SNAREs to the specificity of membrane fusion. Conclusion: An assembly of proper Qabc-SNARE combinations is critical for mediating fusion specificity. Significance: This provides new insights for understanding how cells organize their complex membrane trafficking pathways.

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Section: Discussionsupporting

confidence: 69%

Distinct Contributions of Vacuolar Qabc- and R-SNARE Proteins to Membrane Fusion Specificity

Izawa

Onoue

Furukawa

et al. 2012

Journal of Biological Chemistry

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“…Also, vacuoles lacking Nyv1p can dock (62). However, these results do not preclude the action of other SNAREs in docking: Pep12p, a homolog of Vam3p, and Ykt6p, a homolog of Nyv1p, both can enter vacuolar SNARE complexes (36,63). Other studies of the involvement of SNAREs in docking have used intact organelles (32,64), which are likely to contain multiple sets of SNAREs that could also form ''noncanonical'' SNARE complexes (65) that mediate docking but not membrane fusion.…”

Section: Discussionmentioning

confidence: 93%

Minimal membrane docking requirements revealed by reconstitution of Rab GTPase-dependent membrane fusion from purified components

Stroupe

Hickey

Mima

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

106

143

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Rab GTPases and their effectors mediate docking, the initial contact of intracellular membranes preceding bilayer fusion. However, it has been unclear whether Rab proteins and effectors are sufficient for intermembrane interactions. We have recently reported reconstituted membrane fusion that requires yeast vacuolar SNAREs, lipids, and the homotypic fusion and vacuole protein sorting (HOPS)/class C Vps complex, an effector and guanine nucleotide exchange factor for the yeast vacuolar Rab GTPase Ypt7p. We now report reconstitution of lysis-free membrane fusion that requires purified GTP-bound Ypt7p, HOPS complex, vacuolar SNAREs, ATP hydrolysis, and the SNARE disassembly catalysts Sec17p and Sec18p. We use this reconstituted system to show that SNAREs and Sec17p/Sec18p, and Ypt7p and the HOPS complex, are required for stable intermembrane interactions and that the three vacuolar Q-SNAREs are sufficient for these interactions.biochemical reconstitution ͉ Rab effector

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“…A well-characterized component of the MVB of S. cerevisiae is the t-SNARE Pep12p, which interacts with another t-SNARE with a very similar sequence, Vam3p (58). In fact, overexpression of Pep12p can suppress the phenotype of ⌬Vam3p and vice versa (59,60). The genomes of N. crassa and other filamentous fungi encode only one protein with a similar sequence, which has led to an inconsistent naming of this gene.…”

Section: Discussionmentioning

confidence: 99%

Characterization of a Novel Prevacuolar Compartment in Neurospora crassa

et al. 2015

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Using confocal microscopy, we observed ring-like organelles, similar in size to nuclei, in the hyphal tip of the filamentous fungus Neurospora crassa. These organelles contained a subset of vacuolar proteins. We hypothesize that they are novel prevacuolar compartments (PVCs). We examined the locations of several vacuolar enzymes and of fluorescent compounds that target the vacuole. Vacuolar membrane proteins, such as the vacuolar ATPase (VMA-1) and the polyphosphate polymerase (VTC-4), were observed in the PVCs. A pigment produced by adenine auxotrophs, used to visualize vacuoles, also accumulated in PVCs. Soluble enzymes of the vacuolar lumen, alkaline phosphatase and carboxypeptidase Y, were not observed in PVCs. The fluorescent molecule Oregon Green 488 carboxylic acid diacetate, succinimidyl ester (carboxy-DFFDA) accumulated in vacuoles and in a subset of PVCs, suggesting maturation of PVCs from the tip to distal regions. Three of the nine Rab GTPases in N. crassa, RAB-2, RAB-4, and RAB-7, localized to the PVCs. RAB-2 and RAB-4, which have similar amino acid sequences, are present in filamentous fungi but not in yeasts, and no function has previously been reported for these Rab GTPases in fungi. PVCs are highly pleomorphic, producing tubular projections that subsequently become detached. Dynein and dynactin formed globular clusters enclosed inside the lumen of PVCs. The size, structure, dynamic behavior, and protein composition of the PVCs appear to be significantly different from those of the well-studied prevacuolar compartment of yeasts.T he vacuolar compartments in cells of fungi and plants have many of the same functions as the lysosomal compartments of animal cells (1-5). The defining characteristics of vacuoles and lysosomes are (i) the presence of a variety of hydrolytic enzymes such as proteases and phosphatases that help to degrade and recycle macromolecules and (ii) the maintenance of an acidic internal pH. An electrochemical gradient for protons is generated across vacuolar/lysosomal membranes by the vacuolar ATPase, a large complex enzyme (1, 6).We have been investigating the structure and function of the vacuolar compartments in filamentous fungi, using Neurospora crassa as our model organism. In fungi, vacuoles have multiple functions in addition to the degradation of macromolecules. They are involved in the regulation of arginine and ornithine metabolism, osmoregulation, and cytosolic ion and pH homeostasis. Fungal vacuoles contain high concentrations of basic amino acids, calcium, and polyphosphate (1, 4, 5).The vacuolar compartment in filamentous fungi has a complex structure and is highly dynamic (3,7,8). Many vacuoles have internal contents with a different refractive index than that of the cytosol, allowing them to be visualized with Nomarski optics. These vacuoles, prominent in older parts of the hypha, are spherical, ranging in size from Ͻ0.5 m to Ͼ10 m. Other vacuoles, prominent in the first hyphal segment, take the form of a dense network of interconnected tubules (9, 10). For N. cra...

show abstract

The Yeast Endosomal t‐SNARE, Pep12p, Functions in the Absence of its Transmembrane Domain

Cited by 31 publications

References 56 publications

Distinct Contributions of Vacuolar Qabc- and R-SNARE Proteins to Membrane Fusion Specificity

Distinct Contributions of Vacuolar Qabc- and R-SNARE Proteins to Membrane Fusion Specificity

Minimal membrane docking requirements revealed by reconstitution of Rab GTPase-dependent membrane fusion from purified components

Characterization of a Novel Prevacuolar Compartment in Neurospora crassa

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