rab3, a low molecular weight GTP-binding protein, is primarily expressed in brain, where it present soluble and membrane-bound forms. Membrane-bound rab3 brain exclusively localized on synaptic vesicles, the secretory organelles of synapse that store release neurotransmitters. also endocrine tissues such as adrenal medulla, found together with other vesicle proteins microvesicles distinct from chromaffin granules. The tight binding to membranes correlates hydrophobic modifications are...

Syntaxin 1 and synaptosome-associated protein of 25 kD (SNAP-25) are neuronal plasmalemma proteins that appear to be essential for exocytosis synaptic vesicles (SVs). Both form a complex with synaptobrevin, an intrinsic membrane SVs. This binding is thought responsible vesicle docking apparently precedes fusion. According the current concept, syntaxin SNAP-25 members larger families, collectively designated as target-SNAP receptors (t-SNAREs), whose specific localization subcellular...

Membrane traffic in eukaryotic cells requires that specific v-SNAREs on transport vesicles interact with t-SNAREs target membranes. We identified a novel Saccharomyces cerevisiae v-SNARE (Vti1p) encoded by the essential gene, VTI1. Vti1p interacts prevacuolar t-SNARE Pep12p to direct Golgi traffic. vti1-1 mutant missorted and secreted soluble vacuolar hydrolase carboxypeptidase Y (CPY) rapidly reversibly when were shifted restrictive temperature. However, overexpression of suppressed CPY...

Significance It was always a dream to control cells and living animals by light. Discovery of channelrhodopsin turned the into reality because this light-activated cation channel is able elicit action potentials with unprecedented spatial temporal resolution. To unravel underlying molecular mechanism, we have applied time-resolved IR spectroscopy, suggest how observed proton transfer protein conformational changes lead opening channel. Our results will not only contribute rational design...

Abstract Dendritic cells (DCs) present foreign antigen in major histocompatibility complex (MHC) class I molecules to cytotoxic T a process called cross-presentation. An important step this is the release of from lumen endosomes into cytosol, but mechanism still unclear. In study, we show that reactive oxygen species (ROS) produced by NADPH-oxidase NOX2 cause lipid peroxidation, membrane disrupting chain-reaction, which turn results leakage endosomes. Antigen and cross-presentation were...

Vacuole SNAREs, including the t-SNAREs Vam3p and Vam7p v-SNARE Nyv1p, are found in a multisubunit “cis” complex on isolated organelles. We now identify v-SNAREs Vti1p Ykt6p by mass spectrometry as additional components of immunoisolated vacuolar SNARE complex. Immunodepletion detergent extracts with anti-Vti1p removes all that is Vam3p, immunodepletion anti-Ykt6p complexed anti-Nyv1p other demonstrating they together same cis multi-SNARE After priming, which disassembles cis-SNARE complex,...

The interaction between v-SNAREs on transport vesicles and t-SNAREs target membranes is required for membrane traffic in eukaryotic cells. Here we identify Vti1p as the first v-SNARE protein found to be biosynthetic into yeast vacuole, equivalent of mammalian lysosome. Certain vti1-tsyeast mutants are defective alkaline phosphatase from Golgi vacuole targeting aminopeptidase I cytosol vacuole. VTI1 interacts genetically with vacuolar t-SNARE VAM3, which both Nyv1p forms a SNARE complex Vam3p...

Rab3 proteins are small GTP-binding of the Ras superfamily. Four highly homologous termed Rab3A, Rab3B, Rab3C, and Rab3D have been described. Rab3A has previously shown to be a constituent synaptic vesicles in neurons that undergoes membrane dissociation-association cycles during vesicle recycling. Here we report Rab3C copurifies with isolation vesicles. Organelles immunoisolated monoclonal antibodies directed against led coenrichment demonstrating both colocalized on same organelle. In...

Membrane traffic in eukaryotic cells relies on recognition between v-SNAREs transport vesicles and t-SNAREs target membranes. Here we report the identification of AtVTI1a AtVTI1b, twoArabidopsis homologues yeast v-SNARE Vti1p, which is required for multiple steps yeast. AtVTI1b share 60% amino acid identity with one another are 32 30% identical to protein, respectively. By suppressing defects found specific strains vti1temperature-sensitive mutants, show that can substitute Vti1p...

SNARE proteins are required for fusion of transport vesicles with target membranes. Previously, we found that the yeast Q-SNARE Vti1p is involved in to cis-Golgi, prevacuole/late endosome, and vacuole. Here identified a previously uncharacterized gene, VTS1, R-SNAREYKT6 both as multicopy low copy suppressors growth vacuolar defect vti1–2 cells. Ykt6p was known function retrograde traffic cis-Golgi homotypic fusion. We VTI1 andYKT6 also interacted prevacuole vacuole, indicating these...

SNARE proteins participate in recognition and fusion of membranes. A complex consisting vti1b, syntaxin 8, 7, endobrevin/VAMP-8 which is required for late endosomes vitro has been identified recently. Here, we generated mice deficient vti1b to study the function this protein vivo. vti1b-deficient had reduced amounts 8 due degradation protein, while 7 endobrevin did not change. These data indicate that specifically stability a single partner. were viable fertile. Most indistinguishable from...

A novel membrane protein from rat brain synaptic vesicles with an apparent 29,000 Mr (p29) was characterized. Using monospecific polyclonal antibodies, the distribution of p29 studied in a variety tissues by light and electron microscopy immunoblot analysis. Within nervous system, present virtually all nerve terminals. It selectively associated small perinuclear region corresponding to area Golgi complex. P29 not detected any other subcellular organelles including large dense-core vesicles....

EpsinR is a clathrin-coated vesicle (CCV)-associated protein that binds to vti1b, suggesting it may be vti1b-selective adaptor. Depletion of epsinR undetectable levels in HeLa cells using siRNA causes vti1b redistribute from the perinuclear region cell periphery, but vti1a also redistributes epsinR-depleted cells, and both vti isoforms AP-1-depleted cells. As more direct assay for function, we isolated CCVs control siRNA-treated then looked differences cargo content. In clathrin-depleted...

The SNAREs Vti1a/1b are implicated in regulated secretion, but their role relative to canonical exocytic remains elusive. Here, we show that synaptic vesicle and dense-core (DCV) secretion is indeed severely impaired Vti1a/b-deficient neurons. levels of proteins mediate were reduced, down 50% for the SNARE SNAP25. delivery SNAP25 DCV-cargo into axons was decreased these molecules accumulated Golgi. These defects rescued by either Vti1a or Vti1b expression. Distended Golgi cisternae clear...

SNARE proteins on transport vesicles and target membranes have important roles in vesicle targeting fusion. Therefore, localization activity of SNAREs to be tightly controlled. Regulatory bind N-terminal domains some SNAREs. vti1b is a mammalian that functions late endosomal To investigate the role N terminus we performed yeast two-hybrid screen. The interacted specifically with epsin homology (ENTH) domain enthoprotin/CLINT/epsinR. interaction was confirmed using vitro binding assays. This...

Specific soluble N -ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (SNARE) proteins are required for different membrane transport steps. The SNARE Vti1a has been colocalized with Golgi markers and Vti1b the trans -Golgi network or endosomal in fibroblast cell lines. Here we study distribution of brain. was found synaptic vesicles but not enriched this organelle. A brain-specific splice variant identified that had an insertion seven amino acid residues next to putative...

Fusion between membranes is mediated by specific SNARE complexes. Here we report that fibroblasts survive the absence of trans-Golgi network/early endosomal vti1a and late vti1b with intact organelle morphology minor trafficking defects. Because are only members their subclass yeast homolog Vti1p essential for cell survival, these data suggest more distantly related SNAREs acquired ability to function in traffic during evolution. However, resulted perinatal lethality. Major axon tracts were...

The exocytosis of cytotoxic proteins stored in lytic granules activated CTL is a key event during killing target cells. Membrane fusion events that are mediated by soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) crucial, as demonstrated patients with familial hemophagocytic lymphohistocytosis type 4 who have mutations the SNARE syntaxin-11 result an impaired degranulation We found increased mRNA expression genes Vti1b and Vamp8 Ag-specific activation from...

The mechanism of the cytotoxic function cisplatin and related anticancer drugs is based on their binding to nucleobases DNA. development new classes requires establishing other modes. Therefore, we performed a rational design for complexes that target two neighboring phosphates DNA backbone by molecular recognition resulting in family dinuclear 2,7-disubstituted 1,8-naphthalenediol. This rigid preorganizes metal ions at distance 6–7 Å. Additionally, bulky chelating pendant arms 2,7-position...