A5005679273- Cellular transport and secretion
- Lipid Membrane Structure and Behavior
- Calcium signaling and nucleotide metabolism
- Retinal Development and Disorders
- Autophagy in Disease and Therapy
- Endoplasmic Reticulum Stress and Disease
- RNA and protein synthesis mechanisms
- Plant-Microbe Interactions and Immunity
- Fungal and yeast genetics research
- Plant Disease Resistance and Genetics
- Mitochondrial Function and Pathology
- ATP Synthase and ATPases Research
- Erythrocyte Function and Pathophysiology
- Plant Gene Expression Analysis
- Lysosomal Storage Disorders Research
- Glycosylation and Glycoproteins Research
- Plant Reproductive Biology
- Photosynthetic Processes and Mechanisms
- Legume Nitrogen Fixing Symbiosis
Osnabrück University
2011-2025
Max Planck Society
2005
Max Planck Institute for Terrestrial Microbiology
2004-2005
Within the endomembrane system of eukaryotic cells, multisubunit tethering complexes together with their corresponding Rab-GTPases coordinate vesicle and fusion. Here, we present evidence that two homologous hexameric complexes, endosomal CORVET (Class C core vacuole/endosome transport) vacuolar HOPS (homotypic vacuole fusion protein sorting) complex, have similar subunit topologies. Both contain Rab-binding proteins at one end, Sec1/Munc18-like Vps33 opposite side, suggesting a model on...
Endosomes and lysosomes harbor Rab5 Rab7 on their surface as key proteins involved in identity, biogenesis, fusion. Rab activation requires a guanine nucleotide exchange factor (GEF), which is Mon1-Ccz1 for Rab7. During endosome maturation, replaced by Rab7, though the underlying mechanism remains poorly understood. Here, we identify molecular determinants conversion vivo vitro, reconstitute with yeast metazoan proteins. We show (i) that an effector of Rab5, (ii) membrane-bound to directly...
Activation of the small GTPase Rab7 by its cognate guanine nucleotide exchange factor Mon1-Ccz1 (MC1) is a key step in maturation endosomes and autophagosomes. This process tightly regulated subject to precise spatiotemporal control MC1 localization, but mechanisms that underly localization have not been fully elucidated. We here identify characterize an amphipathic helix Ccz1, which required for function Mon-Ccz1 autophagy, endosomal maturation. Furthermore, our data show interaction Ccz1...
Organelles of the endomembrane system contain Rab GTPases as identity markers. Their localization is determined by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). It remains largely unclear how these regulators are specifically targeted to organelles their activity regulated. Here, we focus on GAP Gyp7, which acts Rab7-like Ypt7 protein in yeast, surprisingly observe exclusively puncta proximal vacuole. Mistargeting Gyp7 vacuole strongly affects morphology,...
Fusion at the lysosome (or yeast vacuole) requires conserved hexameric HOPS tethering complex. binds to vacuolar Rab7-like GTPase Ypt7 via its subunits Vps41 and Vps39 supports fusion by promoting SNARE assembly. In contrast sister complex CORVET, Ypt7-interacting domain of in is connected core a long, extended α-solenoid domain. Here, we show that this solenoid acts as molecular ruler position Ypt7-interaction part relative support function. Mutant complexes with shortened or still tether...
Retrograde vesicular transport from the Golgi to ER requires Dsl1 tethering complex, which consists of three subunits Dsl1, Dsl3, and Tip20. It forms a stable complex with SNAREs Ufe1, Use1, Sec20 mediate fusion COPI vesicles endoplasmic reticulum. Here, we analyze molecular interactions between five (Ufe1, Sec20, Sec22, Ykt6) in vitro vivo. Of two R-SNAREs, Sec22 is preferred over Ykt6 Dsl-SNARE complex. The NSF homolog Sec18 can displace but not suggesting regulatory function for Ykt6. In...
Organelles of the endolysosomal system undergo multiple fission and fusion events to combine sorting selected proteins vacuole with endosomal recycling. This requires a consecutive remodeling organelle surface in course maturation. Here we dissect machinery on endosomes during process endocytosis. We traced GFP-tagged relative exogenously added fluorescently labeled α-factor its way from plasma membrane vacuole. Our data reveal that ESCRT has similar temporal localization endosomes, whereas...
Article25 August 2020Open Access AP-3 vesicle uncoating occurs after HOPS-dependent vacuole tethering Jannis Schoppe Department of Biology/Chemistry, Biochemistry Section, University Osnabrück, Germany Search for more papers by this author Muriel Mari Biomedical Sciences Cells and Systems, Medical Center Groningen, The Netherlands Erdal Yavavli Kathrin Auffarth Margarita Cabrera Departament de Ciències Experimentals i la Salut, Universitat Pompeu Farba, Barcelona, Spain Stefan Walter...
The Ustilago maydis mrb1 gene specifies a mitochondrial matrix protein with significant similarity to p32 family proteins known from human and many other eukaryotic species. Compatible mutant strains were able mate form dikaryotic hyphae; however, proliferation within infected tissue the ability induce tumor development of maize (Zea mays) plants drastically impaired. Surprisingly, manifestation phenotype selectively depended on a2 mating type locus. locus contains, in addition pheromone...
The dually lipidated SNARE Ykt6 is found on intracellular membranes and in the cytosol. In this study, we show that localizes to Golgi as well endosomal vacuolar vivo. ability of cycle between cytosol depends intramolecular interaction N-terminal longin C-terminal domains not either domain alone. A mutant deficient accumulates and--in contrast wild-type protein--does get released from vacuoles. Our data also indicate a substrate DHHC (Asp-His-His-Cys) acyltransferase network. Overexpression...
The smut fungus Ustilago maydis establishes a biotrophic relationship with its host plant maize to progress through sexual development. Here, we report the identification and characterization of Cys(2)His(2)-type zinc finger protein Mzr1 that functions as transcriptional activator during colonization. Expression U. mig2 cluster genes is tightly linked this phase. Upon conditional overexpression, confers induction subset vegetative growth requires same promoter elements confer inducible...
The Ustilago maydis mig2 cluster comprises five highly homologous genes that display a pronounced plant-specific expression profile. A 350-bp mig2-5 promoter fragment contained all elements sufficient to confer differential activity. Mutational analysis of this region, fused the green fluorescent protein reporter gene, allowed dissecting core required for high-level activity from conferring inducible in planta. In particular, presence several 5′-CCA-3′ motifs within short stretch was...
Endosomal and vacuole fusion depends on the two homologous tethering complexes CORVET HOPS. HOPS binds activated Rab GTPase Ypt7 via distinct subunits, Vps39 Vps41. To understand participation possible polarity of Vps41 during tethering, we used an in vivo approach. For this, established ligand-induced relocalization to plasma membrane, using Mon1-Ccz1 GEF complex that activates endosomes. We then employed slight overexpression compare mobility HOPS-specific subunits this process. Our data...
The hexameric HOPS (homotypic fusion and protein sorting) complex is a conserved tethering at the lysosome-like vacuole, where it mediates promotes all events involving this organelle. Vps39 subunit of also engages in membrane contact site between vacuole mitochondria, called vCLAMP. Additionally, four subunits are part endosomal CORVET complex. Here, we analyzed partition different complexes by tracing their localization function. We find that has specific role vCLAMP formation beyond...
Abstract Activation of the small GTPase Rab7 by its cognate guanine nucleotide exchange factor (GEF) Mon1-Ccz1 (MC1) is a key step in maturation endosomes and autophagosomes. This process tightly regulated subject to precise spatiotemporal control MC1 localization. We here identify characterize an amphipathic helix Ccz1, which required for function Mon-Ccz1 autophagy, but not endosomal maturation. Furthermore, our data show that interaction Ccz1 with lipid packing defects, binding Mon1 basic...