scholarly journals Competitive organelle-specific adaptors recruit Vps13 to membrane contact sites

2018 ◽  
Vol 217 (10) ◽  
pp. 3593-3607 ◽  
Author(s):  
Björn D.M. Bean ◽  
Samantha K. Dziurdzik ◽  
Kathleen L. Kolehmainen ◽  
Claire M.S. Fowler ◽  
Waldan K. Kwong ◽  
...  
Keyword(s):  
Repeat Region ◽  
Contact Site ◽  
Sorting Nexin ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Prospore Membrane ◽  
Membrane Contacts ◽  
Membrane Contact ◽  
Vacuolar Membranes ◽  
Mitochondrial Membrane Protein

The regulated expansion of membrane contact sites, which mediate the nonvesicular exchange of lipids between organelles, requires the recruitment of additional contact site proteins. Yeast Vps13 dynamically localizes to membrane contacts that connect the ER, mitochondria, endosomes, and vacuoles and is recruited to the prospore membrane in meiosis, but its targeting mechanism is unclear. In this study, we identify the sorting nexin Ypt35 as a novel adaptor that recruits Vps13 to endosomal and vacuolar membranes. We characterize an interaction motif in the Ypt35 N terminus and identify related motifs in the prospore membrane adaptor Spo71 and the mitochondrial membrane protein Mcp1. We find that Mcp1 is a mitochondrial adaptor for Vps13, and the Vps13–Mcp1 interaction, but not Ypt35, is required when ER-mitochondria contacts are lost. All three adaptors compete for binding to a conserved six-repeat region of Vps13 implicated in human disease. Our results support a competition-based model for regulating Vps13 localization at cellular membranes.

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.

scholarly journals Uniform nomenclature for the mitochondrial contact site and cristae organizing system

2014 ◽  
Vol 204 (7) ◽  
pp. 1083-1086 ◽  
Author(s):  
Nikolaus Pfanner ◽  
Martin van der Laan ◽  
Paolo Amati ◽  
Roderick A. Capaldi ◽  
Amy A. Caudy ◽  
...  
Keyword(s):  
Large Protein ◽  
Contact Site ◽  
Inner Membrane ◽  
Future Studies ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Mitochondrial Inner Membrane ◽  
Large Protein Complex ◽  
Membrane Contact ◽  
Uniform Nomenclature

The mitochondrial inner membrane contains a large protein complex that functions in inner membrane organization and formation of membrane contact sites. The complex was variably named the mitochondrial contact site complex, mitochondrial inner membrane organizing system, mitochondrial organizing structure, or Mitofilin/Fcj1 complex. To facilitate future studies, we propose to unify the nomenclature and term the complex “mitochondrial contact site and cristae organizing system” and its subunits Mic10 to Mic60.

scholarly journals Peroxisomal Membrane Contact Sites in Yeasts

2021 ◽  
Vol 9 ◽  
Author(s):  
Amit S. Joshi
Keyword(s):  
Lipid Droplets ◽  
Peroxisome Biogenesis ◽  
Functional Importance ◽  
Peroxisomal Membrane ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Recent Developments ◽  
Membrane Contacts ◽  
Membrane Bound ◽  
Membrane Contact

Peroxisomes are ubiquitous, single membrane-bound organelles that play a crucial role in lipid metabolism and human health. While peroxisome number is maintained by the division of existing peroxisomes, nascent peroxisomes can be generated from the endoplasmic reticulum (ER) membrane in yeasts. During formation and proliferation, peroxisomes maintain membrane contacts with the ER. In addition to the ER, contacts between peroxisomes and other organelles such as lipid droplets, mitochondria, vacuole, and plasma membrane have been reported. These membrane contact sites (MCS) are dynamic and important for cellular function. This review focuses on the recent developments in peroxisome biogenesis and the functional importance of peroxisomal MCS in yeasts.

scholarly journals The Drosophila photoreceptor as a model system for studying signalling at membrane contact sites

2016 ◽  
Vol 44 (2) ◽  
pp. 447-451 ◽  
Author(s):  
Shweta Yadav ◽  
Shamshad Cockcroft ◽  
Padinjat Raghu
Keyword(s):  
Membrane Composition ◽  
Contact Site ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Physiological Processes ◽  
Specific Proteins ◽  
Intracellular Organelles ◽  
Membrane Contact ◽  
Cellular Compartments

Several recent studies have demonstrated the existence of membrane contact sites (MCS) between intracellular organelles in eukaryotic cells. Recent exciting studies have also demonstrated the existence of biomolecular interactions at these contact sites in mediating changes in the membrane composition of the cellular compartments. However, the role of such contact sites in regulating organelle function and physiological processes remains less clear. In this review we discuss the existence of a contact site between the plasma membrane (PM) and the endoplasmic reticulum (ER) in Drosophila photoreceptors. Further, we discuss the role of specific proteins present at this location in regulating phospholipid turnover and its impact in regulating a physiological process, namely phototransduction.

scholarly journals Spermiogenesis in the acoel Symsagittifera roscoffensis: nucleus-plasma membrane contact sites and microtubules

2019 ◽  
Author(s):  
Matthew J. Hayes ◽  
Anne-C. Zakrzewski ◽  
Tim P. Levine ◽  
Maximilian J. Telford
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Intertidal Zone ◽  
Mature Spermatozoon ◽  
Sandy Beaches ◽  
Contact Site ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Specific Contact ◽  
Membrane Contact

AbstractSymsagittifera roscoffensis is a small marine worm found in the intertidal zone of sandy beaches around the European shores of the Atlantic. S. roscoffensis is a member of the Acoelomorpha, a group of flatworms formerly classified with the Platyhelminthes, but now recognised as Xenacoelomorpha, a separate phylum of disputed affinity. We have used electron microscopy to examine the process of spermiogenesis (the final stage of spermatogenesis) in S. roscoffensis, by which spermatids form highly elongated spermatozoa. Their nuclei are long and thread-like, running most of the cell’s length and during the process a pair of flagella are fully incorporated into the cell body. Two previously undescribed inter-organelle contact sites form at different stages of spermiogenesis. Strikingly, there is an extensive nucleus-plasma membrane contact site. Golgi-derived granules containing electron-dense filaments line up along the spermatid plasma membrane, undergo a conformational change, and donate material that forms a peri-nuclear layer that cements this contact site. We also show in earlier stage spermatids that the same granules are associated with microtubules, presumably for traffic along the elongating cell. We identify a second spermiogenesis-specific contact site where sheaths engulfing each internalising flagellum contact the nuclear envelope. Finally, detailed studies of the spermatozoon axonemes show that the central keel has varying numbers of microtubules along the length of the cell, and is likely to be a centriole derivative.Summary sentenceDuring spermiogenesis in the acoel flatworm Symsagittifera roscoffensis, two previously unidentified contact sites contribute to the structure of the mature spermatozoon and the axonemal structures show direct continuity between doublet and dense core microtubules.

Nucleus–vacuole junctions in yeast: anatomy of a membrane contact site

2006 ◽  
Vol 34 (3) ◽  
pp. 340-342 ◽  
Author(s):  
E. Kvam ◽  
D.S. Goldfarb
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Model System ◽  
Specific Interactions ◽  
Contact Site ◽  
Vacuole Membrane ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Unique Model ◽  
Membrane Contact ◽  
Autophagic Process

NV junctions (nucleus–vacuole junctions) in Saccharomyces cerevisiae are MCSs (membrane contact sites) formed through specific interactions between Vac8p on the vacuole membrane and Nvj1p in the outer nuclear membrane, which is continuous with the perinuclear ER (endoplasmic reticulum). NV junctions mediate a unique autophagic process that degrades portions of the yeast nucleus through a process called ‘piecemeal microautophagy of the nucleus’ (PMN). Our studies suggest that the lipid composition of NV junctions plays an important role in the biogenesis of PMN structures. NV junctions represent a unique model system for studying the biology of ER MCSs, as well as the molecular mechanism of selective microautophagy.

scholarly journals SNAP iN, SNAP oUT—SNAREs at ER-PM Contact Sites

Contact ◽  
2020 ◽  
Vol 3 ◽  
pp. 251525642097958
Author(s):  
Neha Pratap Singh ◽  
Christian Vannier ◽  
Thierry Galli
Keyword(s):  
Protein Complexes ◽  
Short Review ◽  
Lipid Transfer ◽  
Contact Site ◽  
Lipid Transfer Proteins ◽  
Homologous Proteins ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact ◽  
Organelle Communication

Inter-organelle communication is essential for the exchange of cellular content in eukaryotes, particularly at membrane contact sites between the endoplasmic reticulum (ER) and the plasma membrane (PM). Accomplishing this critical task requires close positioning of the involved membranes via tether proteins and associated complexes. One such complex involves the SNAREs Sec22b and Syntaxin 1. Discovered to be interacting at the ER-PM membrane contact site (MCS), Sec22b-Stx1 forms a unique non-fusogenic bridge tethering the two membranes. Contrarily, SNAP25 was shown to be absent from the Sec22b-Stx1 complexes. Two recent studies focused on this interplay of SNARES and Lipid transfer proteins at MCSs. The Longin domain of Sec22b appeared to be the reason behind SNAP25’s exclusion from Sec22b-Stx1 assembly, and inclusion of E-Syts. It was also shown that yeast Sec9p and mammalian SNAP25 regulate ER-PM contact sites via their interaction with LTP OSBP-homologous proteins (ORP/OSH). In this following short review, we will take a closer look at the protein complexes involving SNAREs at MCSs and potential regulation by the Longin domain of Sec22b.

scholarly journals Roles for ER:endosome membrane contact sites in ligand-stimulated intraluminal vesicle formation

2018 ◽  
Vol 46 (5) ◽  
pp. 1055-1062 ◽  
Author(s):  
Louise H. Wong ◽  
Emily R. Eden ◽  
Clare E. Futter
Keyword(s):  
Membrane Proteins ◽  
Mammalian Cells ◽  
Tyrosine Phosphatase ◽  
Endosomal Sorting ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contacts ◽  
Epidermal Growth ◽  
Membrane Contact ◽  
Multivesicular Endosomes

Multivesicular endosomes/bodies (MVBs) sort membrane proteins between recycling and degradative pathways. Segregation of membrane proteins onto intraluminal vesicles (ILVs) of MVBs removes them from the recycling pathway and facilitates their degradation following fusion of MVBs with lysosomes. Sorting of many cargos onto ILVs depends on the ESCRT (Endosomal Sorting Complex Required for Transport) machinery, although ESCRT-independent mechanisms also exist. In mammalian cells, efficient sorting of ligand-stimulated epidermal growth factor receptors onto ILVs also depends on the tyrosine phosphatase, PTP1B, an ER-localised enzyme that interacts with endosomal targets at membrane contacts between MVBs and the ER. This review focuses on the potential roles played by ER:MVB membrane contact sites in regulating ESCRT-dependent ILV formation.

scholarly journals Nucleus–Plasma Membrane Contact Sites Are Formed During Spermiogenesis in the Acoel Symsagittifera roscoffensis

Contact ◽  
2020 ◽  
Vol 3 ◽  
pp. 251525642092635
Author(s):  
Matthew J. Hayes ◽  
Anne-C. Zakrzewski ◽  
Timothy P. Levine ◽  
Maximilian J. Telford
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Final Stage ◽  
Intertidal Zone ◽  
Sandy Beaches ◽  
Contact Site ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Specific Contact ◽  
Membrane Contact

Symsagittifera roscoffensis is a small marine worm found in the intertidal zone of sandy beaches around the European shores of the Atlantic. S. roscoffensis is a member of the Acoelomorpha, a group of flatworms formerly classified with the Platyhelminthes, but now recognized as Xenacoelomorpha, a separate phylum of disputed affinity. We have used electron microscopy to examine the process of spermiogenesis (the final stage of spermatogenesis) in S. roscoffensis, by which spermatids form highly elongated spermatozoa. Their nuclei are long and thread-like, running most of the cell’s length, and during the process, a pair of flagella are fully incorporated into the cell body. Two previously undescribed interorganelle contact sites form at different stages of spermiogenesis. Strikingly, there is an extensive nucleus–plasma membrane contact site. Golgi-derived granules containing electron-dense filaments line up along the spermatid plasma membrane, undergo a conformational change, and donate material that forms a perinuclear layer that cements this contact site. We also show in spermatids at an earlier stage that the same granules are associated with microtubules, presumably for traffic along the elongating cell. We identify a second spermiogenesis-specific contact site where sheaths engulfing each internalizing flagellum contact the nuclear envelope.

scholarly journals An expanded palette of improved SPLICS reporters detects multiple organelle contacts in vitro and in vivo

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Francesca Vallese ◽  
Cristina Catoni ◽  
Domenico Cieri ◽  
Lucia Barazzuol ◽  
Omar Ramirez ◽  
...  
Keyword(s):  
Contact Site ◽  
Cell Homeostasis ◽  
Distance Range ◽  
Physiological Conditions ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact ◽  
Living Organisms

AbstractMembrane contact sites between virtually any known organelle have been documented and, in the last decades, their study received momentum due to their importance for fundamental activities of the cell and for the subtle comprehension of many human diseases. The lack of tools to finely image inter-organelle proximity hindered our understanding on how these subcellular communication hubs mediate and regulate cell homeostasis. We develop an improved and expanded palette of split-GFP-based contact site sensors (SPLICS) for the detection of single and multiple organelle contact sites within a scalable distance range. We demonstrate their flexibility under physiological conditions and in living organisms.

Sign in / Sign up

Export Citation Format

Share Document