scholarly journals Endosomal and Phagosomal SNAREs

2018 ◽  
Vol 98 (3) ◽  
pp. 1465-1492 ◽  
Author(s):  
Ilse Dingjan ◽  
Peter T. A. Linders ◽  
Danielle R. J. Verboogen ◽  
Natalia H. Revelo ◽  
Martin ter Beest ◽  
...  
Keyword(s):  
Intracellular Transport ◽  
Snare Proteins ◽  
Intracellular Pathogens ◽  
Snare Protein ◽  
Attachment Protein ◽  
System A ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Organelle Communication ◽  
Factor Attachment Protein Receptor

The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein family is of vital importance for organelle communication. The complexing of cognate SNARE members present in both the donor and target organellar membranes drives the membrane fusion required for intracellular transport. In the endocytic route, SNARE proteins mediate trafficking between endosomes and phagosomes with other endosomes, lysosomes, the Golgi apparatus, the plasma membrane, and the endoplasmic reticulum. The goal of this review is to provide an overview of the SNAREs involved in endosomal and phagosomal trafficking. Of the 38 SNAREs present in humans, 30 have been identified at endosomes and/or phagosomes. Many of these SNAREs are targeted by viruses and intracellular pathogens, which thereby reroute intracellular transport for gaining access to nutrients, preventing their degradation, and avoiding their detection by the immune system. A fascinating picture is emerging of a complex transport network with multiple SNAREs being involved in consecutive trafficking routes.

scholarly journals Localization, Dynamics, and Protein Interactions Reveal Distinct Roles for ER and Golgi SNAREs

1998 ◽  
Vol 141 (7) ◽  
pp. 1489-1502 ◽  
Author(s):  
Jesse C. Hay ◽  
Judith Klumperman ◽  
Viola Oorschot ◽  
Martin Steegmaier ◽  
Christin S. Kuo ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Protein Interactions ◽  
The Other ◽  
Snare Proteins ◽  
Attachment Protein ◽  
Golgi Transport ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Coated Membranes ◽  
Factor Attachment Protein Receptor

ER-to-Golgi transport, and perhaps intraGolgi transport involves a set of interacting soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) proteins including syntaxin 5, GOS-28, membrin, rsec22b, and rbet1. By immunoelectron microscopy we find that rsec22b and rbet1 are enriched in COPII-coated vesicles that bud from the ER and presumably fuse with nearby vesicular tubular clusters (VTCs). However, all of the SNAREs were found on both COPII- and COPI-coated membranes, indicating that similar SNARE machinery directs both vesicle pathways. rsec22b and rbet1 do not appear beyond the first Golgi cisterna, whereas syntaxin 5 and membrin penetrate deeply into the Golgi stacks. Temperature shifts reveal that membrin, rsec22b, rbet1, and syntaxin 5 are present together on membranes that rapidly recycle between peripheral and Golgi-centric locations. GOS-28, on the other hand, maintains a fixed localization in the Golgi. By immunoprecipitation analysis, syntaxin 5 exists in at least two major subcomplexes: one containing syntaxin 5 (34-kD isoform) and GOS-28, and another containing syntaxin 5 (41- and 34-kD isoforms), membrin, rsec22b, and rbet1. Both subcomplexes appear to involve direct interactions of each SNARE with syntaxin 5. Our results indicate a central role for complexes among rbet1, rsec22b, membrin, and syntaxin 5 (34 and 41 kD) at two membrane fusion interfaces: the fusion of ER-derived vesicles with VTCs, and the assembly of VTCs to form cis-Golgi elements. The 34-kD syntaxin 5 isoform, membrin, and GOS-28 may function in intraGolgi transport.

scholarly journals Prefused lysosomes cluster on autophagosomes regulated by VAMP8

2021 ◽  
Vol 12 (10) ◽  
Author(s):  
Qixin Chen ◽  
Mingang Hao ◽  
Lei Wang ◽  
Linsen Li ◽  
Yang Chen ◽  
...  
Keyword(s):  
Potential Role ◽  
Autophagic Flux ◽  
Snare Protein ◽  
Attachment Protein ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Fusion Probability ◽  
Autophagosome Maturation ◽  
Factor Attachment Protein Receptor

AbstractLysosome–autophagosome fusion is critical to autophagosome maturation. Although several proteins that regulate this fusion process have been identified, the prefusion architecture and its regulation remain unclear. Herein, we show that upon stimulation, multiple lysosomes form clusters around individual autophagosomes, setting the stage for membrane fusion. The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein on lysosomes—vesicle-associated membrane protein 8 (VAMP8)—plays an important role in forming this prefusion state of lysosomal clusters. To study the potential role of phosphorylation on spontaneous fusion, we investigated the effect of phosphorylation of C-terminal residues of VAMP8. Using a phosphorylation mimic, we observed a decrease of fusion in an ensemble lipid mixing assay and an increase of unfused lysosomes associated with autophagosomes. These results suggest that phosphorylation not only reduces spontaneous fusion for minimizing autophagic flux under normal conditions, but also preassembles multiple lysosomes to increase the fusion probability for resuming autophagy upon stimulation. VAMP8 phosphorylation may thus play an important role in chemotherapy drug resistance by influencing autophagosome maturation.

scholarly journals Autophagosomal YKT6 is required for fusion with lysosomes independently of syntaxin 17

2018 ◽  
Vol 217 (8) ◽  
pp. 2633-2645 ◽  
Author(s):  
Takahide Matsui ◽  
Peidu Jiang ◽  
Saori Nakano ◽  
Yuriko Sakamaki ◽  
Hayashi Yamamoto ◽  
...  
Keyword(s):  
Hela Cells ◽  
Snare Complex ◽  
Snare Protein ◽  
Wild Type ◽  
Attachment Protein ◽  
Additional Mechanism ◽  
Protein Receptor ◽  
Evolutionarily Conserved ◽  
Sensitive Factor ◽  
Factor Attachment Protein Receptor

Macroautophagy is an evolutionarily conserved catabolic mechanism that delivers intracellular constituents to lysosomes using autophagosomes. To achieve degradation, lysosomes must fuse with closed autophagosomes. We previously reported that the soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) protein syntaxin (STX) 17 translocates to autophagosomes to mediate fusion with lysosomes. In this study, we report an additional mechanism. We found that autophagosome–lysosome fusion is retained to some extent even in STX17 knockout (KO) HeLa cells. By screening other human SNAREs, we identified YKT6 as a novel autophagosomal SNARE protein. Depletion of YKT6 inhibited autophagosome–lysosome fusion partially in wild-type and completely in STX17 KO cells, suggesting that YKT6 and STX17 are independently required for fusion. YKT6 formed a SNARE complex with SNAP29 and lysosomal STX7, both of which are required for autophagosomal fusion. Recruitment of YKT6 to autophagosomes depends on its N-terminal longin domain but not on the C-terminal palmitoylation and farnesylation that are essential for its Golgi localization. These findings suggest that two independent SNARE complexes mediate autophagosome–lysosome fusion.

Distinct Initial SNARE Configurations Underlying the Diversity of Exocytosis

2012 ◽  
Vol 92 (4) ◽  
pp. 1915-1964 ◽  
Author(s):  
Haruo Kasai ◽  
Noriko Takahashi ◽  
Hiroshi Tokumaru
Keyword(s):  
Membrane Trafficking ◽  
Synaptic Vesicles ◽  
Cell Types ◽  
Snare Proteins ◽  
Attachment Protein ◽  
Protein Receptor ◽  
Large Dense Core Vesicles ◽  
Sensitive Factor ◽  
The Common ◽  
Kinetics Of

The dynamics of exocytosis are diverse and have been optimized for the functions of synapses and a wide variety of cell types. For example, the kinetics of exocytosis varies by more than five orders of magnitude between ultrafast exocytosis in synaptic vesicles and slow exocytosis in large dense-core vesicles. However, in all cases, exocytosis is mediated by the same fundamental mechanism, i.e., the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. It is often assumed that vesicles need to be docked at the plasma membrane and SNARE proteins must be preassembled before exocytosis is triggered. However, this model cannot account for the dynamics of exocytosis recently reported in synapses and other cells. For example, vesicles undergo exocytosis without prestimulus docking during tonic exocytosis of synaptic vesicles in the active zone. In addition, epithelial and hematopoietic cells utilize cAMP and kinases to trigger slow exocytosis of nondocked vesicles. In this review, we summarize the manner in which the diversity of exocytosis reflects the initial configurations of SNARE assembly, including trans-SNARE, binary-SNARE, unitary-SNARE, and cis-SNARE configurations. The initial SNARE configurations depend on the particular SNARE subtype (syntaxin, SNAP25, or VAMP), priming proteins (Munc18, Munc13, CAPS, complexin, or snapin), triggering proteins (synaptotagmins, Doc2, and various protein kinases), and the submembraneous cytomatrix, and they are the key to determining the kinetics of subsequent exocytosis. These distinct initial configurations will help us clarify the common SNARE assembly processes underlying exocytosis and membrane trafficking in eukaryotic cells.

scholarly journals Syntaxin 16 is a master recruitment factor for cytokinesis

2013 ◽  
Vol 24 (23) ◽  
pp. 3663-3674 ◽  
Author(s):  
Hélia Neto ◽  
Alexandra Kaupisch ◽  
Louise L. Collins ◽  
Gwyn W. Gould
Keyword(s):  
Membrane Vesicles ◽  
Attachment Protein ◽  
Recycling Endosome ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Late Telophase ◽  
Intracellular Organelles ◽  
Factor Attachment Protein Receptor

Recently it was shown that both recycling endosome and endosomal sorting complex required for transport (ESCRT) components are required for cytokinesis, in which they are believed to act in a sequential manner to bring about secondary ingression and abscission, respectively. However, it is not clear how either of these complexes is targeted to the midbody and whether their delivery is coordinated. The trafficking of membrane vesicles between different intracellular organelles involves the formation of soluble N-ethylmalei­mide–sensitive factor attachment protein receptor (SNARE) complexes. Although membrane traffic is known to play an important role in cytokinesis, the contribution and identity of intracellular SNAREs to cytokinesis remain unclear. Here we demonstrate that syntaxin 16 is a key regulator of cytokinesis, as it is required for recruitment of both recycling endosome–associated Exocyst and ESCRT machinery during late telophase, and therefore that these two distinct facets of cytokinesis are inextricably linked.

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