scholarly journals SNARE zippering

2016 ◽  
Vol 36 (3) ◽  
Author(s):  
Xiaochu Lou ◽  
Yeon-Kyun Shin
Keyword(s):  
Recent Progress ◽  
Snare Complex ◽  
Intracellular Membrane ◽  
Attachment Protein ◽  
Receptor Proteins ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Associated Proteins ◽  
Intracellular Membrane Fusion ◽  
Factor Attachment Protein Receptor

SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins are a highly conserved set of membrane-associated proteins that mediate intracellular membrane fusion. Cognate SNAREs from two separate membranes zipper to facilitate membrane apposition and fusion. Though the stable post-fusion conformation of SNARE complex has been extensively studied with biochemical and biophysical means, the pathway of SNARE zippering has been elusive. In this review, we describe some recent progress in understanding the pathway of SNARE zippering. We particularly focus on the half-zippered intermediate, which is most likely to serve as the main point of regulation by the auxiliary factors.

scholarly journals Complexin suppresses spontaneous exocytosis by capturing the membrane-proximal regions of VAMP2 and SNAP25

2019 ◽  
Author(s):  
J. Malsam ◽  
S. Bärfuss ◽  
T. Trimbuch ◽  
F. Zarebidaki ◽  
A.F.-P. Sonnen ◽  
...  
Keyword(s):  
Snare Complex ◽  
Intracellular Membrane ◽  
Attachment Protein ◽  
Neuronal Protein ◽  
Synaptic Release ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Living Neurons ◽  
Multiple Domains ◽  
Intracellular Membrane Fusion

SummaryThe neuronal protein complexin contains multiple domains that exert both clamping and facilitatory functions to tune spontaneous and action potential triggered synaptic release. We address the clamping mechanism and show that the accessory helix of complexin arrests the assembly of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex that forms the core machinery of intracellular membrane fusion. In a reconstituted fusion assay, site- and stage-specific photo-cross-linking reveals that prior to fusion the complexin accessory helix laterally binds the membrane-proximal C-terminal ends of SNAP25 and VAMP2. Corresponding complexin interface mutants selectively increase spontaneous release of neurotransmitter in living neurons, implying that the accessory helix suppresses final zippering/assembly of the SNARE four-helix bundle by restraining VAMP2 and SNAP25.

scholarly journals Complexin splits the membrane-proximal region of a single SNAREpin

2016 ◽  
Vol 473 (14) ◽  
pp. 2219-2224 ◽  
Author(s):  
Linxiang Yin ◽  
Jaewook Kim ◽  
Yeon-Kyun Shin
Keyword(s):  
Neurotransmitter Release ◽  
Proximal Part ◽  
Proximal Region ◽  
Snare Complex ◽  
Spontaneous Release ◽  
Attachment Protein ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Membrane Proximal Region ◽  
Factor Attachment Protein Receptor

Tight regulation of neurotransmitter release by Ca2+ is critical in neurons, which requires suppression of spontaneous release. In the present study, we find that the complexin (Cpx) protein binds to the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex to split the membrane-proximal part, whereby it inhibits spontaneous release.

scholarly journals Characterization of VAMP isoforms in 3T3-L1 adipocytes: implications for GLUT4 trafficking

2015 ◽  
Vol 26 (3) ◽  
pp. 530-536 ◽  
Author(s):  
Jessica B. A. Sadler ◽  
Nia J. Bryant ◽  
Gwyn W. Gould
Keyword(s):  
Plasma Membrane ◽  
Snare Complex ◽  
Cell Type ◽  
Attachment Protein ◽  
Systematic Analysis ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Factor Attachment Protein Receptor

The fusion of GLUT4-containing vesicles with the plasma membrane of adipocytes is a key facet of insulin action. This process is mediated by the formation of functional soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) complexes between the plasma membrane t-SNARE complex and the vesicle v-SNARE or VAMP. The t-SNARE complex consists of Syntaxin4 and SNAP23, and whereas many studies identify VAMP2 as the v-SNARE, others suggest that either VAMP3 or VAMP8 may also fulfil this role. Here we characterized the levels of expression, distribution, and association of all the VAMPs expressed in 3T3-L1 adipocytes to provide the first systematic analysis of all members of this protein family for any cell type. Despite our finding that all VAMP isoforms form SDS-resistant SNARE complexes with Syntaxin4/SNAP23 in vitro, a combination of levels of expression (which vary by >30-fold), subcellular distribution, and coimmunoprecipitation analyses lead us to propose that VAMP2 is the major v-SNARE involved in GLUT4 trafficking to the surface of 3T3-L1 adipocytes.

scholarly journals Identification of Functionally Interacting SNAREs by Using Complementary Substitutions in the Conserved `0' Layer

2005 ◽  
Vol 16 (5) ◽  
pp. 2263-2274 ◽  
Author(s):  
Carmen T. Graf ◽  
Dietmar Riedel ◽  
Hans Dieter Schmitt ◽  
Reinhard Jahn
Keyword(s):  
Snare Complex ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Central Layer ◽  
Attachment Protein ◽  
Growth Defects ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Factor Attachment Protein Receptor

Soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) complexes form bundles of four parallel α-helices. The central `0' layer of interacting amino acid side chains is highly conserved and contains one arginine and three glutamines, leading to the classification of SNAREs into R, Qa, Qb, and Qc-SNAREs. Replacing one of the glutamines with arginine in the yeast exocytotic SNARE complex is either lethal or causes a conditional growth defect that is compensated by replacing the R-SNARE arginine with glutamine. Using the yeast SNARE complex mediating traffic from the endoplasmic reticulum to the Golgi apparatus, we now show that functionally interacting SNAREs can be mapped by systematically exchanging glutamines and arginines in the `0' layer. The Q→ R replacement in the Qb-SNARE Bos1p has the strongest effect and can be alleviated by an Q→ R replacement in the R-SNARE Sec22p. Four Q residues in the central layer caused growth defects above 30°C that were rescued by Q→ R substitutions in the Qa and Qc SNAREs Sed5p and Bet1p, respectively. The sec22(Q)/sed5(R) mutant is temperature sensitive and is rescued by a compensating R→ Q replacement in the R-SNARE Ykt6p. This rescue is attributed to the involvement of Sed5p and Ykt6p in a different SNARE complex that functions in intra-Golgi trafficking.

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.

scholarly journals VAMP3 and VAMP8 regulate the development and functionality of parasitophorous vacuoles housing Leishmania amazonensis

2020 ◽  
Author(s):  
Olivier Séguin ◽  
Linh Thuy Mai ◽  
Sidney W. Whiteheart ◽  
Simona Stäger ◽  
Albert Descoteaux
Keyword(s):  
Host Cell ◽  
Leishmania Amazonensis ◽  
Phagocytic Cells ◽  
Attachment Protein ◽  
Receptor Proteins ◽  
Cross Presentation ◽  
Data Support ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Factor Attachment Protein Receptor

ABSTRACTTo colonize mammalian phagocytic cells, the parasite Leishmania remodels phagosomes into parasitophorous vacuoles that can be either tight-fitting individual or communal. The molecular and cellular bases underlying the biogenesis and functionality of these two types of vacuoles are poorly understood. In this study, we investigated the contribution of host cell Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor proteins in the expansion and functionality of communal vacuoles as well as on the replication of the parasite. The differential recruitment patterns of Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor to communal vacuoles harboring L. amazonensis and to individual vacuoles housing L. major led us to further investigate the contribution of VAMP3 and VAMP8 in the interaction of Leishmania with its host cell. We show that whereas VAMP8 contributes to optimal expansion of communal vacuoles, VAMP3 negatively regulates L. amazonensis replication, vacuole size, as well as antigen cross-presentation. In contrast, neither proteins has an impact on the fate of L. major. Collectively, our data support a role for both VAMP3 and VAMP8 in the development and functionality of L. amazonensis-harboring communal parasitophorous vacuoles.

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