scholarly journals Sly1 protein bound to Golgi syntaxin Sed5p allows assembly and contributes to specificity of SNARE fusion complexes

2002 ◽  
Vol 157 (4) ◽  
pp. 645-655 ◽  
Author(s):  
Renwang Peng ◽  
Dieter Gallwitz
Keyword(s):  
Complex Formation ◽  
Snare Complex ◽  
Marked Contrast ◽  
Transport Vesicles ◽  
Target Membrane ◽  
First Time ◽  
Kinetics Of ◽  
Specific Membrane ◽  
Snare Complex Formation

Fusion of transport vesicles with their target organelles involves specific membrane proteins, SNAREs, which form tight complexes bridging the membranes to be fused. Evidence from yeast and mammals indicates that Sec1 family proteins act as regulators of membrane fusion by binding to the target membrane SNAREs. In experiments with purified proteins, we now made the observation that the ER to Golgi core SNARE fusion complex could be assembled on syntaxin Sed5p tightly bound to the Sec1-related Sly1p. Sly1p also bound to preassembled SNARE complexes in vitro and was found to be part of a vesicular/target membrane SNARE complex immunoprecipitated from yeast cell lysates. This is in marked contrast to the exocytic SNARE assembly in neuronal cells where high affinity binding of N-Sec1/Munc-18 to syntaxin 1A precluded core SNARE fusion complex formation. We also found that the kinetics of SNARE complex formation in vitro with either Sly1p-bound or free Sed5p was not significantly different. Importantly, several presumably nonphysiological SNARE complexes easily generated with Sed5p did not form when the syntaxin was first bound to Sly1p. This indicates for the first time that a Sec1 family member contributes to the specificity of SNARE complex assembly.

scholarly journals mTOR-mediated phosphorylation of VAMP8 and SCFD1 regulates autophagosome maturation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hong Huang ◽  
Qinqin Ouyang ◽  
Min Zhu ◽  
Haijia Yu ◽  
Kunrong Mei ◽  
...  
Keyword(s):  
Complex Formation ◽  
Lipid Droplet ◽  
Mouse Liver ◽  
Mammalian Target Of Rapamycin ◽  
Snare Complex ◽  
Target Of Rapamycin ◽  
Protein Receptor ◽  
Autophagosome Maturation ◽  
Snare Complex Formation

AbstractThe mammalian target of rapamycin (mTORC1) has been shown to regulate autophagy at different steps. However, how mTORC1 regulates the N-ethylmaleimide-sensitive protein receptor (SNARE) complex remains elusive. Here we show that mTORC1 inhibits formation of the SNARE complex (STX17-SNAP29-VAMP8) by phosphorylating VAMP8, thereby blocking autophagosome-lysosome fusion. A VAMP8 phosphorylation mimic mutant is unable to promote autophagosome-lysosome fusion in vitro. Furthermore, we identify SCFD1, a Sec1/Munc18-like protein, that localizes to the autolysosome and is required for SNARE complex formation and autophagosome-lysosome fusion. VAMP8 promotes SCFD1 recruitment to autolysosomes when dephosphorylated. Consistently, phosphorylated VAMP8 or SCFD1 depletion inhibits autophagosome-lysosome fusion, and expression of phosphomimic VAMP8 leads to increased lipid droplet accumulation when expressed in mouse liver. Thus, our study supports that mTORC1-mediated phosphorylation of VAMP8 blocks SCFD1 recruitment, thereby inhibiting STX17-SNAP29-VAMP8 complex formation and autophagosome-lysosome fusion.

scholarly journals rsly1 Binding to Syntaxin 5 Is Required for Endoplasmic Reticulum-to-Golgi Transport but Does Not Promote SNARE Motif Accessibility

2004 ◽  
Vol 15 (1) ◽  
pp. 162-175 ◽  
Author(s):  
Antionette L. Williams ◽  
Sebastian Ehm ◽  
Noëlle C. Jacobson ◽  
Dalu Xu ◽  
Jesse C. Hay
Keyword(s):  
Endoplasmic Reticulum ◽  
Complex Formation ◽  
Protein Function ◽  
Snare Complex ◽  
Golgi Transport ◽  
Snare Motif ◽  
Sm Protein ◽  
Snare Complex Formation

Although some of the principles of N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) function are well understood, remarkably little detail is known about sec1/munc18 (SM) protein function and its relationship to SNAREs. Popular models of SM protein function hold that these proteins promote or maintain an open and/or monomeric pool of syntaxin molecules available for SNARE complex formation. To address the functional relationship of the mammalian endoplasmic reticulum/Golgi SM protein rsly1 and its SNARE binding partner syntaxin 5, we produced a conformation-specific monoclonal antibody that binds only the available, but not the cis-SNARE–complexed nor intramolecularly closed form of syntaxin 5. Immunostaining experiments demonstrated that syntaxin 5 SNARE motif availability is nonuniformly distributed and focally regulated. In vitro endoplasmic reticulum-to-Golgi transport assays revealed that rsly1 was acutely required for transport, and that binding to syntaxin 5 was absolutely required for its function. Finally, manipulation of rsly1–syntaxin 5 interactions in vivo revealed that they had remarkably little impact on the pool of available syntaxin 5 SNARE motif. Our results argue that although rsly1 does not seem to regulate the availability of syntaxin 5, its function is intimately associated with syntaxin binding, perhaps promoting a later step in SNARE complex formation or function.

scholarly journals An intramolecular t-SNARE complex functions in vivo without the syntaxin NH2-terminal regulatory domain

2006 ◽  
Vol 172 (2) ◽  
pp. 295-307 ◽  
Author(s):  
Jeffrey S. Van Komen ◽  
Xiaoyang Bai ◽  
Brenton L. Scott ◽  
James A. McNew
Keyword(s):  
Plasma Membrane ◽  
Complex Formation ◽  
Secretory Pathway ◽  
Regulatory Element ◽  
Snare Complex ◽  
Regulatory Domain ◽  
Vesicle Membrane ◽  
Snare Complex Formation

Membrane fusion in the secretory pathway is mediated by SNAREs (located on the vesicle membrane [v-SNARE] and the target membrane [t-SNARE]). In all cases examined, t-SNARE function is provided as a three-helix bundle complex containing three ∼70–amino acid SNARE motifs. One SNARE motif is provided by a syntaxin family member (the t-SNARE heavy chain), and the other two helices are contributed by additional t-SNARE light chains. The syntaxin family is the most conformationally dynamic group of SNAREs and appears to be the major focus of SNARE regulation. An NH2-terminal region of plasma membrane syntaxins has been assigned as a negative regulatory element in vitro. This region is absolutely required for syntaxin function in vivo. We now show that the required function of the NH2-terminal regulatory domain (NRD) of the yeast plasma membrane syntaxin, Sso1p, can be circumvented when t-SNARE complex formation is made intramolecular. Our results suggest that the NRD is required for efficient t-SNARE complex formation and does not recruit necessary scaffolding factors.

scholarly journals Synaptotagmin Expands Membrane Fusion Pore by Facilitating SNARE-Complex Formation

2011 ◽  
Vol 100 (3) ◽  
pp. 185a
Author(s):  
Jiajie Diao ◽  
Janghyun Yoo ◽  
Han-Ki Lee ◽  
Yoosoo Yang ◽  
Dae-Hyuk Kweon ◽  
...  
Keyword(s):  
Complex Formation ◽  
Membrane Fusion ◽  
Snare Complex ◽  
Fusion Pore ◽  
Snare Complex Formation

scholarly journals IMMUNE RESPONSES IN VITRO

1971 ◽  
Vol 134 (2) ◽  
pp. 395-416 ◽  
Author(s):  
Carl W. Pierce ◽  
Barbara M. Johnson ◽  
Harriet E. Gershon ◽  
Richard Asofsky
Keyword(s):  
Culture Conditions ◽  
Antibody Concentration ◽  
Spleen Cells ◽  
Immunoglobulin Class ◽  
Cell Densities ◽  
Erythrocyte Antigen ◽  
First Time ◽  
Kinetics Of

We have demonstrated for the first time that mouse spleen cells stimulated in vitro with heterologous erythrocytes developed immunoglobulin class-specific γM, γ1, γ2a+2b, and γA plaque-forming cell (PFC) responses. A modification of the hemolytic plaque technique, the addition of goat anti-mouse µ-chain antibody to the assay preparation, specifically prevented development of all γM PFC and enabled accurate and reproducible enumeration of immunoglobulin class-specific PFC after treatment with appropriate monospecific anti-globulins and complement. Culture conditions, with regard to medium, atmosphere, agitation, and spleen cell densities, were similar to those previously shown to support only γM PFC responses. Evaluation of the kinetics of appearance of PFC showed that γM PFC reached maximum numbers on days 4–5; the magnitude of this response was 3–10 times greater than γ1 γ2a+2b, or γA PFC which reached maximum numbers on days 5–6. Optimal erythrocyte antigen dose for γM PFC responses was 107/culture, whereas a dose of 106 erythrocytes/culture consistently stimulated optimal γ1 γ2a+2b, or γA PFC responses. Investigations of the effects of anti-erythrocyte antibody on γM and γG PFC responses indicated that antibody suppressed these responses by neutralizing the effective antigenic stimulus at the macrophage-dependent phase of the response. At the same antibody concentration, γG PFC responses were more effectively suppressed than γM PFC responses. Further, γG responses could be almost completely suppressed by antibody as long as 48 hr after initiation of cultures, whereas γM PFC responses could only be completely suppressed during the first 24 hr. These results were discusssed in terms of the role of antigen in the stimulation γM and γG antibody.

scholarly journals Structural and Functional Analysis of the CAPS SNARE-Binding Domain Required for SNARE Complex Formation and Exocytosis

Cell Reports ◽  
2019 ◽  
Vol 26 (12) ◽  
pp. 3347-3359.e6 ◽  
Author(s):  
Hao Zhou ◽  
Ziqing Wei ◽  
Shen Wang ◽  
Deqiang Yao ◽  
Rongguang Zhang ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Complex Formation ◽  
Binding Domain ◽  
Snare Complex ◽  
Snare Complex Formation

scholarly journals Copper blocks V‐ATPase activity and SNARE complex formation to inhibit yeast vacuole fusion

Traffic ◽  
2019 ◽  
Vol 20 (11) ◽  
pp. 841-850 ◽  
Author(s):  
Gregory E. Miner ◽  
Katherine D. Sullivan ◽  
Chi Zhang ◽  
Logan R. Hurst ◽  
Matthew L. Starr ◽  
...  
Keyword(s):  
Complex Formation ◽  
Atpase Activity ◽  
Snare Complex ◽  
Yeast Vacuole ◽  
Vacuole Fusion ◽  
Snare Complex Formation

scholarly journals Dual inhibition of SNARE complex formation by tomosyn ensures controlled neurotransmitter release

2008 ◽  
Vol 183 (2) ◽  
pp. 323-337 ◽  
Author(s):  
Toshiaki Sakisaka ◽  
Yasunori Yamamoto ◽  
Sumiko Mochida ◽  
Michiko Nakamura ◽  
Kouki Nishikawa ◽  
...  
Keyword(s):  
Complex Formation ◽  
Neurotransmitter Release ◽  
Snare Complex ◽  
Protein Receptor ◽  
Repeat Domain ◽  
Dual Inhibition ◽  
Presynaptic Nerve Terminals ◽  
Synaptic Vesicle Fusion ◽  
Deficient Mice ◽  
Snare Complex Formation

Neurotransmitter release from presynaptic nerve terminals is regulated by soluble NSF attachment protein receptor (SNARE) complex–mediated synaptic vesicle fusion. Tomosyn inhibits SNARE complex formation and neurotransmitter release by sequestering syntaxin-1 through its C-terminal vesicle-associated membrane protein (VAMP)–like domain (VLD). However, in tomosyn-deficient mice, the SNARE complex formation is unexpectedly decreased. In this study, we demonstrate that the N-terminal WD-40 repeat domain of tomosyn catalyzes the oligomerization of the SNARE complex. Microinjection of the tomosyn N-terminal WD-40 repeat domain into neurons prevented stimulated acetylcholine release. Thus, tomosyn inhibits neurotransmitter release by catalyzing oligomerization of the SNARE complex through the N-terminal WD-40 repeat domain in addition to the inhibitory activity of the C-terminal VLD.

Regulation of SNARE complex formation by 8-nitro-cGMP

2010 ◽  
Vol 68 ◽  
pp. e116-e117
Author(s):  
Kouhei Kunieda ◽  
Tomoaki Ida ◽  
Tomohiro Sawa ◽  
Takaaki Akaike ◽  
Makoto Itakura ◽  
...  
Keyword(s):  
Complex Formation ◽  
Snare Complex ◽  
Snare Complex Formation
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