Regulation of SNARE complex assembly by an N-terminal domain of the t-SNARE Sso1p

The fusion of yeast vacuoles, like other organelles, requires a Rab-family guanosine triphosphatase (Ypt7p), a Rab effector and Sec1/Munc18 (SM) complex termed HOPS (homotypic fusion and vacuole protein sorting), and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). The central 0-layer of the four bundled vacuolar SNAREs requires the wild-type three glutaminyl (Q) and one arginyl (R) residues for optimal fusion. Alterations of this layer dramatically increase the Km value for SNAREs to assemble trans-SNARE complexes and to fuse. We now find that added purified HOPS complex strongly suppresses the fusion of vacuoles bearing 0-layer alterations, but it has little effect on the fusion of vacuoles with wild-type SNAREs. HOPS proofreads at two levels, inhibiting the formation of trans-SNARE complexes with altered 0-layers and suppressing the ability of these mismatched 0-layer trans-SNARE complexes to support membrane fusion. HOPS proofreading also extends to other parts of the SNARE complex, because it suppresses the fusion of trans-SNARE complexes formed without the N-terminal Phox homology domain of Vam7p (Qc). Unlike some other SM proteins, HOPS proofreading does not require the Vam3p (Qa) N-terminal domain. HOPS thus proofreads SNARE domain and N-terminal domain structures and regulates the fusion capacity of trans-SNARE complexes, only allowing full function for wild-type SNARE configurations. This is the most direct evidence to date that HOPS is directly involved in the fusion event.

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Hemophagocytic lymphohistiocytosis caused by dominant-negative mutations in STXBP2 that inhibit SNARE-mediated membrane fusion

Blood ◽

10.1182/blood-2014-11-610816 ◽

2015 ◽

Vol 125 (10) ◽

pp. 1566-1577 ◽

Cited By ~ 64

Author(s):

Waldo A. Spessott ◽

Maria L. Sanmillan ◽

Margaret E. McCormick ◽

Nishant Patel ◽

Joyce Villanueva ◽

...

Keyword(s):

Membrane Fusion ◽

Hemophagocytic Lymphohistiocytosis ◽

Dominant Negative ◽

Snare Complex ◽

Complex Assembly ◽

Mutant Proteins ◽

Key Points ◽

Lymphocyte Cytotoxicity ◽

Dominant Negative Mutations

Key Points Monoallelic STXBP2 mutations affecting codon 65 impair lymphocyte cytotoxicity and contribute to hemophagocytic lymphohistiocytosis. Munc18-2R65Q/W mutant proteins function in a dominant-negative manner to impair membrane fusion and arrest SNARE-complex assembly.

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Sec1p Binds to SNARE Complexes and Concentrates at Sites of Secretion

The Journal of Cell Biology ◽

10.1083/jcb.146.2.333 ◽

1999 ◽

Vol 146 (2) ◽

pp. 333-344 ◽

Cited By ~ 220

Author(s):

Chavela M. Carr ◽

Eric Grote ◽

Mary Munson ◽

Frederick M. Hughson ◽

Peter J. Novick

Keyword(s):

Fluorescent Protein ◽

Snare Complex ◽

The Other ◽

Complex Assembly ◽

Vesicle Docking ◽

Neuronal Protein ◽

The Core ◽

Target Membrane ◽

Green Fluorescent ◽

And Function

Proteins of the Sec1 family have been shown to interact with target-membrane t-SNAREs that are homologous to the neuronal protein syntaxin. We demonstrate that yeast Sec1p coprecipitates not only the syntaxin homologue Ssop, but also the other two exocytic SNAREs (Sec9p and Sncp) in amounts and in proportions characteristic of SNARE complexes in yeast lysates. The interaction between Sec1p and Ssop is limited by the abundance of SNARE complexes present in sec mutants that are defective in either SNARE complex assembly or disassembly. Furthermore, the localization of green fluorescent protein (GFP)-tagged Sec1p coincides with sites of vesicle docking and fusion where SNARE complexes are believed to assemble and function. The proposal that SNARE complexes act as receptors for Sec1p is supported by the mislocalization of GFP-Sec1p in a mutant defective for SNARE complex assembly and by the robust localization of GFP-Sec1p in a mutant that fails to disassemble SNARE complexes. The results presented here place yeast Sec1p at the core of the exocytic fusion machinery, bound to SNARE complexes and localized to sites of secretion.

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Inhibition of SNARE Complex Assembly Differentially Affects Kinetic Components of Exocytosis

Cell ◽

10.1016/s0092-8674(00)81669-4 ◽

1999 ◽

Vol 99 (7) ◽

pp. 713-722 ◽

Cited By ~ 203

Author(s):

Tao Xu ◽

Burkhard Rammner ◽

Martin Margittai ◽

Antonio R Artalejo ◽

Erwin Neher ◽

...

Keyword(s):

Snare Complex ◽

Complex Assembly

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Microsecond Dissection of Neurotransmitter Release: SNARE-Complex Assembly Dictates Speed and Ca2+ Sensitivity

Neuron ◽

10.1016/j.neuron.2014.04.020 ◽

2014 ◽

Vol 82 (5) ◽

pp. 1088-1100 ◽

Cited By ~ 36

Author(s):

Claudio Acuna ◽

Qingchen Guo ◽

Jacqueline Burré ◽

Manu Sharma ◽

Jianyuan Sun ◽

...

Keyword(s):

Neurotransmitter Release ◽

Snare Complex ◽

Complex Assembly

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Carboxyl-terminal Domain III of the δ′ Subunit of DNA Polymerase III Holoenzyme Binds DnaX and Supports Cooperative DnaX Complex Assembly

Journal of Biological Chemistry ◽

10.1074/jbc.m107936200 ◽

2001 ◽

Vol 276 (52) ◽

pp. 48709-48715 ◽

Cited By ~ 13

Author(s):

Min-Sun Song ◽

Charles S. McHenry

Keyword(s):

Dna Polymerase ◽

Dna Polymerase Iii ◽

Complex Assembly ◽

Terminal Domain ◽

Carboxyl Terminal Domain ◽

Polymerase Iii ◽

Carboxyl Terminal ◽

Domain Iii

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Ordering the Final Events in Yeast Exocytosis

The Journal of Cell Biology ◽

10.1083/jcb.151.2.439 ◽

2000 ◽

Vol 151 (2) ◽

pp. 439-452 ◽

Cited By ~ 117

Author(s):

Eric Grote ◽

Chavela M. Carr ◽

Peter J. Novick

Keyword(s):

Plasma Membrane ◽

Fusion Protein ◽

Late Stage ◽

Binding Protein ◽

Secretory Vesicle ◽

Snare Complex ◽

Wild Type ◽

Attachment Protein ◽

Complex Assembly ◽

Protein Receptor

In yeast, assembly of exocytic soluble N-ethylmaleimide–sensitive fusion protein (NSF) attachment protein receptor (SNARE) complexes between the secretory vesicle SNARE Sncp and the plasma membrane SNAREs Ssop and Sec9p occurs at a late stage of the exocytic reaction. Mutations that block either secretory vesicle delivery or tethering prevent SNARE complex assembly and the localization of Sec1p, a SNARE complex binding protein, to sites of secretion. By contrast, wild-type levels of SNARE complexes persist in the sec1-1 mutant after a secretory block is imposed, suggesting a role for Sec1p after SNARE complex assembly. In the sec18-1 mutant, cis-SNARE complexes containing surface-accessible Sncp accumulate in the plasma membrane. Thus, one function of Sec18p is to disassemble SNARE complexes on the postfusion membrane.

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A new role for RINT-1 in SNARE complex assembly at the trans-Golgi network in coordination with the COG complex

Molecular Biology of the Cell ◽

10.1091/mbc.e13-01-0014 ◽

2013 ◽

Vol 24 (18) ◽

pp. 2907-2917 ◽

Cited By ~ 12

Author(s):

Kohei Arasaki ◽

Daichi Takagi ◽

Akiko Furuno ◽

Miwa Sohda ◽

Yoshio Misumi ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Membrane Trafficking ◽

Retrograde Transport ◽

Snare Complex ◽

Initial Contact ◽

Complex Assembly ◽

Trans Golgi Network ◽

Cog Complex ◽

Protein Receptor ◽

Golgi Network

Docking and fusion of transport vesicles/carriers with the target membrane involve a tethering factor–mediated initial contact followed by soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE)–catalyzed membrane fusion. The multisubunit tethering CATCHR family complexes (Dsl1, COG, exocyst, and GARP complexes) share very low sequence homology among subunits despite likely evolving from a common ancestor and participate in fundamentally different membrane trafficking pathways. Yeast Tip20, as a subunit of the Dsl1 complex, has been implicated in retrograde transport from the Golgi apparatus to the endoplasmic reticulum. Our previous study showed that RINT-1, the mammalian counterpart of yeast Tip20, mediates the association of ZW10 (mammalian Dsl1) with endoplasmic reticulum–localized SNARE proteins. In the present study, we show that RINT-1 is also required for endosome-to–trans-Golgi network trafficking. RINT-1 uncomplexed with ZW10 interacts with the COG complex, another member of the CATCHR family complex, and regulates SNARE complex assembly at the trans-Golgi network. This additional role for RINT-1 may in part reflect adaptation to the demand for more diverse transport routes from endosomes to the trans-Golgi network in mammals compared with those in a unicellular organism, yeast. The present findings highlight a new role of RINT-1 in coordination with the COG complex.

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