William Wickner
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View article: Functional assembly of the Qc-SNARE with Sec18 and Sec17 on membranes
Functional assembly of the Qc-SNARE with Sec18 and Sec17 on membranes Open
Yeast vacuolar fusion is driven by Sec17, Sec18, SNAREs of four families (R [Nyv1], Qa [Vam3], Qb [Vti1], Qc [Vam7]) and HOPS, a catalyst of SNARE assembly. Qc, the only vacuolar SNARE that is not membrane-anchored, has a unique path of as…
View article: Functional Assembly of the Qc-SNARE with Sec18 and Sec17 on Membranes
Functional Assembly of the Qc-SNARE with Sec18 and Sec17 on Membranes Open
Yeast vacuolar fusion is driven by Sec17, Sec18, SNAREs (R, Qa, Qb, Qc) and HOPS, a catalyst of SNARE assembly. Qc, the only vacuolar SNARE that is not membrane-anchored, has a unique path of assembly with other fusion catalysts. Qc is the…
View article: Membrane fusion reactions limited by defective SNARE zippering or stiff lipid fatty acyl composition have distinct requirements for Sec17, Sec18, and adenine nucleotide
Membrane fusion reactions limited by defective SNARE zippering or stiff lipid fatty acyl composition have distinct requirements for Sec17, Sec18, and adenine nucleotide Open
Intracellular membrane fusion is catalyzed by SNAREs, Rab GTPases, SM proteins, tethers, Sec18/NSF and Sec17/SNAP. Membrane fusion has been reconstituted with purified vacuolar proteins and lipids to address 3 salient questions: whether AT…
View article: After their membrane assembly, Sec18 (NSF) and Sec17 (SNAP) promote membrane fusion
After their membrane assembly, Sec18 (NSF) and Sec17 (SNAP) promote membrane fusion Open
The energy that drives membrane fusion can come from either complete SNARE zippering, from Sec17 and Sec18, or both. Sec17 and Sec18 initially form a complex which binds membranes. Sec17, Sec18, and the apolarity of a loop on the N-domain …
View article: SNARE disassembly requires Sec18/NSF side-loading
SNARE disassembly requires Sec18/NSF side-loading Open
SNARE proteins drive membrane fusion at different cell compartments as their core domains zipper into a parallel four-helix bundle. After fusion, these bundles are disassembled by the AAA+ protein Sec18/NSF and its adaptor Sec17/α-SNAP to …
View article: Sec18 binds the tethering/SM complex HOPS to engage the Qc-SNARE for membrane fusion
Sec18 binds the tethering/SM complex HOPS to engage the Qc-SNARE for membrane fusion Open
Membrane fusion is regulated by Rab GTPases, their tethering effectors such as HOPS, SNARE proteins on each fusion partner, SM proteins to catalyze SNARE assembly, Sec17 (SNAP), and Sec18 (NSF). Though concentrated HOPS can support fusion …
View article: PI3P regulates multiple stages of membrane fusion
PI3P regulates multiple stages of membrane fusion Open
Using reconstituted fusion with all purified proteins and defined lipids, four targets for PI3P regulation are reported: recruitment of the Qc-SNARE, trans-SNARE assembly between membranes, protection of SNARE complexes from the chaperones…
View article: Sec18 supports membrane fusion by promoting Sec17 membrane association
Sec18 supports membrane fusion by promoting Sec17 membrane association Open
Sec18, bound at a distance from membranes, lowers the Sec17 needed for fusion. To do this, Sec18 complexes with several Sec17 molecules, allowing Sec17 to bind membranes through its N-terminal apolar loop. Membrane-bound Sec17 engages SNAR…
View article: Fusion with wild-type SNARE domains is controlled by juxtamembrane domains, transmembrane anchors, and Sec17
Fusion with wild-type SNARE domains is controlled by juxtamembrane domains, transmembrane anchors, and Sec17 Open
Fusion is widely believed to be driven only by zippering of membrane-anchored SNARE domains. With wild-type SNARE domains, it is now shown that fusion also depends on each SNARE having its correct juxtamembrane domain, on the multiplicity …
View article: Fusion of tethered membranes can be driven by Sec18/NSF and Sec17/αSNAP without HOPS
Fusion of tethered membranes can be driven by Sec18/NSF and Sec17/αSNAP without HOPS Open
Yeast vacuolar membrane fusion has been reconstituted with R, Qa, Qb, and Qc-family SNAREs, Sec17/αSNAP, Sec18/NSF, and the hexameric HOPS complex. HOPS tethers membranes and catalyzes SNARE assembly into RQaQbQc trans -complexes which zip…
View article: Author response: Fusion of tethered membranes can be driven by Sec18/NSF and Sec17/αSNAP without HOPS
Author response: Fusion of tethered membranes can be driven by Sec18/NSF and Sec17/αSNAP without HOPS Open
Article Figures and data Abstract Editor's evaluation Introduction Results Discussion Materials and methods Data availability References Decision letter Author response Article and author information Metrics Abstract Yeast vacuolar membran…
View article: Phosphatidylinositol and phosphatidylinositol-3-phosphate activate HOPS to catalyze SNARE assembly, allowing small headgroup lipids to support the terminal steps of membrane fusion
Phosphatidylinositol and phosphatidylinositol-3-phosphate activate HOPS to catalyze SNARE assembly, allowing small headgroup lipids to support the terminal steps of membrane fusion Open
Vacuole membranes contain several lipid species. Membrane fusion occurs very poorly with just phosphatidylcholine. We now report that PI, PI3P, and Erg first activate HOPS to catalyze assembly of trans-SNARE complexes, and then PE, PS, PA,…
View article: Membrane Fusion can be Driven by Sec18/NSF, Sec17/αSNAP, and <i>trans</i> -SNARE complex without HOPS
Membrane Fusion can be Driven by Sec18/NSF, Sec17/αSNAP, and <i>trans</i> -SNARE complex without HOPS Open
Yeast vacuolar membrane fusion has been reconstituted with R, Qa, Qb, and Qc-family SNAREs, Sec17/αSNAP, Sec18/NSF, and the hexameric HOPS complex. HOPS tethers membranes and catalyzes SNARE assembly into RQaQbQc trans -complexes which zip…
View article: Sec17/Sec18 can support membrane fusion without help from completion of SNARE zippering
Sec17/Sec18 can support membrane fusion without help from completion of SNARE zippering Open
Membrane fusion requires R-, Qa-, Qb-, and Qc-family SNAREs that zipper into RQaQbQc coiled coils, driven by the sequestration of apolar amino acids. Zippering has been thought to provide all the force driving fusion. Sec17/αSNAP can form …
View article: Sec17/Sec18 can support membrane fusion without help from completion of SNARE zippering
Sec17/Sec18 can support membrane fusion without help from completion of SNARE zippering Open
Membrane fusion requires R-, Qa-, Qb-, and Qc-family SNAREs that zipper into RQaQbQc coiled coils, driven by the sequestration of apolar amino acids. Zippering has been thought to provide all the force driving fusion. Sec17/SNAP can form a…
View article: Asymmetric Rab activation of vacuolar HOPS to catalyze SNARE complex assembly
Asymmetric Rab activation of vacuolar HOPS to catalyze SNARE complex assembly Open
Rab proteins are known to recruit effector complexes for membrane fusion. Using pure yeast vacuole fusion proteins, we now show that the Rab Ypt7 and vacuolar lipids allosterically activate the effector HOPS to catalyze SNARE complex assem…
View article: A Rab prenyl membrane-anchor allows effector recognition to be regulated by guanine nucleotide
A Rab prenyl membrane-anchor allows effector recognition to be regulated by guanine nucleotide Open
Significance Although proteins are commonly bound to membranes by hydrophobic transmembrane polypeptide segments, Rab family GTPases are anchored by prenyl groups. Rabs undergo conformational switching, being more active with bound GTP and…
View article: HOPS recognizes each SNARE, assembling ternary trans-complexes for rapid fusion upon engagement with the 4th SNARE
HOPS recognizes each SNARE, assembling ternary trans-complexes for rapid fusion upon engagement with the 4th SNARE Open
Yeast vacuole fusion requires R-SNARE, Q-SNAREs, and HOPS. A HOPS SM-family subunit binds the R- and Qa-SNAREs. We now report that HOPS binds each of the four SNAREs. HOPS catalyzes fusion when the Q-SNAREs are not pre-assembled, ushering …
View article: Sec17 (α-SNAP) and Sec18 (NSF) restrict membrane fusion to R-SNAREs, Q-SNAREs, and SM proteins from identical compartments
Sec17 (α-SNAP) and Sec18 (NSF) restrict membrane fusion to R-SNAREs, Q-SNAREs, and SM proteins from identical compartments Open
Significance Although each intracellular fusion event is catalyzed by similar proteins, organelle-specific fusion is essential for accurate protein compartmentation. Prior studies have suggested that specificity resides in the SNARE protei…
View article: HOPS recognizes each SNARE, assembling ternary <i>trans</i>-complexes for sudden fusion upon engagement with the 4th SNARE
HOPS recognizes each SNARE, assembling ternary <i>trans</i>-complexes for sudden fusion upon engagement with the 4th SNARE Open
Vacuole fusion requires SNAREs, Sec17/18, a Rab, and HOPS. We find that co-incubation of HOPS, proteoliposomes bearing the Rab and R-SNARE, and proteoliposomes with the Rab and any two Q-SNAREs yields a trans complex which includes these 3…
View article: Tethering guides fusion-competent <i>trans</i> -SNARE assembly
Tethering guides fusion-competent <i>trans</i> -SNARE assembly Open
Significance R-SNARE (soluble N -ethylmaleimide–sensitive factor receptor) and the set of 3Q-SNAREs, anchored in separate membranes, can associate in trans in a coiled-coil tetramer. Proteoliposomes bearing only these SNAREs form abundant …
View article: Assembly of intermediates for rapid membrane fusion
Assembly of intermediates for rapid membrane fusion Open
Membrane fusion is essential for intracellular protein sorting, cell growth, hormone secretion, and neurotransmission. Rapid membrane fusion requires tethering and Sec1-Munc18 (SM) function to catalyze R-, Qa-, Qb-, and Qc-SNARE complex as…
View article: Sec17/Sec18 act twice, enhancing membrane fusion and then disassembling cis-SNARE complexes
Sec17/Sec18 act twice, enhancing membrane fusion and then disassembling cis-SNARE complexes Open
At physiological protein levels, the slow HOPS- and SNARE-dependent fusion which occurs upon complete SNARE zippering is stimulated by Sec17 and Sec18:ATP without requiring ATP hydrolysis. To stimulate, Sec17 needs its central residues whi…
View article: A short region upstream of the yeast vacuolar Qa-SNARE heptad-repeats promotes membrane fusion through enhanced SNARE complex assembly
A short region upstream of the yeast vacuolar Qa-SNARE heptad-repeats promotes membrane fusion through enhanced SNARE complex assembly Open
Whereas SNARE (soluble N-ethylmaleimide–sensitive factor attachment protein receptor) heptad-repeats are well studied, SNAREs also have upstream N-domains of indeterminate function. The assembly of yeast vacuolar SNAREs into complexes for …
View article: A cascade of multiple proteins and lipids catalyzes membrane fusion
A cascade of multiple proteins and lipids catalyzes membrane fusion Open
Recent studies suggest revisions to the SNARE paradigm of membrane fusion. Membrane tethers and/or SNAREs recruit proteins of the Sec 1/Munc18 family to catalyze SNARE assembly into trans-complexes. SNARE-domain zippering draws the bilayer…
View article: HOPS catalyzes the interdependent assembly of each vacuolar SNARE into a SNARE complex
HOPS catalyzes the interdependent assembly of each vacuolar SNARE into a SNARE complex Open
Rab GTPases, their effectors, SNAREs of the R, Qa, Qb, and Qc families, and SM SNARE-binding proteins catalyze intracellular membrane fusion. At the vacuole/lysosome, they are integrated by the homotypic fusion and vacuole protein sorting …