scholarly journals The Docking Stage of Yeast Vacuole Fusion Requires the Transfer of Proteins from a Cis-Snare Complex to a Rab/Ypt Protein

2000 ◽  
Vol 148 (6) ◽  
pp. 1231-1238 ◽  
Author(s):  
Albert Price ◽  
Darren Seals ◽  
William Wickner ◽  
Christian Ungermann
Keyword(s):  
Binding Protein ◽  
Snare Complex ◽  
Guanosine Triphosphate ◽  
Yeast Vacuole ◽  
Vacuole Fusion ◽  
Direct Association ◽  
Rab Family

The homotypic fusion of yeast vacuoles requires Sec18p (NSF)-driven priming to allow vacuole docking, but the mechanism that links priming and docking is unknown. We find that a large multisubunit protein called the Vam2/6p complex is bound to cis-paired SNAP receptors (SNAREs) on isolated vacuoles. This association of the Vam2/6p complex with the cis-SNARE complex is disrupted during priming. The Vam2/6p complex then binds to Ypt7p, a guanosine triphosphate binding protein of the Rab family, to initiate productive contact between vacuoles. Thus, cis-SNARE complexes can contain Rab/Ypt effectors, and these effectors can be mobilized by NSF/Sec18p-driven priming, allowing their direct association with a Rab/Ypt protein to activate docking.

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

Author response for "Copper blocks V‐ATPase activity and SNARE complex formation to inhibit yeast vacuole fusion"

2019 ◽  
Author(s):  
Gregory E. Miner ◽  
Katherine D. Sullivan ◽  
Chi Zhang ◽  
Logan R. Hurst ◽  
Matthew L. Starr ◽  
...  
Keyword(s):  
Complex Formation ◽  
Atpase Activity ◽  
Snare Complex ◽  
Author Response ◽  
Yeast Vacuole ◽  
Vacuole Fusion ◽  
Snare Complex Formation

Author response for "Copper blocks V‐ATPase activity and SNARE complex formation to inhibit yeast vacuole fusion"

2019 ◽  
Author(s):  
Gregory E. Miner ◽  
Katherine D. Sullivan ◽  
Chi Zhang ◽  
Logan R. Hurst ◽  
Matthew L. Starr ◽  
...  
Keyword(s):  
Complex Formation ◽  
Atpase Activity ◽  
Snare Complex ◽  
Author Response ◽  
Yeast Vacuole ◽  
Vacuole Fusion ◽  
Snare Complex Formation

scholarly journals Phosphatidylinositol 3,5-Bisphosphate Regulates Yeast Vacuole Fusion at the Transition between trans-SNARE Complex Formation and Hemifusion

2018 ◽  
Author(s):  
Gregory E. Miner ◽  
Katherine D. Sullivan ◽  
Annie Guo ◽  
Brandon C. Jones ◽  
Matthew L. Starr ◽  
...  
Keyword(s):  
Complex Formation ◽  
Membrane Fusion ◽  
Molecular Switch ◽  
Snare Complex ◽  
Negative Regulator ◽  
Cellular Functions ◽  
Hyperosmotic Shock ◽  
Yeast Vacuole ◽  
Vacuole Fusion ◽  
Snare Complex Formation

ABSTRACTPhosphoinositides (PIs) regulate myriad cellular functions including membrane fusion, as exemplified by the yeast vacuole, which uses various PIs at different stages of fusion. In light of this, the effect of phos-phatidylinositol 3,5-bisphosphate [PI(3,5)P2] on vacuole fusion remains unknown. PI(3,5)P2 is made by the PI3P 5-kinase Fab1/PIKfyve and has been characterized as a regulator of vacuole fission during hyperosmotic shock where it interacts with the TRP family Ca2+ channel Yvc1. Here we demonstrate that exogenously added dioctanoyl (C8) PI(3,5)P2 abolishes homotypic vacuole fusion. This effect was not linked to interactions with Yvc1, as fusion was equally affected using yvc1Δ vacuoles. Thus, the effects of C8-PI(3,5)P2 on fusion versus fission operate through distinct mechanisms. Further testing showed that C8-PI(3,5)P2 inhibited vacuole fusion after the formation of trans-SNARE pairs. Although SNARE complex formation was unaffected we found that C8-PI(3,5)P2 strongly inhibited hemifusion. Overproduction of endogenous PI(3,5)P2 by the fab1T2250A hyperactive kinase mutant also inhibited at the hemifusion stage, bolstering the model in which PI(3,5)P2 inhibits fusion when present elevated levels. Taken together, this work identifies a novel function for PI(3,5)P2 as a negative regulator of vacuolar fusion. Moreover, it suggests that this lipid acts as a molecular switch between fission and fusion.

Author response for "Copper blocks V‐ATPase activity and SNARE complex formation to inhibit yeast vacuole fusion"

2019 ◽  
Author(s):  
Gregory E. Miner ◽  
Katherine D. Sullivan ◽  
Chi Zhang ◽  
Logan R. Hurst ◽  
Matthew L. Starr ◽  
...  
Keyword(s):  
Complex Formation ◽  
Atpase Activity ◽  
Snare Complex ◽  
Author Response ◽  
Yeast Vacuole ◽  
Vacuole Fusion ◽  
Snare Complex Formation

scholarly journals Asymmetric Rab activation of vacuolar HOPS to catalyze SNARE complex assembly

2020 ◽  
Vol 31 (10) ◽  
pp. 1060-1068
Author(s):  
Thomas Torng ◽  
Hongki Song ◽  
William Wickner
Keyword(s):  
Membrane Fusion ◽  
Fusion Proteins ◽  
Snare Complex ◽  
Rab Proteins ◽  
Complex Assembly ◽  
Yeast Vacuole ◽  
Vacuole Fusion

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 assembly when the R-SNARE is bound to the same membrane as Ypt7.

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