scholarly journals Rab-Effector-Kinase Interplay Modulates Intralumenal Fragment Formation during Vacuole Fusion

2018 ◽  
Vol 47 (1) ◽  
pp. 80-97.e6 ◽  
Author(s):  
Mahmoud Abdul Karim ◽  
Erin Kate McNally ◽  
Dieter Ronny Samyn ◽  
Sevan Mattie ◽  
Christopher Leonard Brett
Keyword(s):  
Vacuole Fusion ◽  
Fragment Formation ◽  
Rab Effector

scholarly journals Membranes linked by trans-SNARE complexes require lipids prone to non-bilayer structure for progression to fusion

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Michael Zick ◽  
Christopher Stroupe ◽  
Amy Orr ◽  
Deborah Douville ◽  
William T Wickner
Keyword(s):  
Neutral Lipids ◽  
Complex Mixture ◽  
Snare Proteins ◽  
Rab Gtpase ◽  
Bilayer Structure ◽  
Helical Bundle ◽  
Vacuole Fusion ◽  
Rab Effector

Like other intracellular fusion events, the homotypic fusion of yeast vacuoles requires a Rab GTPase, a large Rab effector complex, SNARE proteins which can form a 4-helical bundle, and the SNARE disassembly chaperones Sec17p and Sec18p. In addition to these proteins, specific vacuole lipids are required for efficient fusion in vivo and with the purified organelle. Reconstitution of vacuole fusion with all purified components reveals that high SNARE levels can mask the requirement for a complex mixture of vacuole lipids. At lower, more physiological SNARE levels, neutral lipids with small headgroups that tend to form non-bilayer structures (phosphatidylethanolamine, diacylglycerol, and ergosterol) are essential. Membranes without these three lipids can dock and complete trans-SNARE pairing but cannot rearrange their lipids for fusion.

scholarly journals A Ypt/Rab effector complex containing the Sec1 homolog Vps33p is required for homotypic vacuole fusion

2000 ◽  
Vol 97 (17) ◽  
pp. 9402-9407 ◽  
Author(s):  
D. F. Seals ◽  
G. Eitzen ◽  
N. Margolis ◽  
W. T. Wickner ◽  
A. Price
Keyword(s):  
Vacuole Fusion ◽  
Rab Effector

scholarly journals Ykt6 mediates autophagosome-vacuole fusion

2018 ◽  
Vol 5 (6) ◽  
pp. e1526006 ◽  
Author(s):  
Levent Bas ◽  
Daniel Papinski ◽  
Claudine Kraft
Keyword(s):  
Vacuole Fusion

Fragment formation in crushing a brittle medium under hydrostatic compression

1979 ◽  
Vol 15 (3) ◽  
pp. 228-232 ◽  
Author(s):  
V. M. Tsvetkov ◽  
B. G. Lukishov ◽  
L. D. Livshits
Keyword(s):  
Hydrostatic Compression ◽  
Fragment Formation

scholarly journals Sec18p and Vam7p remodel trans-SNARE complexes to permit a lipid-anchored R-SNARE to support yeast vacuole fusion

2007 ◽  
Vol 26 (24) ◽  
pp. 4935-4945 ◽  
Author(s):  
Youngsoo Jun ◽  
Hao Xu ◽  
Naomi Thorngren ◽  
William Wickner
Keyword(s):  
Yeast Vacuole ◽  
Vacuole Fusion

Monitoring of epithelial cell caspase activation via detection of durable keratin fragment formation

2008 ◽  
Vol 215 (2) ◽  
pp. 164-174 ◽  
Author(s):  
G-Z Tao ◽  
DH Li ◽  
Q Zhou ◽  
DM Toivola ◽  
P Strnad ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Caspase Activation ◽  
Fragment Formation

scholarly journals HOPS Proofreads the trans-SNARE Complex for Yeast Vacuole Fusion

2008 ◽  
Vol 19 (6) ◽  
pp. 2500-2508 ◽  
Author(s):  
Vincent J. Starai ◽  
Christopher M. Hickey ◽  
William Wickner
Keyword(s):  
Snare Complex ◽  
Wild Type ◽  
Fusion Event ◽  
Sm Proteins ◽  
Terminal Domain ◽  
Domain Structures ◽  
Vacuole Fusion ◽  
Protein Receptors ◽  
Optimal Fusion ◽  
Guanosine Triphosphatase

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.

scholarly journals Yeast vacuolar HOPS, regulated by its kinase, exploits affinities for acidic lipids and Rab:GTP for membrane binding and to catalyze tethering and fusion

2015 ◽  
Vol 26 (2) ◽  
pp. 305-315 ◽  
Author(s):  
Amy Orr ◽  
William Wickner ◽  
Scott F. Rusin ◽  
Arminja N. Kettenbach ◽  
Michael Zick
Keyword(s):  
Protein Sorting ◽  
Rab Gtpase ◽  
Attachment Protein ◽  
Functional Relationships ◽  
Sensitive Factor ◽  
Protein Receptors ◽  
Membrane Tethering ◽  
Rab Effector ◽  
Supporting Membrane ◽  
Acidic Lipids

Fusion of yeast vacuoles requires the Rab GTPase Ypt7p, four SNAREs (soluble N-ethylmaleimide–sensitive factor attachment protein receptors), the SNARE disassembly chaperones Sec17p/Sec18p, vacuolar lipids, and the Rab-effector complex HOPS (homotypic fusion and vacuole protein sorting). Two HOPS subunits have direct affinity for Ypt7p. Although vacuolar fusion has been reconstituted with purified components, the functional relationships between individual lipids and Ypt7p:GTP have remained unclear. We now report that acidic lipids function with Ypt7p as coreceptors for HOPS, supporting membrane tethering and fusion. After phosphorylation by the vacuolar kinase Yck3p, phospho-HOPS needs both Ypt7p:GTP and acidic lipids to support fusion.

Sign in / Sign up

Export Citation Format

Share Document