HOPS initiates vacuole docking by tethering membranes before trans-SNARE complex assembly.
Vacuole homotypic fusion has been reconstituted with all purified components: vacuolar lipids, four soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, Sec17p, Sec18p, the Rab Ypt7p, and the hexameric homotypic fusion and vacuole protein sorting complex (HOPS). HOPS is a Rab-effector with direct affinity for SNAREs (presumably via its Sec1-Munc18 homologous subunit Vps33p) and for certain vacuolar lipids. Each of these pure vacuolar proteins was required for optimal proteoliposome clustering, raising the question of which was most directly involved. We now present model subreactions of clustering and fusion that reveal that HOPS is the direct agent of tethering. The Rab and vacuole lipids contribute to tethering by supporting the membrane association of HOPS. HOPS indirectly facilitates trans-SNARE complex formation by tethering membranes, because the synthetic liposome tethering factor polyethylene glycol can also stimulate trans-SNARE complex formation and fusion. SNAREs further stabilize the associations of HOPS-tethered membranes. HOPS then protects newly formed trans-SNARE complexes from disassembly by Sec17p/Sec18p.
Hickey
Christopher M
CM
Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA.
Wickner
William
W
D002462:Cell Membrane / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008561:Membrane Fusion; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism*
D008081:Liposomes; D029701:Saccharomyces cerevisiae Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
EMBO J. 1999 Oct 1;18(19):5216-25
10508155
Proc Natl Acad Sci U S A. 2009 Oct 13;106(41):17308-13
19805029
J Cell Biol. 2003 Feb 3;160(3):365-74
12566429
EMBO J. 1996 Jul 1;15(13):3296-305
8670830
J Cell Biol. 2002 May 13;157(4):645-55
11994317
Proc Natl Acad Sci U S A. 2007 Aug 21;104(34):13551-8
17699614
J Cell Biol. 2004 Dec 20;167(6):1087-98
15611334
J Biol Chem. 2002 Mar 8;277(10):8611-7
11602609
J Biol Chem. 1996 Sep 27;271(39):24048-54
8798641
Proc Natl Acad Sci U S A. 2009 Oct 20;106(42):17626-33
19826089
J Cell Biol. 1997 Jan 27;136(2):307-17
9015302
Biophys J. 2006 Mar 1;90(5):1661-75
16339880
Eur Biophys J. 2007 Apr;36(4-5):315-26
17039359
Mol Biol Cell. 2009 Apr;20(7):1937-48
19193765
J Cell Biol. 2009 May 4;185(3):535-49
19414611
EMBO J. 2008 Aug 6;27(15):2031-42
18650938
Cell. 2007 Jan 12;128(1):183-95
17218264
Nat Rev Neurosci. 2002 Aug;3(8):641-53
12154365
J Mol Biol. 2008 Jun 27;380(1):42-50
18508081
J Cell Biol. 2008 Sep 22;182(6):1141-51
18809726
EMBO J. 2005 May 18;24(10):1775-86
15889152
Nat Struct Mol Biol. 2007 Feb;14(2):138-46
17220896
Proc Natl Acad Sci U S A. 2000 Aug 15;97(17):9402-7
10944212
J Biol Chem. 2009 Jun 12;284(24):16118-16125
19386605
Mol Biol Cell. 2008 Jun;19(6):2500-8
18385512
Nat Struct Mol Biol. 2008 Jul;15(7):658-64
18618939
Proc Natl Acad Sci U S A. 2006 Aug 8;103(32):11821-7
16882731
EMBO J. 2006 Apr 19;25(8):1579-89
16601699
Proc Natl Acad Sci U S A. 2007 May 22;104(21):8755-60
17502611
EMBO J. 2010 Jun 16;29(12):1948-60
20473271
EMBO J. 1996 Dec 2;15(23):6483-94
8978675
J Cell Biol. 2008 Jan 14;180(1):145-58
18195105
Nature. 2009 Jun 25;459(7250):1091-7
19458617
Nat Struct Mol Biol. 2006 Mar;13(3):209-17
16491093
Science. 2009 Jan 23;323(5913):474-7
19164740
Nature. 1998 Jul 30;394(6692):494-8
9697774
Cell. 2002 Feb 8;108(3):357-69
11853670
Science. 2008 May 2;320(5876):670-3
18451304
J Cell Biol. 2005 Jan 31;168(3):401-14
15684030
Nat Struct Biol. 2001 Mar;8(3):258-64
11224573
J Biol Chem. 1995 Aug 11;270(32):18711-4
7642515
Mol Biol Cell. 2007 Nov;18(11):4483-92
17761530
Autophagy. 2008 Jan;4(1):5-19
17932463
Mol Cell. 1998 Jul;2(1):157-62
9702203
EMBO J. 2007 Sep 19;26(18):4053-65
17717527