title: The specificity of SNARE pairing in biological membranes is mediated by both proof-reading and spatial segregation.
abstract: Soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins mediate organelle fusion in the secretory pathway. Different fusion steps are catalyzed by specific sets of SNARE proteins. Here we have used the SNAREs mediating the fusion of early endosomes and exocytosis, respectively, to investigate how pairing specificity is achieved. Although both sets of SNAREs promiscuously assemble in vitro, there is no functional crosstalk. We now show that they not only colocalize to overlapping microdomains in the membrane of early endosomes of neuroendocrine cells, but also form cis-complexes promiscuously, with the proportion of the different complexes being primarily dependent on mass action. Addition of soluble SNARE molecules onto native membranes revealed preference for cognate SNAREs. Furthermore, we found that SNAREs are laterally segregated at endosome contact sites, with the exocytotic synaptobrevin being depleted. We conclude that specificity in endosome fusion is mediated by the following two synergistically operating mechanisms: (i) preference for the cognate SNARE in 'trans' interactions and (ii) lateral segregation of SNAREs, leading to relative enrichment of the cognate ones at the prospective fusion sites.
authors: Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.
authors: Ioanna
authors: I
authors: Bethani
authors: Thorsten
authors: T
authors: Lang
authors: Ulf
authors: U
authors: Geumann
authors: Jochen J
authors: JJ
authors: Sieber
authors: Reinhard
authors: R
authors: Jahn
authors: Silvio O
authors: SO
authors: Rizzoli
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D005089:Exocytosis; D008561:Membrane Fusion; D016716:PC12 Cells; D050682:Q-SNARE Proteins / Q000378:metabolism; D051381:Rats; D050600:SNARE Proteins / Q000378:metabolism*
chemical_list: D050682:Q-SNARE Proteins; D050600:SNARE Proteins
references: J Biol Chem. 2001 Jul 20;276(29):27480-7
references: 11323436
references: J Neurosci. 2000 Aug 1;20(15):5724-32
references: 10908612
references: J Cell Biol. 2002 Aug 19;158(4):751-60
references: 12177041
references: J Cell Biol. 2003 Feb 3;160(3):365-74
references: 12566429
references: Cell. 2003 Feb 21;112(4):519-33
references: 12600315
references: J Cell Biol. 2003 Jul 7;162(1):125-37
references: 12847087
references: J Cell Biol. 2004 Jan 5;164(1):79-88
references: 14699088
references: Nat Rev Mol Cell Biol. 2004 Feb;5(2):121-32
references: 15040445
references: EMBO J. 1994 Mar 15;13(6):1287-96
references: 8137813
references: J Cell Biol. 1998 Nov 16;143(4):957-71
references: 9817754
references: J Cell Biol. 1999 Jul 26;146(2):333-44
references: 10427089
references: J Cell Biol. 2004 Dec 20;167(6):1087-98
references: 15611334
references: EMBO J. 2005 May 18;24(10):1775-86
references: 15889152
references: Biochim Biophys Acta. 2005 Jun 30;1744(2):120-44
references: 15893389
references: Mol Biol Cell. 2006 Feb;17(2):977-89
references: 16339081
references: Biophys J. 2006 Apr 15;90(8):2843-51
references: 16443657
references: Mol Biol Cell. 2006 May;17(5):2113-24
references: 16481393
references: Proc Natl Acad Sci U S A. 2006 Feb 21;103(8):2701-6
references: 16469845
references: Science. 2006 Aug 4;313(5787):673-6
references: 16888141
references: Nat Rev Mol Cell Biol. 2006 Sep;7(9):631-43
references: 16912714
references: Traffic. 2006 Sep;7(9):1163-76
references: 17004320
references: Cell. 2006 Nov 17;127(4):831-46
references: 17110340
references: PLoS Biol. 2006 Oct;4(10):e330
references: 17002520
references: Eur J Neurosci. 2000 Jun;12(6):1913-23
references: 10886332
references: Biochimie. 2000 May;82(5):427-46
references: 10865130
references: Cell. 2007 Jan 12;128(1):183-95
references: 17218264
references: J Cell Biol. 2002 May 13;157(4):645-55
references: 11994317