Home LiteratureArticle Details
PMID: 19258315 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

Is assembly of the SNARE complex enough to fuel membrane fusion?

The Journal of biological chemistry ·Vol. 284 ·No. 19 ·2009-05-08 ·Pages 13143-52

Wiederhold K, Fasshauer D

Abstract

The three key players in the exocytotic release of neurotransmitters from synaptic vesicles are the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins synaptobrevin 2, syntaxin 1a, and SNAP-25. Their assembly into a tight four-helix bundle complex is thought to pull the two membranes into close proximity. It is debated, however, whether the energy generated suffices for membrane fusion. Here, we have determined the thermodynamic properties of the individual SNARE assembly steps by isothermal titration calorimetry. We found extremely large favorable enthalpy changes counterbalanced by positive entropy changes, reflecting the major conformational changes upon assembly. To circumvent the fact that ternary complex formation is essentially irreversible, we used a stabilized syntaxin-SNAP-25 heterodimer to study synaptobrevin binding. This strategy revealed that the N-terminal synaptobrevin coil binds reversibly with nanomolar affinity. This suggests that individual, membrane-bridging SNARE complexes can provide much less pulling force than previously claimed.

MeSH Terms
Calorimetry Circular Dichroism Dimerization Humans Liposomes Membrane Fusion/physiology Protein Conformation Qa-SNARE Proteins/metabolism R-SNARE Proteins/metabolism SNARE Proteins/metabolism Synaptic Vesicles/metabolism Synaptosomal-Associated Protein 25/metabolism
Chemicals
Liposomes Qa-SNARE Proteins R-SNARE Proteins SNAP25 protein, human SNARE Proteins Synaptosomal-Associated Protein 25
Authors & Affiliations
2 authors, click to expand affiliations / ORCID
Wiederhold Katrin
Research Group Structural Biochemistry, Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen, Germany.
Fasshauer Dirk
References (57)
57 references, click to expand
  1. N- to C-terminal SNARE complex assembly promotes rapid membrane fusion.
    Science. 2006 Aug 4;313(5787):673-6 PMID: 16888141
  2. Interactions between synaptic vesicle fusion proteins explored by atomic force microscopy.
    Proc Natl Acad Sci U S A. 2003 Jul 22;100(15):8736-41 PMID: 12853568
  3. Complexin and Ca2+ stimulate SNARE-mediated membrane fusion.
    Nat Struct Mol Biol. 2008 Jul;15(7):707-13 PMID: 18552825
  4. Molecular architecture of native HIV-1 gp120 trimers.
    Nature. 2008 Sep 4;455(7209):109-13 PMID: 18668044
  5. Regulation of membrane fusion by the membrane-proximal coil of the t-SNARE during zippering of SNAREpins.
    J Cell Biol. 2002 Sep 2;158(5):929-40 PMID: 12213837
  6. Mixed and non-cognate SNARE complexes. Characterization of assembly and biophysical properties.
    J Biol Chem. 1999 May 28;274(22):15440-6 PMID: 10336434
  7. Molecular form follows function: (un)snaring the SNAREs.
    Trends Neurosci. 2008 Sep;31(9):435-43 PMID: 18675467
  8. Homo- and heterooligomeric SNARE complexes studied by site-directed spin labeling.
    J Biol Chem. 2001 Apr 20;276(16):13169-77 PMID: 11278719
  9. SNARE assembly and disassembly exhibit a pronounced hysteresis.
    Nat Struct Biol. 2002 Feb;9(2):144-51 PMID: 11786917
  10. Interactions between neuronal fusion proteins explored by molecular dynamics.
    Biophys J. 2008 May 1;94(9):3436-46 PMID: 18212009
  11. Neuronal SNAREs do not trigger fusion between synthetic membranes but do promote PEG-mediated membrane fusion.
    Biophys J. 2006 Mar 1;90(5):1661-75 PMID: 16339880
  12. Membrane fusion.
    Curr Opin Cell Biol. 2002 Aug;14(4):488-95 PMID: 12383801
  13. Natively unfolded proteins.
    Curr Opin Struct Biol. 2005 Feb;15(1):35-41 PMID: 15718131
  14. SNAREs--engines for membrane fusion.
    Nat Rev Mol Cell Biol. 2006 Sep;7(9):631-43 PMID: 16912714
  15. Membranes are more mosaic than fluid.
    Nature. 2005 Dec 1;438(7068):578-80 PMID: 16319876
  16. Synaptic vesicle fusion.
    Nat Struct Mol Biol. 2008 Jul;15(7):665-74 PMID: 18618940
  17. Intrinsically unstructured proteins and their functions.
    Nat Rev Mol Cell Biol. 2005 Mar;6(3):197-208 PMID: 15738986
  18. Regulation of membrane fusion in synaptic excitation-secretion coupling: speed and accuracy matter.
    Neuron. 2007 Jul 5;55(1):11-24 PMID: 17610814
  19. A structural change occurs upon binding of syntaxin to SNAP-25.
    J Biol Chem. 1997 Feb 14;272(7):4582-90 PMID: 9020186
  20. Membrane topologies of neuronal SNARE folding intermediates.
    Biochemistry. 2002 Sep 10;41(36):10928-33 PMID: 12206663
  21. Energetics and dynamics of SNAREpin folding across lipid bilayers.
    Nat Struct Mol Biol. 2007 Oct;14(10):890-6 PMID: 17906638
  22. Multiple intermediates in SNARE-induced membrane fusion.
    Proc Natl Acad Sci U S A. 2006 Dec 26;103(52):19731-6 PMID: 17167056
  23. A trimeric structural domain of the HIV-1 transmembrane glycoprotein.
    Nat Struct Biol. 1995 Dec;2(12):1075-82 PMID: 8846219
  24. Hemifusion in SNARE-mediated membrane fusion.
    Nat Struct Mol Biol. 2005 May;12(5):417-22 PMID: 15821745
  25. Rapid and efficient fusion of phospholipid vesicles by the alpha-helical core of a SNARE complex in the absence of an N-terminal regulatory domain.
    Proc Natl Acad Sci U S A. 1999 Oct 26;96(22):12565-70 PMID: 10535962
  26. The neuronal t-SNARE complex is a parallel four-helix bundle.
    Nat Struct Biol. 2001 Apr;8(4):308-11 PMID: 11276248
  27. HIV-1 gp41: mediator of fusion and target for inhibition.
    AIDS Rev. 2003 Oct-Dec;5(4):214-21 PMID: 15012000
  28. Mechanics of membrane fusion.
    Nat Struct Mol Biol. 2008 Jul;15(7):675-83 PMID: 18596814
  29. How much can SNAREs flex their muscles?
    Nat Struct Mol Biol. 2007 Oct;14(10):880-2 PMID: 17912256
  30. Munc18a controls SNARE assembly through its interaction with the syntaxin N-peptide.
    EMBO J. 2008 Apr 9;27(7):923-33 PMID: 18337752
  31. A dynamic t-SNARE complex.
    Structure. 2008 Feb;16(2):163-5 PMID: 18275808
  32. A transient N-terminal interaction of SNAP-25 and syntaxin nucleates SNARE assembly.
    J Biol Chem. 2004 Feb 27;279(9):7613-21 PMID: 14665625
  33. Structure of an HIV gp120 envelope glycoprotein in complex with the CD4 receptor and a neutralizing human antibody.
    Nature. 1998 Jun 18;393(6686):648-59 PMID: 9641677
  34. Single molecule mechanical probing of the SNARE protein interactions.
    Biophys J. 2006 Jul 15;91(2):744-58 PMID: 16648158
  35. The four-helix bundle of the neuronal target membrane SNARE complex is neither disordered in the middle nor uncoiled at the C-terminal region.
    J Biol Chem. 2002 Jul 5;277(27):24294-8 PMID: 11983696
  36. Interactions of HIV-1 proteins gp120 and Nef with cellular partners define a novel allosteric paradigm.
    Curr Protein Pept Sci. 2004 Feb;5(1):1-8 PMID: 14965316
  37. Viral membrane fusion.
    Nat Struct Mol Biol. 2008 Jul;15(7):690-8 PMID: 18596815
  38. Small molecules that bind the inner core of gp41 and inhibit HIV envelope-mediated fusion.
    Proc Natl Acad Sci U S A. 2006 Sep 19;103(38):13938-43 PMID: 16963566
  39. Atomic structure of the ectodomain from HIV-1 gp41.
    Nature. 1997 May 22;387(6631):426-30 PMID: 9163431
  40. Crystal structure of a SNARE complex involved in synaptic exocytosis at 2.4 A resolution.
    Nature. 1998 Sep 24;395(6700):347-53 PMID: 9759724
  41. Membrane fusion: SNAREs and regulation.
    Cell Mol Life Sci. 2008 Sep;65(18):2814-32 PMID: 18726177
  42. Energetics of the HIV gp120-CD4 binding reaction.
    Proc Natl Acad Sci U S A. 2000 Aug 1;97(16):9026-31 PMID: 10922058
  43. Distinct domains of complexins bind SNARE complexes and clamp fusion in vitro.
    J Biol Chem. 2008 Jul 25;283(30):21211-9 PMID: 18499660
  44. Virus membrane fusion.
    FEBS Lett. 2007 May 22;581(11):2150-5 PMID: 17320081
  45. Structural changes are associated with soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor complex formation.
    J Biol Chem. 1997 Oct 31;272(44):28036-41 PMID: 9346956
  46. Molecular anatomy of a trafficking organelle.
    Cell. 2006 Nov 17;127(4):831-46 PMID: 17110340
  47. Mechanisms of membrane fusion: disparate players and common principles.
    Nat Rev Mol Cell Biol. 2008 Jul;9(7):543-56 PMID: 18496517
  48. Neurotransmitter release - four years of SNARE complexes.
    Curr Opin Neurobiol. 1997 Jun;7(3):310-5 PMID: 9232812
  49. Membrane fusion induced by neuronal SNAREs transits through hemifusion.
    J Biol Chem. 2005 Aug 26;280(34):30538-41 PMID: 15980065
  50. Progress in understanding the neuronal SNARE function and its regulation.
    Cell Mol Life Sci. 2009 Feb;66(3):460-9 PMID: 18953690
  51. SNAREpins: minimal machinery for membrane fusion.
    Cell. 1998 Mar 20;92(6):759-72 PMID: 9529252
  52. Structures of the CCR5 N terminus and of a tyrosine-sulfated antibody with HIV-1 gp120 and CD4.
    Science. 2007 Sep 28;317(5846):1930-4 PMID: 17901336
  53. How synaptotagmin promotes membrane fusion.
    Science. 2007 May 25;316(5828):1205-8 PMID: 17478680
  54. Mechanisms of viral membrane fusion and its inhibition.
    Annu Rev Biochem. 2001;70:777-810 PMID: 11395423
  55. Regulated exocytosis: merging ideas on fusing membranes.
    Curr Opin Cell Biol. 2007 Aug;19(4):402-8 PMID: 17629692
  56. SNARE-mediated lipid mixing depends on the physical state of the vesicles.
    Biophys J. 2006 Mar 15;90(6):2062-74 PMID: 16361343
  57. Comparative energy measurements in single molecule interactions.
    Biophys J. 2008 Jul;95(1):419-25 PMID: 18375504
Article Info
Journal
The Journal of biological chemistry
Abbr.
J Biol Chem
ISSN
0021-9258
DOI
10.1074/jbc.M900703200
Published
2009-05-08
Epub
2009-00-03
Pages
13143-52
Language
English
Region
United States
NLM ID
2985121R
PMCID
PMC2676046
Subset
IM
External Links
PubMed source DOI: 10.1074/jbc.M900703200 PMC Full Text View journal details
Analysis Services
Analysis Services

Contact

No. 2 Wenbo Road, Zhangqiu District, Jinan, Shandong

Qilu Normal University · Genelibs Bioinformatics Lab

750 Shunhua Rd, Jinan

2F, Bldg F, University Science Park

Tel: 0531-88819269

WeChat Official Account

Follow our WeChat subscription account for real-time updates and the latest in medical and biological research.


Business Email

E-mail: [email protected]

Copyright © 2026.Genelibs Jinan Honghui Biotechnology Co., Ltd. 鲁ICP备20007159号-2