Cholesterol stabilizes recombinant exocytic fusion pores by altering membrane bending rigidity. 2021

Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
Howard Hughes Medical Institute and the Department of Neuroscience, University of Wisconsin, Madison, Wisconsin.

SNARE-mediated membrane fusion proceeds via the formation of a fusion pore. This intermediate structure is highly dynamic and can flicker between open and closed states. In cells, cholesterol has been reported to affect SNARE-mediated exocytosis and fusion pore dynamics. Here, we address the question of whether cholesterol directly affects the flickering rate of reconstituted fusion pores in vitro. These experiments were enabled by the recent development of a nanodisc⋅black lipid membrane recording system that monitors dynamic transitions between the open and closed states of nascent recombinant pores with submillisecond time resolution. The fusion pores formed between nanodiscs that bore the vesicular SNARE synaptobrevin 2 and black lipid membranes that harbored the target membrane SNAREs syntaxin 1A and SNAP-25B were markedly affected by cholesterol. These effects include strong reductions in flickering out of the open state, resulting in a significant increase in the open dwell-time. We attributed these effects to the known role of cholesterol in altering the elastic properties of lipid bilayers because manipulation of phospholipids to increase membrane stiffness mirrored the effects of cholesterol. In contrast to the observed effects on pore kinetics, cholesterol had no effect on the current that passed through individual pores and, hence, did not affect pore size. In conclusion, our results show that cholesterol dramatically stabilizes fusion pores in the open state by increasing membrane bending rigidity.

UI MeSH Term Description Entries
D008561 Membrane Fusion The adherence and merging of cell membranes, intracellular membranes, or artificial membranes to each other or to viruses, parasites, or interstitial particles through a variety of chemical and physical processes. Fusion, Membrane,Fusions, Membrane,Membrane Fusions
D002784 Cholesterol The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. Epicholesterol
D005089 Exocytosis Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
D050600 SNARE Proteins A superfamily of small proteins which are involved in the MEMBRANE FUSION events, intracellular protein trafficking and secretory processes. They share a homologous SNARE motif. The SNARE proteins are divided into subfamilies: QA-SNARES; QB-SNARES; QC-SNARES; and R-SNARES. The formation of a SNARE complex (composed of one each of the four different types SNARE domains (Qa, Qb, Qc, and R)) mediates MEMBRANE FUSION. Following membrane fusion SNARE complexes are dissociated by the NSFs (N-ETHYLMALEIMIDE-SENSITIVE FACTORS), in conjunction with SOLUBLE NSF ATTACHMENT PROTEIN, i.e., SNAPs (no relation to SNAP 25.) SNAP Receptor,SNARE Protein,NSF Attachment Protein Receptor,Receptor, SNAP,SNAP Receptors,SNARE,SNAREs,Soluble N-ethylmaleimide-Sensitive-Factor Attachment Protein Receptor,Target Membrane SNARE Proteins,Target SNARE Proteins,Vesicle SNARE Proteins,Vesicular SNARE Proteins,t-SNARE,tSNAREs,v-SNARE,v-SNAREs,Protein, SNARE,SNARE Proteins, Target,SNARE Proteins, Vesicle,SNARE Proteins, Vesicular,Soluble N ethylmaleimide Sensitive Factor Attachment Protein Receptor,v SNAREs
D050988 Vesicle-Associated Membrane Protein 2 A synaptic membrane protein involved in MEMBRANE FUSION of SYNAPTIC VESICLES with the presynaptic membranes. It is the prototype member of the R-SNARE PROTEINS. Synaptobrevin 2,VAMP-2,VAMP2,VAMP 2,Vesicle Associated Membrane Protein 2

Related Publications

Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
October 2009, The Journal of membrane biology,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
June 1993, Biophysical journal,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
September 2022, Biophysical journal,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
April 2018, The Journal of chemical physics,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
June 2007, Physical review letters,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
February 2013, Molecular biology of the cell,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
November 2011, Soft matter,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
October 2019, The Journal of membrane biology,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
February 2004, Langmuir : the ACS journal of surfaces and colloids,
Lanxi Wu, and Kevin C Courtney, and Edwin R Chapman
May 2023, Advanced science (Weinheim, Baden-Wurttemberg, Germany),
Copied contents to your clipboard!