Light-induced lipid mixing implies a causal role of lipid splay in membrane fusion

Holger A Scheidt; Katja Kolocaj; David B Konrad; James A Frank; Dirk Trauner; Dieter Langosch; Daniel Huster

doi:10.1016/j.bbamem.2020.183438

Light-induced lipid mixing implies a causal role of lipid splay in membrane fusion

Biochim Biophys Acta Biomembr. 2020 Nov 1;1862(11):183438. doi: 10.1016/j.bbamem.2020.183438. Epub 2020 Aug 8.

Authors

Holger A Scheidt¹, Katja Kolocaj², David B Konrad³, James A Frank⁴, Dirk Trauner⁵, Dieter Langosch⁶, Daniel Huster⁷

Affiliations

¹ Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04107 Leipzig, Germany.
² Chair of Biopolymer Chemistry, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany; Munich Center For Integrated Protein Science (CIPS(M)), Germany.
³ Department of Chemistry and Center for Integrated Protein Science, Ludwig-Maximilians-University of Munich, Butenandtstraße 5-13, 81377 Munich, Germany; Department of Pharmacy, Ludwig-Maximilians-University of Munich, Butenandtstraße 5-13, 81377 Munich, Germany.
⁴ Department of Chemistry and Center for Integrated Protein Science, Ludwig-Maximilians-University of Munich, Butenandtstraße 5-13, 81377 Munich, Germany; Vollum Institute, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Rd., Portland, OR 97239, United States.
⁵ Department of Chemistry and Center for Integrated Protein Science, Ludwig-Maximilians-University of Munich, Butenandtstraße 5-13, 81377 Munich, Germany; Department of Chemistry, New York University, Silver Center, 100 Washington Square East, New York 10003, United States.
⁶ Chair of Biopolymer Chemistry, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany; Munich Center For Integrated Protein Science (CIPS(M)), Germany. Electronic address: [email protected].
⁷ Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04107 Leipzig, Germany. Electronic address: [email protected].

PMID: 32781156
DOI: 10.1016/j.bbamem.2020.183438

Abstract

The fusion of lipid membranes is central to many biological processes and requires substantial structural reorganization of lipids brought about by the action of fusogenic proteins. Previous molecular dynamics simulations have suggested that splayed lipids, whose tails transiently contact the headgroup region of the bilayer, initiate lipid mixing. Here, we explore the lipid splay hypothesis experimentally. We show that the light-induced trans/cis conversion of the azobenzene-based tail of a model lipid molecule enhances the probability by which its own acyl chains, or the acyl chains of the host lipid, transiently contact the lipid headgroup in a liposomal bilayer. At the same time, the trans/cis conversion triggers lipid mixing of sonicated or extruded liposomes, without requiring fusogenic proteins. This establishes a causal relationship between lipid splay and membrane fusion.

Keywords: Lipid mixing; Lipid splay; Membrane fusion; Photo-switch.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Lipid Bilayers / chemistry*
Membrane Fusion*
Models, Chemical*

Substances

Lipid Bilayers