Membrane tension inhibits lipid mixing by increasing the hemifusion stalk energy

• Verfasst von: Shendrik, Petr [VerfasserIn]
• Verfasst von: Golani, Gonen [VerfasserIn]
• Verfasst von: Dharan, Raviv [VerfasserIn]
• Verfasst von: Schwarz, Ulrich S. [VerfasserIn]
• Verfasst von: Sorkin, Raya [VerfasserIn]
• Titel: Membrane tension inhibits lipid mixing by increasing the hemifusion stalk energy
• Verf.angabe: Petr Shendrik, Gonen Golani, Raviv Dharan, Ulrich S. Schwarz, Raya Sorkin
• E-Jahr: 2023
• Jahr: 10 October 2023
• Umfang: 10 S.
• Illustrationen: Illustrationen
• Fussnoten: Online veröffentlicht: 5. September 2023 ; Gesehen am 16.10.2023
• Titel Quelle: Enthalten in: American Chemical SocietyACS nano
• Ort Quelle: Washington, DC : Soc., 2007
• Jahr Quelle: 2023
• Band/Heft Quelle: 17(2023), 19 vom: Okt., Seite 18942-18951
• ISSN Quelle: 1936-086X
• DOI: doi:10.1021/acsnano.3c04293
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1865720674

Abstract

Fusion of biological membranes is fundamental in various physiological events. The fusion process involves several intermediate stages with energy barriers that are tightly dependent on the mechanical and physical properties of the system, one of which is membrane tension. As previously established, the late stages of fusion, including hemifusion diaphragm and pore expansions, are favored by membrane tension. However, a current understanding of how the energy barrier of earlier fusion stages is affected by membrane tension is lacking. Here, we apply a newly developed experimental approach combining micropipette-aspirated giant unilamellar vesicles and optically trapped membrane-coated beads, revealing that membrane tension inhibits lipid mixing. We show that lipid mixing is 6 times slower under a tension of 0.12 mN/m compared with tension-free membranes. Furthermore, using continuum elastic theory, we calculate the dependence of the hemifusion stalk formation energy on membrane tension and intermembrane distance and find the increase in the corresponding energy barrier to be 1.6 kBT in our setting, which can explain the increase in lipid mixing time delay. Finally, we show that tension can be a significant factor in the stalk energy if the pre-fusion intermembrane distance is on the order of several nanometers, while for membranes that are tightly docked, tension has a negligible effect.