Membrane curvature induces cardiolipin sorting

Elena Beltrán-Heredia (1) , Feng-Ching Tsai (2) , Samuel Salinas-Almaguer (1) , Francisco J Cao (3, 1) , Patricia Bassereau (4, 2) , Francisco Monroy (1, 5)

1 UCM - Universidad Complutense de Madrid = Complutense University of Madrid [Madrid]
2 PCC - Laboratoire Physico-Chimie Curie [Institut Curie]
3 Instituto IMDEA Nanociencia [Madrid]
4 SU - Sorbonne Université
5 UC Berkeley - University of California [Berkeley]

Cardiolipin is a cone-shaped lipid predominantly localized in curved membrane sites of bacteria and in the mitochondrial cristae. This specific localization has been argued to be geometry-driven, since the CL's conical shape relaxes curvature frustration. Although previous evidence suggests a coupling between CL concentration and membrane shape in vivo, no precise experimental data are available for curvature-based CL sorting in vitro. Here, we test this hypothesis in experiments that isolate the effects of membrane curvature in lipid-bilayer nanotubes. CL sorting is observed with increasing tube curvature, reaching a maximum at optimal CL concentrations, a fact compatible with self-associative clustering. Observations are compatible with a model of membrane elasticity including van der Waals entropy, from which a negative intrinsic curvature of -1.1 nm-1 is predicted for CL. The results contribute to understanding the physicochemical interplay between membrane curvature and composition, providing key insights into mitochondrial and bacterial membrane organization and dynamics.

Mots clés: Research data; Membrane biophysics

Domaines: Biophysique [physics.bio-ph]; Biochimie, Biologie Moléculaire

Elena Beltrán-Heredia, Feng-Ching Tsai, Samuel Salinas-Almaguer, Francisco J Cao, Patricia Bassereau, et al.. Membrane curvature induces cardiolipin sorting. Communications Biology, 2019, 2 (1), pp.225. ⟨10.1038/s42003-019-0471-x⟩. ⟨hal-02173193⟩