Mitochondrial cristae modeled as an out-of-equilibrium membrane driven by a proton field

TL;DR

This paper models mitochondrial cristae as out-of-equilibrium membranes driven by proton flux, revealing how proton dynamics influence crista shape and potentially relate to mitochondrial energetic states.

Contribution

It introduces a pH-dependent Helfrich model to simulate crista membrane deformations driven by proton flux, linking membrane shape changes to mitochondrial activity.

Findings

Proton flux induces shape changes in cristae.

Oscillating proton flux can create neck formations.

Membrane deformations correlate with energetic states.

Abstract

As the places where most of the fuel of the cell, namely ATP, is synthesized, mitochondria are crucial organelles in eukaryotic cells. The shape of the invaginations of the mitochondria inner membrane, known as cristae, has been identified as a signature of the energetic state of the organelle. However, the interplay between the rate of ATP synthesis and the crista shape remains unclear. In this work, we investigate the crista membrane deformations using a pH-dependent Helfrich model, maintained out-of-equilibrium by a diffusive flux of protons. This model gives rise to shape changes of a cylindrical invagination, in particular to the formation of necks between wider zones under variable, and especially oscillating, proton flux.