Cardiolipin increases the peak of reversible traveling H+ fronts at the membrane surface

Verdict. Cardiolipin (CL) is a phospholipid found in the inner mitochondrial membrane (IMM) where it increases the efficiency of ATP regeneration. It intersects mitochondrial stress/dysfunction themes (dynamics (fission/fusion); OXPHOS / ETC; cardiolipin / membrane).

What the authors report

CL enrichment of the membranes increased their surface H+ activity by a ~4 factor. Moreover, we observed non-gaussian spatial H+ concentration profiles with distance from a point H+ source with both PC and CL membranes suggesting that both lipids also induce interactions between probe molecules.

Key results stated in the abstract include the following. Cardiolipin (CL) is a phospholipid found in the inner mitochondrial membrane (IMM) where it increases the efficiency of ATP regeneration. We have investigated the hypothesis that this increase may result in part from CL concentrating H+ at the IMM surface through electrostatic interactions as the CL polar head is a dianion at physiological pH. To this aim, we compared the concentrations and movements of H+ at the surface of giant planar phosphatidylcholine (PC) membranes and 20% CL enriched PC membranes by recording their surface pH with the membrane-grafted pH probe fluorescein DHPE.

Why it matters for mitochondrial biology

Within mitochondrial research, this work maps primarily to OXPHOS, mitochondrial dynamics, redox biology, computational. It is relevant to mitochondrial dysfunction discourse because the abstract invokes dynamics (fission/fusion), OXPHOS / ETC, cardiolipin / membrane. That does not by itself establish a validated disease mechanism; it indicates thematic proximity. OXPHOS/ETC involvement, if confirmed, would place the work in the core of bioenergetic pathophysiology rather than peripheral organelle biology. Server: biorxiv. Posted 2026-08-19. Synthesis confidence is bounded by abstract completeness.

Study design (abstract-level)

A reaction-diffusion model of these observations suggests that membranes support these fronts through a mechanism of autocatalytic (de)protonation of the membrane surface.

Principal findings

1. Cardiolipin (CL) is a phospholipid found in the inner mitochondrial membrane (IMM) where it increases the efficiency of ATP regeneration.
2. We have investigated the hypothesis that this increase may result in part from CL concentrating H+ at the IMM surface through electrostatic interactions as the CL polar head is a dianion at physiological pH.
3. To this aim, we compared the concentrations and movements of H+ at the surface of giant planar phosphatidylcholine (PC) membranes and 20% CL enriched PC membranes by recording their surface pH with the membrane-grafted pH probe fluorescein DHPE.
4. In mitochondria, these fronts would result in transitions between high and low pH states, the low one having a larger H+ concentration in CL-enriched regions of the IMM.
5. Such an increase at the inner leaflet of the IMM may increase efficiency of the respiratory chain whereas the increase at the outer leaflet may boost the ATP synthase rate.

Limitations of this brief

• This Mitos brief is an abstract-level synthesis of a preprint; it is not peer review and not a substitute for reading the full paper.
• Preprint status: findings may change with revision or journal review.
• Effect sizes, n numbers, statistics, and full experimental controls are typically incomplete at abstract resolution.
• Primary source: biorxiv DOI 10.64898/2026.08.15.744977 (posted 2026-08-19).

Open scientific questions

• Which specific experimental panels in the full paper establish the strongest causal claim, and how robust are the controls?
• Are OXPHOS defects primary drivers or secondary consequences of broader cellular stress?
• How do these findings sit relative to prior literature on the same pathway—replication, contradiction, or incremental extension?

Bottom line

For mitochondrial biologists focused on OXPHOS, mitochondrial dynamics, redox biology, this preprint is worth full-text review if the topic matches your program. Abstract-level takeaway: Cardiolipin (CL) is a phospholipid found in the inner mitochondrial membrane (IMM) where it increases the efficiency of ATP regeneration. Confirm methods, effect sizes, and controls in the full PDF before citing the result as established.

Bibliographic record

Abstract-based editorial synthesis by Mitos. Not peer review.