# Unconventional model organisms bend our view on mitochondrial cristae

## TL;DR

This review explores how mitochondria form cristae in diverse organisms, revealing conserved and unique mechanisms across eukaryotes.

## Contribution

The paper synthesizes crista formation mechanisms in non-traditional model organisms, offering a general model for mitochondrial structure.

## Key findings

- Cristae formation mechanisms are conserved in Euglenozoa, Alveolata, and Opisthokonta.
- ATP synthase, MICOS, and cardiolipin play key roles in crista curvature across species.
- Plasmodium falciparum exhibits de novo crista formation after an acristate life stage.

## Abstract

Cristae, convolutions of the inner mitochondrial membrane, provide an extended surface area for respiratory chain complexes and ATP synthases. Crista structure has been extensively researched in opisthokont model organisms, such as yeast and various animals; however, the vast majority of eukaryotic cristae diversity has been largely unexplored. Here, we provide a comprehensive overview of crista formation and maintenance in Euglenozoa and Alveolata, two highly divergent eukaryotic clades that include parasites of clinical and veterinary importance. Within these clades, cristae have been studied primarily in the kinetoplastid Trypanosoma brucei and the apicomplexan Toxoplasma gondii. We also discuss the apicomplexan Plasmodium falciparum, the deadliest human parasite and etiological agent of malaria, in which de novo formation of cristae occurs naturally following an apparently acristate life cycle stage. We compare findings from these divergent and disease-relevant organisms with those from more traditional model organisms, highlighting conserved and unique traits across the eukaryotic kingdom. In this Review, we focus on the roles of three key players in crista curvature – ATP synthase, the mitochondrial contact site and cristae organizing system (MICOS) and cardiolipin, a lipid specific to the inner mitochondrial membrane. By comparing distantly related organisms, we synthesize a broadly applicable model of the general principles of crista formation.

Summary: By comparing crista shaping and maintenance across Euglenozoa, Alveolata and Opisthokonta, this Review delineates evolutionarily conserved mechanisms underpinning a general model for crista formation.