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Origin and evolution of mitochondrial inner membrane composition.

Kailash Venkatraman1, Nicolas-Frédéric Lipp1, Itay Budin1

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Mitochondrial inner membrane folds (cristae) and specialized lipids co-evolved from bacterial ancestors during eukaryogenesis. This review explores the origins of mitochondrial membrane architecture and lipid synthesis machinery, proposing a model for their concurrent specialization.

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Area of Science:

  • Evolutionary biology
  • Cell biology
  • Biochemistry

Background:

  • Mitochondria possess unique membrane structures, including cristae, and specialized lipid compositions essential for eukaryotic cell function.
  • Mitochondria originated from an alphaproteobacterial endosymbiont, with key protein complexes like MICOS potentially having bacterial homologs involved in membrane formation.
  • The evolutionary origins of the machinery synthesizing mitochondrial phospholipids, crucial for inner membrane architecture, remain less explored.

Purpose of the Study:

  • To review the current understanding of mitochondrial membrane evolution.
  • To highlight distinctions between prokaryotic and eukaryotic mitochondrial proteins and lipids.
  • To propose a model for the co-evolution of the mitochondrial lipidome and inner membrane structure during eukaryogenesis.

Main Methods:

  • Phylogenetic analysis
  • Genomic and metagenomic data analysis
  • Comparative analysis of protein and lipid machinery between prokaryotes and eukaryotes

Main Results:

  • MICOS protein homologs are implicated in cristae-like membrane formation in alphaproteobacteria.
  • The machinery for synthesizing key mitochondrial phospholipids likely shares a bacterial ancestry.
  • Distinct evolutionary paths exist for prokaryotic and eukaryotic membrane-shaping proteins and lipids.

Conclusions:

  • Mitochondrial cristae and lipid composition evolved concurrently from bacterial precursors during eukaryogenesis.
  • Understanding the co-evolution of membrane components provides insights into the fundamental functions of eukaryotic mitochondria.
  • Interdisciplinary advancements are crucial for elucidating the complex evolutionary history of mitochondrial membranes.