Mitochondrial Lipids in Cellular Adaptation.

Mitochondria serve as central hubs of cellular bioenergetics and signaling, yet the dynamic role of their lipid composition in cellular adaptation remains underappreciated. Unlike most organelles, mitochondria possess a unique dual-bilayer membrane architecture shaped by lipid transport and de novo synthesis. The mitochondrial lipidome, dominated by phosphatidylcholine, phosphatidylethanolamine, and the signature phospholipid cardiolipin, influences cristae organization, oxidative phosphorylation capacity, and metabolite transport, collectively determining whether mitochondria undergo stabilization, remodeling, or degradation. In this review, we explore how mitochondrial lipid dynamics sustain organelle-wide homeostasis while coordinating cellular adaptation across multiple temporal scales and how failure of lipid homeostasis drives rare monogenic disorders and complex pathologies. We propose that environmental shifts transiently disrupt the balance between phospholipid biosynthesis and utilization, generating changes in mitochondrial lipid homeostasis that promote cellular adaptation through complementary biophysical and biochemical signaling mechanisms. Specifically, membrane lipid remodeling rapidly alters membrane biophysical properties to regulate membrane protein activity, whereas bioactive phospholipid intermediates and side-products support long-term adaptive reprogramming. Mitochondrial lipids therefore function not merely as passive structural components but as active regulatory nodes that drive cellular plasticity, positioning lipid dynamics at the nexus of metabolic adaptation and human disease.