Src-mediated PHB2 phosphorylation disrupts mitochondrial cristae through cardiolipin dissociation in hepatocellular...

Hepatocellular carcinoma (HCC) displays mitochondrial dysfunction characterized by disrupted redox homeostasis and cristae disorganization, yet the underlying molecular mechanisms are unclear. We reveal that Src kinase phosphorylates prohibitin 2 (PHB2) at tyrosines Y34 and Y77 under oxidative stress, disrupting its interaction with cardiolipin and triggering PHB1/2 complex disassembly. This event activates the mitochondrial protease OMA1, promoting excessive cleavage of the cristae-shaping protein OPA1, leading to severe cristae remodeling. Consequent impairment of electron transport chain supercomplexes decreases NAD+/NADH ratio and complex I/II activities, creating conditions that promote enhanced electron leakage and oxidative stress. This mitochondrial dysfunction drives a metabolic shift from oxidative phosphorylation toward glycolysis, promoting tumor growth in xenograft models. Phosphomimetic PHB2 mutants (Y34E/Y77E) exacerbate these effects, whereas phosphorylation-resistant mutants (Y34F/Y77F) restore cristae integrity, normalize redox balance, and suppress tumor progression. Our findings establish Src-mediated PHB2 phosphorylation as a redox-sensitive molecular switch that drives HCC metabolic reprogramming by disrupting the PHB2-cardiolipin cristae axis. This phosphorylation event represents a targetable vulnerability for this malignancy with limited treatment options.