The transcriptional regulation of mitochondrial oxidative phosphorylation gene expression is poorly understood. In a recently published study, Gabriela Poliacikova, Marine Barthez and others from the IBDM, have shown that the transcription factor M1BP transcriptionally regulates the expression of genes encoding critical components for OXPHOS complex assembly and integrity. In the absence of M1BP function, the quantity of assembled mitochondrial respiratory complexes is reduced and OXPHOS proteins aggregate in the mitochondrial matrix, triggering a strong protein quality control response.