The mystery of mitochondrial plasticity: TMBIM5 integrates metabolic state and proteostasis.

How cellular cues alter the mitochondrial proteome and impact the composition of mitochondrial proteins remains poorly understood. In this issue of The EMBO Journal, Patron et al (2022) identify TMBIM5 as an important link between calcium homeostasis, proton motive force, and mitochondrial proteolysis, by which the organelle can modify its protein composition. The results may be crucial for our understanding of the plasticity of mitochondria.