Protease OMA1 modulates mitochondrial bioenergetics and ultrastructure through dynamic association with MICOS complex

Remodeling of mitochondrial ultrastructure is a process that is critical for organelle physiology and apoptosis. Although the key players in this process-mitochondrial contact site and cristae junction organizing system (MICOS) and Optic Atrophy 1 (OPA1)-have been characterized, the mechanisms behind its regulation remain incompletely defined. Here, we found that in addition to its role in mitochondrial division, metallopeptidase OMA1 is required for the maintenance of intermembrane connectivity through dynamic association with MICOS. This association is independent of OPA1, mediated via the MICOS subunit MIC60, and is important for stability of MICOS and the intermembrane contacts. The OMA1-MI-COS relay is required for optimal bioenergetic output and apoptosis. Loss of OMA1 affects these activities; remarkably it can be alleviated by MICOS-emulating intermembrane bridge. Thus, OMA1-dependent ultrastructure support is required for mitochondrial architecture and bioenergetics under basal and stress conditions, suggesting a previously unrecognized role for OMA1 in mitochondrial physiology.

Automated summary

Remodeling of mitochondrial ultrastructure is critical for organelle physiology and apoptosis. OMA1, in addition to its role in mitochondrial division, is also required for maintaining intermembrane connectivity by dynamically associating with MICOS. This OMA1-MICOS relay is crucial for optimal bioenergetic output and cell apoptosis. Loss of OMA1 affects these functions but can be alleviated by a MICOS-emulating intermembrane bridge, highlighting OMA1's essential role in mitochondrial physiology.