Cox17 Protein Is an Auxiliary Factor Involved in the Control of the Mitochondrial Contact Site and Cristae Organizing System

Background: MICOS is a recently identified complex that is important for maintaining the architecture of the mitochondrial inner membrane. Results: Cox17 interacts with the MICOS complex, and this interaction is promoted by copper ions. Conclusion: Cox17 regulates MICOS integrity. Significance: Learning the way in which MICOS is regulated provides important insights into processes that are responsible for mitochondrial form and function.
The mitochondrial contact site and cristae organizing system (MICOS) is a recently discovered protein complex that is crucial for establishing and maintaining the proper inner membrane architecture and contacts with the outer membrane of mitochondria. The ways in which the MICOS complex is assembled and its integrity is regulated remain elusive. Here, we report a direct link between Cox17, a protein involved in the assembly of cytochrome c oxidase, and the MICOS complex. Cox17 interacts with Mic60, thereby modulating MICOS complex integrity. This interaction does not involve Sco1, a partner of Cox17 in transferring copper ions to cytochrome c oxidase. However, the Cox17-MICOS interaction is regulated by copper ions. We propose that Cox17 is a newly identified factor involved in maintaining the architecture of the MICOS complex.