Intermembrane space protein MIX23 regulates or stabilises the mitochondrial protein import machinery and is specifically up-regulated under stress conditions. It is critical for the efficient import of proteins into the mitochondrial matrix, particularly if the function of the translocase of the inner membrane 23 is compromised. MIX23, also known as Caffeine-induced death protein 2 (Cid2), is evolutionarily conserved and a homologue of the human protein CCDC58 [1].

1: The intermembrane space protein Mix23 is a novel stress-induced mitochondrial import factor. Zoller E, Laborenz J, Kramer L, Boos F, Raschle M, Alexander RT, Herrmann JM; J Biol Chem. 2020;295:14686-14697. PMID:32826315