TOM9.2 Is a Calmodulin-Binding Protein Critical for TOM Complex Assembly but Not for Mitochondrial Protein Import in Arabidopsis thaliana.

The translocon on the outer membrane of mitochondria (TOM) facilitates the import of nuclear-encoded proteins. The principal machinery of mitochondrial protein transport seems conserved in eukaryotes; however, divergence in the composition and structure of TOM components has been observed between mammals, yeast, and plants. TOM9, the plant homolog of yeast Tom22, is significantly smaller due to a truncation in the cytosolic receptor domain, and its precise function is not understood.