Translocase Of Inner Mitochondrial Membrane 23 (TIMM23)

Sequence analysis predicted that the 209-amino acid TIMM23 protein shares 22% amino acid identity with yeast Tim23 and contains 4 hydrophobic membrane-spanning segments that conserve the N-out/C-out topology of yeast TIMs. TIMM23 also has a 74-amino acid N-terminal hydrophilic segment that is dissimilar to the N-terminal hydrophilic domain of yeast Tim23. Northern blot analysis detected a 2.9-kb TIMM23 transcript that was highly expressed in heart and skeletal muscle, intermediately expressed in brain, and weakly expressed in pancreas, placenta, kidney, and liver. Western blot analysis showed that TIMM23 colocalizes with the inner membrane fraction of mitochondria as a 23-kD protein. TIMM23 is organized into 2 distinct 110-kD complexes in the inner membrane, one containing TIMM17A and the other containing TIMM17B