Cloning and characterization of a 35-kDa mouse mitochondrial outer membrane protein MOM35 with high homology to Tom40.

We have cloned a 35-kDa protein from a mouse cDNA library with a 25% overall amino acid identity to yTom40 and 27% identity to nTom40. This homolog toTom40 was named MOM35. It contains two possible start codons 36 amino acids apart from each other. Both the long and the short version of MOM35 can be imported in vitro into mouse mitochondria. The identified protein is imported into the outer mitochondrial membrane and comprises a trypsin-resistance pattern similar to that of nTom40. Tom40 of N. crassa, S. cerevisiae, and the protein identified herein contains a highly conserved region with possible physiological importance. Subsequent investigation has revealed that this region interacts specifically in vitro with preproteins proposed to be imported by a Tom40-dependent pathway.