tRNA import across the mitochondrial outer membrane of African trypanosomes requires the ATOM complex

African trypanosomes belong to the eukaryotic supergroup of the Excavata and are considered to be among the earliest diverging eukaroytes that have bona fide mitochondria capable of oxidative phosphorylation. The mitochondrial genome of these unicellular parasites does not encode for any tRNA genes, thus all tRNAs used in mitochondrial translation have to be imported from the cytosol across the two mitochondrial membranes. The mitochondrial outer membrane (MOM) of Trypanosomes lacks a canonical TOM-complex and proteins are imported across the MOM using the ATOM (archaic translocase of the outer mitochondrial membrane) complex. Interestingly, the pore-forming component (ATOM40) is related to both, eukaryotic Tom40 and to members of the bacterial Omp85 protein family. Combining different in vivo and in vitro strategies we were able to show that the ATOM complex is also required to translocate tRNA across the MOM. Our data further suggest that tRNA import is independent of protein import.