The wide phylogenetic distribution of Oxa1-related proteins appears to reflect both the central role of assembling energy-transducing membrane complexes, and the range of roles in their assembly that Oxa1-related proteins can be adapted to. In different species, Oxa1 and its isoforms appear to assist in the assembly of several different substrate proteins. Recent work on the bacterial protein YidC strongly indicates that it is capable of functioning alone as a translocase for hydrophilic domains and an insertase for TM domains. Thus it is highly likely that the eukaryotic members of this family found in mitochondria and chloroplasts directly catalyze these reactions in a co- and/or post-translational way. It is presently unclear how Oxa1 recognizes its substrates and whether additional factors assist in this, beyond its direct interaction with mitochondrial ribosomes, demonstrated in S. cerevisiae. Given the apparent co-translational nature of in vivo Oxa1 dependent translocation of the Cox2 N-terminal domain, a detailed mechanistic study of this most critical Oxa1 function will need to await the development of a true in vitro translation system derived from the mitochondrial matrix and inner membrane. However, Oxa1 is also capable of assisting post-translational insertion and translocation in isolated mitochondria and Cox18 may post-translationally translocate both in vivo and in vitro its only known substrate, the Cox2 C-terminal domain. Thus, biochemical analysis of some of these functions in proteoliposomes may already be possible, taking advantage of the wide variety of mutant forms of S. cerevisiae Oxa1, to examine distinct activities of the protein. It is clear that interpretation of all genetic and biochemical data on Oxa1 and Cox18 will be far more robust when the structure of both proteins in the membrane will be determined.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Annotation Extension||Reference|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Assay||Construct||Conditions||Strain Background||Reference|