title: Reconstructing the mitochondrial protein import machinery of Chlamydomonas reinhardtii.
abstract: In Chlamydomonas reinhardtii several nucleus-encoded proteins that participate in the mitochondrial oxidative phosphorylation are targeted to the organelle by unusually long mitochondrial targeting sequences. Here, we explored the components of the mitochondrial import machinery of the green alga. We mined the algal genome, searching for yeast and plant homologs, and reconstructed the mitochondrial import machinery. All the main translocation components were identified in Chlamydomonas as well as in Arabidopsis thaliana and in the recently sequenced moss Physcomitrella patens. Some of these components appear to be duplicated, as is the case of Tim22. In contrast, several yeast components that have relatively large hydrophilic regions exposed to the cytosol or to the intermembrane space seem to be absent in land plants and green algae. If present at all, these components of plants and algae may differ significantly from their yeast counterparts. We propose that long mitochondrial targeting sequences in some Chlamydomonas mitochondrial protein precursors are involved in preventing the aggregation of the hydrophobic proteins they carry.
authors.affiliation: Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, DF 04510, Mexico.
authors.forename: Francisco
authors.initials: F
authors.lastname: Figueroa-Martínez
authors.forename: Soledad
authors.initials: S
authors.lastname: Funes
authors.forename: Lars-Gunnar
authors.initials: LG
authors.lastname: Franzén
authors.forename: Diego
authors.initials: D
authors.lastname: González-Halphen
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000235:genetics; D019068:Bryopsida / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000235:genetics*; D019295:Computational Biology; D023281:Genomics; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D021381:Protein Transport / Q000235:genetics; D013045:Species Specificity
chemical_list: D002352:Carrier Proteins; D033681:Mitochondrial Membrane Transport Proteins