Novel TPR-containing subunit of TOM complex functions as cytosolic receptor for Entamoeba mitosomal transport.
Under anaerobic environments, the mitochondria have undergone remarkable reduction and transformation into highly reduced structures, referred as mitochondrion-related organelles (MROs), which include mitosomes and hydrogenosomes. In agreement with the concept of reductive evolution, mitosomes of Entamoeba histolytica lack most of the components of the TOM (translocase of the outer mitochondrial membrane) complex, which is required for the targeting and membrane translocation of preproteins into the canonical aerobic mitochondria. Here we showed, in E. histolytica mitosomes, the presence of a 600-kDa TOM complex composed of Tom40, a conserved pore-forming subunit, and Tom60, a novel lineage-specific receptor protein. Tom60, containing multiple tetratricopeptide repeats, is localized to the mitosomal outer membrane and the cytosol, and serves as a receptor of both mitosomal matrix and membrane preproteins. Our data indicate that Entamoeba has invented a novel lineage-specific shuttle receptor of the TOM complex as a consequence of adaptation to an anaerobic environment.
Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan.
Takashi
T
Makiuchi
Fumika
F
Mi-ichi
Kumiko
K
Nakada-Tsukui
Tomoyoshi
T
Nozaki
D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004747:Entamoeba / Q000378:metabolism*; D020868:Gene Silencing; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D010641:Phenotype; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D021122:Protein Subunits; D015800:Protozoan Proteins