title: Screening and discovery of lineage-specific mitosomal membrane proteins in Entamoeba histolytica.
abstract: Entamoeba histolytica, an anaerobic intestinal parasite causing dysentery and extra-intestinal abscesses in humans, possesses highly reduced and divergent mitochondrion-related organelles (MROs) called mitosomes. This organelle lacks many features associated with canonical aerobic mitochondria and even other MROs such as hydrogenosomes. The Entamoeba mitosome has been found to have a compartmentalized sulfate activation pathway, which was recently implicated to have a role in amebic stage conversion. It also features a unique shuttle system via Tom60, which delivers proteins from the cytosol to the mitosome. In addition, only Entamoeba mitosomes possess a novel subclass of β-barrel outer membrane protein called MBOMP30. With the discoveries of such unique features of mitosomes of Entamoeba, there still remain a number of significant unanswered issues pertaining to this organelle. Particularly, the present understanding of the inner mitosomal membrane of Entamoeba is extremely limited. So far, only a few homologs for transporters of various substrates have been confirmed, while the components of the protein translocation complexes appear to be absent or are yet to be discovered. Employing a similar strategy as in our previous work, we collaborated to screen and discover mitosomal membrane proteins. Using a specialized prediction pipeline, we searched for proteins possessing α-helical transmembrane domains, which are unique to E. histolytica mitosomes. From the prediction algorithm, 25 proteins emerged as candidates, two of which were initially observed to be localized to the mitosomes. Further screening and analysis of the predicted proteins may provide clues to answer key questions on mitosomal evolution, biogenesis, dynamics, and biochemical processes.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
authors.forename: Herbert J
authors.initials: HJ
authors.lastname: Santos
authors.affiliation: Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Imai
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hanadate
authors.affiliation: Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fukasawa
authors.affiliation: Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Oda
authors.affiliation: Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan; Division of Molecular and Cellular Immunoscience, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga, Japan.
authors.forename: Fumika
authors.initials: F
authors.lastname: Mi-Ichi
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan. Electronic address: nozaki@nih.go.jp.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Nozaki
mesh_terms: D000595:Amino Acid Sequence; D005075:Biological Evolution; D066264:Datasets as Topic; D004748:Entamoeba histolytica / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000737:chemistry / Q000378:metabolism*; D021381:Protein Transport; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D015800:Protozoan Proteins
keywords: Entamoeba histolytica; Mitosomal membrane protein; Mitosome; Transmembrane domain