title: Peroxisomes in parasitic protists.
abstract: Representatives of all major lineages of eukaryotes contain peroxisomes with similar morphology and mode of biogenesis, indicating a monophyletic origin of the organelles within the common ancestor of all eukaryotes. Peroxisomes originated from the endoplasmic reticulum, but despite a common origin and shared morphological features, peroxisomes from different organisms show a remarkable diversity of enzyme content and the metabolic processes present can vary dependent on nutritional or developmental conditions. A common characteristic and probable evolutionary driver for the origin of the organelle is an involvement in lipid metabolism, notably H2O2-dependent fatty-acid oxidation. Subsequent evolution of the organelle in different lineages involved multiple acquisitions of metabolic processes-often involving retargeting enzymes from other cell compartments-and losses. Information about peroxisomes in protists is still scarce, but available evidence, including new bioinformatics data reported here, indicate striking diversity amongst free-living and parasitic protists from different phylogenetic supergroups. Peroxisomes in only some protists show major involvement in H2O2-dependent metabolism, as in peroxisomes of mammalian, plant and fungal cells. Compartmentalization of glycolytic and gluconeogenic enzymes inside peroxisomes is characteristic of kinetoplastids and diplonemids, where the organelles are hence called glycosomes, whereas several other excavate parasites (Giardia, Trichomonas) have lost peroxisomes. Amongst alveolates and amoebozoans patterns of peroxisome loss are more complicated. Often, a link is apparent between the niches occupied by the parasitic protists, nutrient availability, and the absence of the organelles or their presence with a specific enzymatic content. In trypanosomatids, essentiality of peroxisomes may be considered for use in anti-parasite drug discovery.
authors.affiliation: Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain. Electronic address: tgabaldon@crg.eu.
authors.forename: Toni
authors.initials: T
authors.lastname: Gabaldón
authors.affiliation: Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, UK; Department of Biological Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK. Electronic address: M.Ginger@hud.ac.uk.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Ginger
authors.affiliation: Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, UK; Centre for Translational and Chemical Biology, School of Biological Sciences, University of Edinburgh, UK; Laboratorio de Enzimología de Parásitos, Departamento de Biología, Universidad de Los Andes, Mérida, Venezuela. Electronic address: paul.michels@ed.ac.uk.
authors.forename: Paul A M
authors.initials: PA
authors.lastname: Michels
mesh_terms: D000818:Animals; D005075:Biological Evolution; D004734:Energy Metabolism; D010084:Oxidation-Reduction; D010271:Parasites / Q000502:physiology*; D020675:Peroxisomes / Q000378:metabolism*
keywords: Evolution; Fatty-acid metabolism; Metabolic diversity; Peroxide metabolism; Peroxisome; Protist