title: Sterol metabolism in the filasterean Capsaspora owczarzaki has features that resemble both fungi and animals.
abstract: Sterols are essential for several physiological processes in most eukaryotes. Sterols regulate membrane homeostasis and participate in different signalling pathways not only as precursors of steroid hormones and vitamins, but also through its role in the formation of lipid rafts. Two major types of sterols, cholesterol and ergosterol, have been described so far in the opisthokonts, the clade that comprise animals, fungi and their unicellular relatives. Cholesterol predominates in derived bilaterians, whereas ergosterol is what generally defines fungi. We here characterize, by a combination of bioinformatic and biochemical analyses, the sterol metabolism in the filasterean Capsaspora owczarzaki, a close unicellular relative of animals that is becoming a model organism. We found that C. owczarzaki sterol metabolism combines enzymatic activities that are usually considered either characteristic of fungi or exclusive to metazoans. Moreover, we observe a differential transcriptional regulation of this metabolism across its life cycle. Thus, C. owczarzaki alternates between synthesizing 7-dehydrocholesterol de novo, which happens at the cystic stage, and the partial conversion-via a novel pathway-of incorporated cholesterol into ergosterol, the characteristic fungal sterol, in the filopodial and aggregative stages.
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario (IBR) CONICET and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda s/n, Rosario S2000FHQ, Argentina Institut de Biologia Evolutiva, CSIC-Universitat Pompeu Fabra, Passeig Marítim de la Barceloneta 37-49, Barcelona 08003, Catalonia, Spain najle@ibr-conicet.gov.ar.
authors.forename: Sebastián R
authors.identifier: 0000-0002-0654-9147
authors.initials: SR
authors.lastname: Najle
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario (IBR) CONICET and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda s/n, Rosario S2000FHQ, Argentina.
authors.forename: María Celeste
authors.initials: MC
authors.lastname: Molina
authors.affiliation: Institut de Biologia Evolutiva, CSIC-Universitat Pompeu Fabra, Passeig Marítim de la Barceloneta 37-49, Barcelona 08003, Catalonia, Spain Departament de Genètica, Universitat de Barcelona, Av. Diagonal, 645, Barcelona 08028, Catalonia, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 23, Barcelona 08010, Catalonia, Spain.
authors.forename: Iñaki
authors.initials: I
authors.lastname: Ruiz-Trillo
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario (IBR) CONICET and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda s/n, Rosario S2000FHQ, Argentina uttaro@ibr-conicet.gov.ar.
authors.forename: Antonio D
authors.initials: AD
authors.lastname: Uttaro
mesh_terms: D000818:Animals; D002784:Cholesterol / Q000378:metabolism; D004875:Ergosterol / Q000378:metabolism; D005658:Fungi / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D008018:Life Cycle Stages; D050298:Mesomycetozoea / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D010802:Phylogeny; D013261:Sterols / Q000378:metabolism*
chemical_list: D013261:Sterols; D002784:Cholesterol; D004875:Ergosterol
keywords: Capsaspora; cholesterol; ergosterol; opisthokonts; sterol metabolism; transcriptional regulation