title: Complex evolution of two types of cardiolipin synthase in the eukaryotic lineage stramenopiles.
abstract: The phospholipid cardiolipin is indispensable for eukaryotes to activate mitochondria, and it was previously reported that two phylogenetically distinct types of enzyme synthesizing cardiolipin, one with two phospholipase D domains (CLS_pld) and the other with a CDP-alcohol phosphatidyltransferase domain (CLS_cap), are patchily and complementarily distributed at higher taxonomic (e.g., supergroup) levels of eukaryotes. Stramenopiles, one of the major eukaryotic clades, were considered to exclusively possess CLS_cap. However, through our present surveys with genome or transcriptome data from a broad range of stramenopile taxa, species with both CLS_cap and CLS_pld and species with only CLS_pld or CLS_cap were discovered among this group. Because these homologues of CLS_cap and CLS_pld retrieved from stramenopiles were likely inherited from the last eukaryotic common ancestor, it is reasonable to assume that a common ancestor of all stramenopiles harbored both CLS_cap and CLS_pld. Furthermore, based on the robust organismal phylogeny of stramenopiles unveiled with large-scale phylogenetic analyses, the earliest diverging lineage of stramenopiles (including bicosoecids, placidids, etc.) was found to comprise species with both CLS_cap and CLS_pld along with species with only either CLS_cap or CLS_pld. These findings suggest that a common ancestor of the most basal stramenopile lineage retained these two vertically inherited enzymes and that differential losses of either CLS_cap or CLS_pld occurred in this lineage. On the other hand, in the other stramenopile lineage composed of Ochrophyta, Pseudofungi, and Labyrinthulomycetes (to the exclusion of the most basal lineage), only CLS_cap was found, and therefore a common ancestor of these three groups likely lost CLS_pld. Based on our findings, the evolution of CLS_cap/CLS_pld in stramenopiles appears to be more complex than previously thought.
authors.affiliation: Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Minato-ku, Tokyo, Japan; Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan.
authors.forename: Fumiya
authors.initials: F
authors.lastname: Noguchi
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
authors.forename: Goro
authors.initials: G
authors.lastname: Tanifuji
authors.affiliation: Department of Biological Sciences, Mississippi State University, MS, USA; Institute for Genomics, Biocomputing & Biotechnology, Mississippi State University, MS, USA.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Brown
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Fujikura
authors.affiliation: Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Minato-ku, Tokyo, Japan; Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan. Electronic address: takishitak@jamstec.go.jp.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Takishita
mesh_terms: D018076:DNA, Complementary / Q000737:chemistry / Q000378:metabolism; D019143:Evolution, Molecular; D008565:Membrane Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria; D010802:Phylogeny; D012313:RNA / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D058009:Stramenopiles / Q000201:enzymology*; D017855:Transferases (Other Substituted Phosphate Groups) / Q000145:classification / Q000235:genetics / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D008565:Membrane Proteins; D012313:RNA; D017855:Transferases (Other Substituted Phosphate Groups); C100091:cardiolipin synthetase
keywords: Cardiolipin synthase; Differential gene loss; Eukaryotes; Phylogenomics; Stramenopiles