The evolution of cardiolipin biosynthesis and maturation pathways and its implications for the evolution of eukaryotes

BMC Evolutionary Biology

Research Article

Jian-Fan Wen¹  Jin-Mei Feng²  Hai-Feng Tian² 

[1] State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan Province, China;State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan Province, China;Graduate School of the Chinese Academy of Sciences, 100039, Beijing, China;

关键词: Cardiolipin synthase;    Phylogenetic distribution;    Phylogenetic analysis;    Mitochondrial endosymbiosis;    Eukaryotic evolution;   

DOI  :  10.1186/1471-2148-12-32

 received in 2011-09-09, accepted in 2012-03-13,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundCardiolipin (CL) is an important component in mitochondrial inner and bacterial membranes. Its appearance in these two biomembranes has been considered as evidence of the endosymbiotic origin of mitochondria. But CL was reported to be synthesized through two distinct enzymes--CLS_cap and CLS_pld in eukaryotes and bacteria. Therefore, how the CL biosynthesis pathway evolved is an interesting question.ResultsPhylogenetic distribution investigation of CL synthase (CLS) showed: most bacteria have CLS_pld pathway, but in partial bacteria including proteobacteria and actinobacteria CLS_cap pathway has already appeared; in eukaryotes, Supergroup Opisthokonta and Archaeplastida, and Subgroup Stramenopiles, which all contain multicellular organisms, possess CLS_cap pathway, while Supergroup Amoebozoa and Excavata and Subgroup Alveolata, which all consist exclusively of unicellular eukaryotes, bear CLS_pld pathway; amitochondriate protists in any supergroups have neither. Phylogenetic analysis indicated the CLS_cap in eukaryotes have the closest relationship with those of alpha proteobacteria, while the CLS_pld in eukaryotes share a common ancestor but have no close correlation with those of any particular bacteria.ConclusionsThe first eukaryote common ancestor (FECA) inherited the CLS_pld from its bacterial ancestor (e. g. the bacterial partner according to any of the hypotheses about eukaryote evolution); later, when the FECA evolved into the last eukaryote common ancestor (LECA), the endosymbiotic mitochondria (alpha proteobacteria) brought in CLS_cap, and then in some LECA individuals the CLS_cap substituted the CLS_pld, and these LECAs would evolve into the protist lineages from which multicellular eukaryotes could arise, while in the other LECAs the CLS_pld was retained and the CLS_cap was lost, and these LECAs would evolve into the protist lineages possessing CLS_pld. Besides, our work indicated CL maturation pathway arose after the emergence of eukaryotes probably through mechanisms such as duplication of other genes, and gene duplication and loss occurred frequently at different lineage levels, increasing the pathway diversity probably to fit the complicated cellular process in various cells. Our work also implies the classification putting Stramenopiles and Alveolata together to form Chromalveolata may be unreasonable; the absence of CL synthesis and maturation pathways in amitochondriate protists is most probably due to secondary loss.

【 授权许可】

Unknown   
© Tian et al; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.