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Relationship between acyl-lipid and sterol metabolisms in diatoms.
Biochimie ( IF 3.9 ) Pub Date : 2019-07-07 , DOI: 10.1016/j.biochi.2019.07.005 Eric Maréchal 1 , Josselin Lupette 2
Biochimie ( IF 3.9 ) Pub Date : 2019-07-07 , DOI: 10.1016/j.biochi.2019.07.005 Eric Maréchal 1 , Josselin Lupette 2
Affiliation
Diatoms are a phylum of unicellular photosynthetic eukaryotes living in oceans and fresh waters, characterized by the complexity of their plastid, resulting from a secondary endosymbiosis event. In the model diatom Phaeodactylum tricornutum, fatty acids (FAs) are synthesized from acetyl-CoA in the stroma of the plastid, producing palmitic acid. FAs are elongated and desaturated to form very-long chain polyunsaturated fatty acids (VLC-PUFAs) in domains of the endomembrane system that need to be identified. Synthesis of VLC-PUFAs is coupled with their import to the core of the plastid via the so-called "omega" pathway. The biosynthesis of sterols in diatoms is likely to be localized in the endoplasmic reticulum as well as using precursors deriving from the mevalonate pathway, using acetyl-CoA as initial substrate. These metabolic modules can be characterized functionally by genetic analyzes or chemical treatments with appropriate inhibitors. Some 'metabolic modules' are characterized by a very low level of metabolic intermediates. Since some chemical treatments or genetic perturbation of lipid metabolism induce the accumulation of these intermediates, channeling processes are possibly involved, suggesting that protein-protein interactions might occur between enzymes within large size complexes or metabolons. At the junction of these modules, metabolic intermediates might therefore play dramatic roles in directing carbon fluxes from one direction to another. Here, acetyl-CoA seems determinant in the balance between TAGs and sterols. Future lines of research and potential utilization for biotechnological applications are discussed.
中文翻译:
硅藻的酰基脂质与固醇代谢之间的关系。
硅藻是生活在海洋和淡水中的单细胞光合作用真核生物的门,其特征是由于二次内共生事件而导致的质体的复杂性。在模型硅藻三角藻(Phaeodactylum tricornutum)中,由质体基质中的乙酰辅酶A合成脂肪酸(FAs),生成棕榈酸。FAs被拉长并去饱和以在需要鉴定的内膜系统域中形成非常长的链多不饱和脂肪酸(VLC-PUFAs)。VLC-PUFA的合成与它们通过所谓的“ω”途径导入质体的核心相结合。硅藻中固醇的生物合成很可能位于内质网中,并且使用乙酰甲酰辅酶A作为起始底物,使用甲羟戊酸途径衍生的前体。这些代谢模块可以通过基因分析或用适当的抑制剂进行化学处理来在功能上进行表征。一些“代谢模块”的特征是代谢中间体的含量非常低。由于脂质代谢的某些化学处理或遗传扰动会诱导这些中间体的积累,因此可能涉及通道化过程,这表明大分子复合物或代谢产物内的酶之间可能发生蛋白质-蛋白质相互作用。因此,在这些模块的交界处,代谢中间体可能在将碳通量从一个方向引导到另一个方向方面发挥重要作用。在这里,乙酰辅酶A似乎决定TAG和固醇之间的平衡。讨论了未来的研究方向以及对生物技术应用的潜在利用。
更新日期:2019-11-18
中文翻译:
硅藻的酰基脂质与固醇代谢之间的关系。
硅藻是生活在海洋和淡水中的单细胞光合作用真核生物的门,其特征是由于二次内共生事件而导致的质体的复杂性。在模型硅藻三角藻(Phaeodactylum tricornutum)中,由质体基质中的乙酰辅酶A合成脂肪酸(FAs),生成棕榈酸。FAs被拉长并去饱和以在需要鉴定的内膜系统域中形成非常长的链多不饱和脂肪酸(VLC-PUFAs)。VLC-PUFA的合成与它们通过所谓的“ω”途径导入质体的核心相结合。硅藻中固醇的生物合成很可能位于内质网中,并且使用乙酰甲酰辅酶A作为起始底物,使用甲羟戊酸途径衍生的前体。这些代谢模块可以通过基因分析或用适当的抑制剂进行化学处理来在功能上进行表征。一些“代谢模块”的特征是代谢中间体的含量非常低。由于脂质代谢的某些化学处理或遗传扰动会诱导这些中间体的积累,因此可能涉及通道化过程,这表明大分子复合物或代谢产物内的酶之间可能发生蛋白质-蛋白质相互作用。因此,在这些模块的交界处,代谢中间体可能在将碳通量从一个方向引导到另一个方向方面发挥重要作用。在这里,乙酰辅酶A似乎决定TAG和固醇之间的平衡。讨论了未来的研究方向以及对生物技术应用的潜在利用。