Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria - CSIC - SODERCAN, Santander, Spain.
Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Institut de Biologie Physico-Chimique, CNRS, Univ Paris Diderot, Sorbonne Paris Cité, PSL Research University, Paris, France.
Biochim Biophys Acta Biomembr. 2017 Jun;1859(6):1124-1132. doi: 10.1016/j.bbamem.2017.03.006. Epub 2017 Mar 9.
Mitochondria, chloroplasts and photosynthetic bacteria are characterized by the presence of complex and intricate membrane systems. In contrast, non-photosynthetic bacteria lack membrane structures within their cytoplasm. However, large scale over-production of some membrane proteins, such as the fumarate reductase, the mannitol permease MtlA, the glycerol acyl transferase PlsB, the chemotaxis receptor Tsr or the ATP synthase subunit b, can induce the proliferation of intra cellular membranes (ICMs) in the cytoplasm of Escherichia coli. These ICMs are particularly rich in cardiolipin (CL). Here, we have studied the effect of CL in the generation of these membranous structures. We have deleted the three genes (clsA, clsB and clsC) responsible of CL biosynthesis in E. coli and analysed the effect of these mutations by fluorescent and electron microscopy and by lipid mass spectrometry. We have found that CL is essential in the formation of non-lamellar structures in the cytoplasm of E. coli cells. These results could help to understand the structuration of membranes in E. coli and other membrane organelles, such as mitochondria and ER.
线粒体、叶绿体和光合细菌的特点是存在复杂而精细的膜系统。相比之下，非光合细菌的细胞质内缺乏膜结构。然而，一些膜蛋白的大规模过度表达，如延胡索酸还原酶、甘露醇通透酶 MtlA、甘油酰基转移酶 PlsB、趋化性受体 Tsr 或 ATP 合酶亚基 b，会诱导大肠杆菌细胞质中细胞内膜 (ICMs) 的增殖。这些 ICMs 富含心磷脂 (CL)。在这里，我们研究了 CL 对这些膜结构产生的影响。我们敲除了大肠杆菌中负责 CL 生物合成的三个基因 (clsA、clsB 和 clsC)，并通过荧光和电子显微镜以及脂质质谱分析了这些突变的影响。我们发现 CL 对于大肠杆菌细胞质中非层状结构的形成是必需的。这些结果有助于理解大肠杆菌和其他膜细胞器（如线粒体和内质网）的膜结构。
