Imoto Yuuta, Abe Yuichi, Okumoto Kanji, Honsho Masanori, Kuroiwa Haruko, Kuroiwa Tsuneyoshi, Fujiki Yukio
Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Department of Biology, Faculty of Sciences, Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395, Japan.
J Cell Sci. 2017 Mar 1;130(5):853-867. doi: 10.1242/jcs.199182. Epub 2017 Jan 23.
Organelle division is executed through contraction of a ring-shaped supramolecular dividing machinery. A core component of the machinery is the dynamin-based ring conserved during the division of mitochondrion, plastid and peroxisome. Here, using isolated peroxisome-dividing (POD) machinery from a unicellular red algae, , we identified a dynamin-based ring organizing center (DOC) that acts as an initiation point for formation of the dynamin-based ring. contains a single peroxisome, the division of which can be highly synchronized by light-dark stimulation; thus, intact POD machinery can be isolated in bulk. Dynamin-based ring homeostasis is maintained by the turnover of the GTP-bound form of the dynamin-related protein Dnm1 between the cytosol and division machinery via the DOC. A single DOC is formed on the POD machinery with a diameter of 500-700 nm, and the dynamin-based ring is unidirectionally elongated from the DOC in a manner that is dependent on GTP concentration. During the later step of membrane fission, the second DOC is formed and constructs the double dynamin-based ring to make the machinery thicker. These findings provide new insights to define fundamental mechanisms underlying the dynamin-based membrane fission in eukaryotic cells.
细胞器分裂是通过一种环形超分子分裂机制的收缩来执行的。该机制的一个核心组件是在线粒体、质体和过氧化物酶体分裂过程中保守的基于发动蛋白的环。在这里，我们使用从单细胞红藻中分离出的过氧化物酶体分裂（POD）机制，鉴定出一个基于发动蛋白的环组织中心（DOC），它作为基于发动蛋白的环形成的起始点。该红藻含有单个过氧化物酶体，其分裂可通过明暗刺激高度同步；因此，可以大量分离完整的POD机制。基于发动蛋白的环稳态通过发动蛋白相关蛋白Dnm1的GTP结合形式在细胞质和分裂机制之间经由DOC的周转来维持。在POD机制上形成一个直径为500 - 700纳米的单个DOC，基于发动蛋白的环以依赖于GTP浓度的方式从DOC单向延伸。在膜裂变的后期步骤中，形成第二个DOC并构建双基于发动蛋白的环以使机制变厚。这些发现为确定真核细胞中基于发动蛋白的膜裂变的基本机制提供了新的见解。
