Levels of human Fis1 at the mitochondrial outer membrane regulate mitochondrial morphology
Levels of human Fis1 at the mitochondrial outer membrane regulate mitochondrial morphology
复制标题
DOI：
10.1242/jcs.01058
复制
发表时间：
2004-03-01
影响因子：
4
通讯作者：
Ryan, MT
中科院分区：
文献类型：
--
作者：
Stojanovski, D;Koutsopoulos, OS;Ryan, MT
线粒体经历平衡的裂变和融合事件，使它们能够在细胞内适当地联网。在酵母中，已经确定了三个因素，协调线粒体的裂变事件。外膜Fis1p作为外膜受体募集发动蛋白成员Dnm1p和含WD 40重复序列的蛋白Mdv1p。在哺乳动物中，Dnm1p对应物Drp1已被表征，但其他组分尚未被表征。在这里，我们报告的人Fis1（hFis1）的特性。hFis1通过C-末端跨膜结构域插入线粒体外膜中，该跨膜结构域与短的碱性片段一起沿着对其靶向是必需的。虽然hFis1的表达不能补充缺乏Fis1p的酵母细胞的表型，但hFis1在组织培养细胞中的过表达仍然引起线粒体片段化和聚集。这种聚集可以通过表达显性负性Drp1突变体（Drp1（K38A））来抑制。使用RNA干扰在COS-7细胞中敲低hFis1导致线粒体形态缺陷，线粒体小管长度显著延长。这些结果表明，在线粒体表面的hFis1的水平影响线粒体分裂事件，因此在细胞内的整体线粒体形态。
Mitochondria undergo balanced fission and fusion events that enable their appropriate networking within the cell. In yeast, three factors have been identified that co-ordinate fission events at the mitochondrial. outer membrane. Fis1p acts as the outer membrane receptor for recruitment of the dynamin member, Dnm1p and the WD40-repeat-containing protein Mdv1p. In mammals, the Dnm1p counterpart Drp1 has been characterized, but other components have not. Here, we report the characterization of human Fis1 (hFis1). hFis1 is inserted into the mitochondrial outer membrane via a C-terminal transmembrane domain that, along with a short basic segment, is essential for its targeting. Although expression of hFis1 does not complement the phenotype of yeast cells lacking Fis1p, overexpression of hFis1 in tissue culture cells nevertheless causes mitochondrial fragmentation and aggregation. This aggregation could be suppressed by expressing a dominant-negative Drp1 mutant (Drp1(K38A)). Knockdown of hFis1 in COS-7 cells using RNA interference results in mitochondrial morphology defects with notable extensions in the length of mitochondrial tubules. These results indicate that the levels of hFis1 at the mitochondrial surface influences mitochondrial fission events and hence overall mitochondrial morphology within the cell.