Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland.
Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland.
J Cell Sci. 2021 Mar 8;134(5):jcs254300. doi: 10.1242/jcs.254300.
Proper mitochondrial genome inheritance is important for eukaryotic cell survival. , a protozoan parasite, contains a singular mitochondrial genome, the kinetoplast (k)DNA. The kDNA is anchored to the basal body via the tripartite attachment complex (TAC) to ensure proper segregation. Several components of the TAC have been described; however, the connection of the TAC to the kDNA remains elusive. Here, we characterize the TAC-associated protein TAP110. We find that both depletion and overexpression of TAP110 leads to a delay in the separation of the replicated kDNA networks. Proteome analysis after TAP110 overexpression identified several kDNA-associated proteins that changed in abundance, including a TEX-like protein that dually localizes to the nucleus and the kDNA, potentially linking replication and segregation in the two compartments. The assembly of TAP110 into the TAC region seems to require the TAC but not the kDNA itself; however, once TAP110 has been assembled, it also interacts with the kDNA. Finally, we use ultrastructure expansion microscopy in trypanosomes for the first time, and reveal the precise position of TAP110 between TAC102 and the kDNA, showcasing the potential of this approach.This article has an associated First Person interview with the first author of the paper.
正确的线粒体基因组遗传对于真核细胞的存活至关重要。一种原生动物寄生虫，含有一个单一的线粒体基因组，即动基体（k）DNA。kDNA 通过三联体附着复合物（TAC）与基体相连，以确保正确的分离。TAC 的几个组成部分已经被描述过；然而，TAC 与 kDNA 的连接仍然难以捉摸。在这里，我们描述了 TAC 相关蛋白 TAP110。我们发现，TAP110 的耗竭和过表达都会导致复制的 kDNA 网络分离的延迟。TAP110 过表达后的蛋白质组分析鉴定出几种 kDNA 相关蛋白的丰度发生了变化，包括一种 TEX 样蛋白，它双重定位于核和 kDNA，可能将两个隔室中的复制和分离联系起来。TAP110 组装到 TAC 区域似乎需要 TAC，但不需要 kDNA 本身；然而，一旦 TAP110 被组装，它也与 kDNA 相互作用。最后，我们首次在锥虫中使用超结构扩展显微镜，并揭示了 TAP110 在 TAC102 和 kDNA 之间的确切位置，展示了这种方法的潜力。本文有一篇与论文第一作者的相关第一人称采访。
