University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33000 Bordeaux, France.
Department of Genetics, Bldg. NW1, University of Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany.
Parasite. 2022;29:14. doi: 10.1051/parasite/2022015. Epub 2022 Mar 9.
The flagellar pocket (FP) of the pathogen Trypanosoma brucei is an important single copy structure that is formed by the invagination of the pellicular membrane. It is the unique site of endo- and exocytosis and is required for parasite pathogenicity. The FP consists of distinct structural sub-domains with the least explored being the flagellar pocket collar (FPC). TbBILBO1 is the first-described FPC protein of Trypanosoma brucei. It is essential for parasite survival, FP and FPC biogenesis. In this work, we characterize TbKINX1B, a novel TbBILBO1 partner. We demonstrate that TbKINX1B is located on the basal bodies, the microtubule quartet (a set of four microtubules) and the FPC in T. brucei. Down-regulation of TbKINX1B by RNA interference in bloodstream forms is lethal, inducing an overall disturbance in the endomembrane network. In procyclic forms, the RNAi knockdown of TbKINX1B leads to a minor phenotype with a small number of cells displaying epimastigote-like morphologies, with a misplaced kinetoplast. Our results characterize TbKINX1B as the first putative kinesin to be localized both at the basal bodies and the FPC with a potential role in transporting cargo along with the microtubule quartet.
虫体的鞭毛窝（FP）是一种重要的单拷贝结构，由质膜内陷形成。它是内吞作用和外排作用的唯一部位，也是寄生虫致病所必需的。FP 由不同的结构亚域组成，其中研究最少的是鞭毛窝环（FPC）。TbBILBO1 是布氏锥虫中第一个描述的 FPC 蛋白。它对寄生虫的生存、FP 和 FPC 的发生是必不可少的。在这项工作中，我们对 TbKINX1B 进行了表征，这是一种新的 TbBILBO1 伴侣。我们证明 TbKINX1B 位于基体、微管四联体（一组四个微管）和 T. brucei 的 FPC 上。在血腔形式中通过 RNA 干扰下调 TbKINX1B 是致命的，导致内质网网络的整体紊乱。在前鞭毛体形式中，TbKINX1B 的 RNAi 敲低导致少数细胞表现出类似于动基体的形态，动基体位置不当的轻微表型。我们的结果将 TbKINX1B 表征为第一个被定位在基体和 FPC 的假定驱动蛋白，它可能在沿着微管四联体运输货物方面发挥作用。
