Vedrenne Cécile, Giroud Christiane, Robinson Derrick R, Besteiro Sébastien, Bosc Christophe, Bringaud Frédéric, Baltz Théo
Laboratoire de Parasitologie Moléculaire, Université Victor Segalen de Bordeaux II, Unité Mixte Recherche-5016 Centre National de la Recherche Scientifique, 33076 Bordeaux, France.
Mol Biol Cell. 2002 Mar;13(3):1058-70. doi: 10.1091/mbc.01-06-0298.
The subpellicular microtubules of the trypanosome cytoskeleton are cross-linked to each other and the plasma membrane, creating a cage-like structure. We have isolated, from Trypanosoma brucei, two related low-molecular-weight cytoskeleton-associated proteins (15- and 17-kDa), called CAP15 and CAP17, which are differentially expressed during the life cycle. Immunolabeling shows a corset-like colocalization of both CAPs and tubulin. Western blot and electron microscope analyses show CAP15 and CAP17 labeling on detergent-extracted cytoskeletons. However, the localization of both proteins is restricted to the anterior, microtubule minus, and less dynamic half of the corset. CAP15 and CAP17 share properties of microtubule-associated proteins when expressed in heterologous cells (Chinese hamster ovary and HeLa), colocalization with their microtubules, induction of microtubule bundle formation, cold resistance, and insensitivity to nocodazole. When overexpressed in T. brucei, both CAP15 and CAP17 cover the whole subpellicular corset and induce morphological disorders, cell cycle-based abnormalities, and subsequent asymmetric cytokinesis.
锥虫细胞骨架的表膜下微管相互交联并与质膜相连，形成一种笼状结构。我们从布氏锥虫中分离出两种相关的低分子量细胞骨架相关蛋白（15 kDa和17 kDa），分别称为CAP15和CAP17，它们在生命周期中差异表达。免疫标记显示这两种CAP蛋白与微管蛋白呈束腰状共定位。蛋白质免疫印迹和电子显微镜分析表明，在去污剂提取的细胞骨架上有CAP15和CAP17的标记。然而，这两种蛋白质的定位仅限于束腰的前部、微管负端以及动态较弱的一半区域。当在异源细胞（中国仓鼠卵巢细胞和HeLa细胞）中表达时，CAP15和CAP17具有微管相关蛋白的特性，与微管共定位，诱导微管束形成，具有抗冷性且对诺考达唑不敏感。当在布氏锥虫中过表达时，CAP15和CAP17覆盖整个表膜下束腰，并诱导形态紊乱、基于细胞周期的异常以及随后的不对称胞质分裂。
