Vol. 13, Issue 3, 1058-1070, March 2002

Two Related Subpellicular Cytoskeleton-associated Proteins in Trypanosoma brucei Stabilize Microtubules

Cécile Vedrenne,^* Christiane Giroud,^* Derrick R. Robinson, Sébastien Besteiro,^* Christophe Bosc,^§ Frédéric Bringaud,^* and Théo Baltz^*

 ^*Laboratoire de Parasitologie Moléculaire, Université Victor Segalen de Bordeaux II, Unité Mixte Recherche-5016 Centre National de la Recherche Scientifique, 33076 Bordeaux, France;  University of Manchester, Manchester, M13 9PT England; and  ^§Commissariat à l'Energie Atomique, Laboratoire du Cytosquelette, Institut National de la Santé et de la Recherche Médicale Unité 366, 38054 Grenoble, France

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.