A 60-kDa Cytoskeletal Protein from Trypanosoma brucei brucei Can Interact with Membranes and with Microtubules

The cytoskeleton of eukaryotic cells is a major determinant of cellular architecture and of many cellular functions. In addition to or in place of the transcellular cytoskeleton, many eukaryotic cells also contain membrane-associated cytoskeletal structures (membrane skeletons), which are important for cellular structure and function. The membrane skeleton of the parasitic hemoflagellate Trypanosoma brucei consists of a dense array of singlet microtubules (subpellicular microtubules), which are tightly associated to the overlying cell membrane. This study reports the identification of a microtubule-associated protein from Trypanosoma brucei that constitutes a component of the link between this microtubular array and the cell membrane. The protein can bind in vitro both to microtubules and to membrane vesicles or liposomes. Furthermore, it can crosslink microtubules and membrane vesicles, suggesting that it exerts a similar function in the membrane skeleton.