biogenesis of the trypanosome endo-exocytotic organelle is cytoskeleton mediated生物起源的锥体虫endo-exocytotic细胞器是细胞骨架介导.pdfVIP

PLoS BIOLOGY Biogenesis of the Trypanosome Endo-Exocytotic Organelle Is Cytoskeleton Mediated ´ ¤ * Melanie Bonhivers, Sophie Nowacki , Nicolas Landrein, Derrick R. Robinson ´ ´ ´ Microbiologie Cellulaire et Moleculaire et Pathogenicite (MCMP), UMR-CNRS 5234, University Bordeaux 2, Bordeaux, Cedex France Trypanosoma brucei is a protozoan parasite that is used as a model organism to study such biological phenomena as gene expression, protein trafficking, and cytoskeletal biogenesis. In T. brucei, endocytosis and exocytosis occur exclusively through a sequestered organelle called the flagellar pocket (FP), an invagination of the pellicular membrane. The pocket is the sole site for specific receptors thus maintaining them inaccessible to components of the innate immune system of the mammalian host. The FP is also responsible for the sorting of protective parasite glycoproteins targeted to, or recycling from, the pellicular membrane, and for the removal of host antibodies from the cell surface. Here, we describe the first characterisation of a flagellar pocket cytoskeletal protein, BILBO1. BILBO1 functions to form a cytoskeleton framework upon which the FP is made and which is also required and essential for FP biogenesis and cell survival. Remarkably, RNA interference (RNAi)-mediated ablation of BILBO1 in insect procyclic-form parasites prevents FP biogenesis and induces vesicle accumulation, Golgi swelling, the aberrant repositioning of the new flagellum, and cell death. Cultured bloodstream-form parasites are also nonviable when subjected to