title: Assembly and maintenance of the flagellum attachment zone filament in Trypanosoma brucei.
abstract: Adhesion of motile flagella to the cell body in Trypanosoma brucei requires a filamentous cytoskeletal structure termed the flagellum attachment zone (FAZ). Despite its essentiality, the complete molecular composition of the FAZ filament and its roles in FAZ filament assembly remain poorly understood. By localization-based screening, we here identified a new FAZ protein, which we called FAZ2. Knockdown of FAZ2 disrupted the FAZ filament, destabilized multiple FAZ filament proteins and caused a cytokinesis defect. We also showed that FAZ2 depletion destabilized another new FAZ filament protein and several flagellum and cytoskeleton proteins. Furthermore, we identified CC2D and KMP11 as FAZ2 partners through affinity purification, and showed that they are each required for maintaining a stable complex. Finally, we demonstrated that FAZ filament proteins are incorporated into the FAZ filament from the proximal region, in contrast to the flagellum components, which are incorporated from the distal tip. In summary, we identified three new FAZ filament proteins and a FAZ filament protein complex, and our results suggest that assembly of the FAZ filament occurs at the proximal region and is essential to maintain the stability of FAZ filament proteins.
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, TX 77030, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, TX 77030, USA.
authors.forename: Huiqing
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Biological Sciences, National University of Singapore, 117543, Singapore.
authors.forename: Cynthia Y
authors.initials: CY
authors.lastname: He
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, TX 77030, USA Ziyin.Li@uth.tmc.edu.
authors.forename: Ziyin
authors.initials: Z
authors.lastname: Li
mesh_terms: D002460:Cell Line; D048749:Cytokinesis; D003598:Cytoskeletal Proteins / Q000378:metabolism; D015536:Down-Regulation; D015180:Electrophoresis, Gel, Two-Dimensional; D005407:Flagella / Q000378:metabolism*; D055550:Protein Stability; D015800:Protozoan Proteins / Q000378:metabolism; D034622:RNA Interference; D014346:Trypanosoma brucei brucei / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; D015800:Protozoan Proteins
keywords: Flagellum adhesion; Flagellum attachment zone; Trypanosoma brucei