Cytoplasmic preassembly of the flagellar outer dynein arm complex in Trypanosoma brucei

• Published in: Molecular biology of the cell 2024-09, Vol.35 (9), p.br16
• Main Authors: Balasubramaniam, Karthika, He, Tingting, Chen, Helen, Lin, Zhewang, He, Cynthia Y
• Format: Article
• Language: English
• Subjects: Axoneme - metabolism; Cell Biology of Organelles in Unicellular Parasites; Cilia - metabolism; Cytoplasm - metabolism; Dyneins - metabolism; Flagella - metabolism; Microtubules - metabolism; Proteomics - methods; Protozoan Proteins - metabolism; Trypanosoma brucei brucei - metabolism
• ISSN: 1059-1524; 1939-4586; 1939-4586
• DOI: 10.1091/mbc.E24-06-0263

The outer dynein arm (ODA) is a large, multimeric protein complex essential for ciliary motility. The composition and assembly of ODA are best characterized in the green algae where individual ODA subunits are synthesized and preassembled into a mature complex in the cytosol prior to ciliary import. The single-cellular parasite contains a motile flagellum essential for cell locomotion and pathogenesis. Similar to human motile cilia, flagellum contains a two-headed ODA complex arranged at 24 nm intervals along the axonemal microtubule doublets. The subunit composition and the preassembly of the ODA complex in however, have not been investigated. In this study, we affinity-purified the ODA complex from cytoplasmic extract Proteomic analyses revealed the presence of two heavy chains (ODAα and ODAβ), two intermediate chains (IC1and IC2) and several light chains. We showed that both heavy chains and both intermediate chains are indispensable for flagellar ODA assembly. Our study also provided biochemical evidence supporting the presence of a cytoplasmic, preassembly pathway for ODA