TY - JOUR TI - Basalin is an evolutionarily unconstrained protein revealed via a conserved role in flagellum basal plate function AU - Dean, Samuel AU - Moreira-Leite, Flavia AU - Gull, Keith A2 - Bastin, Philippe A2 - Akhmanova, Anna VL - 8 PY - 2019 DA - 2019/02/27 SP - e42282 C1 - eLife 2019;8:e42282 DO - 10.7554/eLife.42282 UR - https://doi.org/10.7554/eLife.42282 AB - Most motile flagella have an axoneme that contains nine outer microtubule doublets and a central pair (CP) of microtubules. The CP coordinates the flagellar beat and defects in CP projections are associated with motility defects and human disease. The CP nucleate near a ‘basal plate’ at the distal end of the transition zone (TZ). Here, we show that the trypanosome TZ protein ‘basalin’ is essential for building the basal plate, and its loss is associated with CP nucleation defects, inefficient recruitment of CP assembly factors to the TZ, and flagellum paralysis. Guided by synteny, we identified a highly divergent basalin ortholog in the related Leishmania species. Basalins are predicted to be highly unstructured, suggesting they may act as ‘hubs’ facilitating many protein-protein interactions. This raises the general concept that proteins involved in cytoskeletal functions and appearing organism-specific, may have highly divergent and cryptic orthologs in other species. KW - transition zone KW - basal plate KW - Trypanosome KW - Leishmania KW - central pair KW - intrinsic disorder JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -