Nanoscale imaging of the conoid and functional dissection of its dynamics in Apicomplexa

Abstract

Members of the Apicomplexa phylum are unified by an apical complex tailored for motility and host cell invasion. It includes regulated secretory organelles and a conoid attached to the apical polar ring (APR) from which subpellicular microtubules emerge. In coccidia, the conoid is composed of a cone of spiraling tubulin fibers, two preconoidal rings, and two intraconoidal microtubules. The conoid extrudes through the APR in motile parasites. Recent advances in proteomics, cryo-electron tomography, super-resolution, and expansion microscopy provide a more comprehensive view of the spatial and temporal resolution of proteins belonging to the conoid subcomponents. In combination with the phenotyping of targeted mutants, the biogenesis, turnover, dynamics, and function of the conoid begin to be elucidated.