Sustained rhoptry docking and discharge requires Toxoplasma gondii intraconoidal microtubule-associated proteins

Abstract

In Apicomplexa, rhoptry discharge is essential for invasion and involves an apical vesicle (AV) docking one or two rhoptries to a macromolecular secretory apparatus. Toxoplasma gondii is armed with 10–12 rhoptries and 5-6 microtubule-associated vesicles (MVs) presumably for iterative rhoptry discharge. Here, we have addressed the localization and functional significance of two intraconoidal microtubule (ICMT)-associated proteins instrumental for invasion. Mechanistically, depletion of ICMAP2 leads to a dissociation of the ICMTs, their detachment from the conoid and dispersion of MVs and rhoptries. ICMAP3 exists in two isoforms that contribute to the control of the ICMTs length and the docking of the two rhoptries at the AV, respectively. This study illuminates the central role ICMTs play in scaffolding the discharge of multiple rhoptries. This process is instrumental for virulence in the mouse model of infection and in addition promotes sterile protection against T. gondii via the release of key effectors inducing immunity.

Mosquito Tissue Ultrastructure-Expansion Microscopy (MoTissU-ExM) enables ultrastructural and anatomical analysis of malaria parasites and their mosquito

“…Apicomplexa are a phylum of largely parasitic single-celled organisms that include significant causes ofdisease in humans and livestock, such as malaria, toxoplasmosis and cryptosporidiosis. To date, U-ExM has been used to study the cell biology of Plasmodium 6,14,15 , Toxoplasma 16,17 , Cryptosporidium 7,18 , and Neospora 19 . To date, U-ExM has only been applied to parasites cultured in vitro and prepared as either isolated parasites or infected-cell monolayers.…”