A conserved GTPase complex gates exocytosis for defence and parasitism across alveolates
Abstract
Regulated protein secretion is a fundamental process by which eukaryotic cells respond to and interact with their dynamic environments, yet its mechanism outside metazoans remains largely unknown. Here we uncover an atypical small GTPase complex (Nd-GTPase-Nd9-NdP1) conserved across the Alveolata-a major eukaryotic clade encompassing ciliates and apicomplexan parasites-that gates organelle exocytosis for diverse functions ranging from cellular defence to host invasion. Using Tetrahymena thermophila and Toxoplasma gondii as comparative models, we combine functional genetics, cryo-electron tomography and integrative structural modelling to show that this complex maintains the organelle secretory apparatus in a pre-secretion state and permits activation upon stimulation. Comparative analysis further reveals that apicomplexan parasites rely on an apical vesicle to tighten control over secretion. These findings define a unifying principle of gated alveolate exocytosis, illustrating how evolution remodels an ancient secretion system to meet specialized cellular demands, and underlie key mechanisms of parasite virulence.
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BibTeX
@article{cova2026conserved,
title = {{A conserved GTPase complex gates exocytosis for defence and parasitism across alveolates}},
author = {Marta Mendonça Cova and Lucas Morley and Marjorie Maynadier and Jason Delabre and Arnault Graindorge and Laurence Berry-Sterkers and Shrawan Kumar Mageswaran and Valérie Rofidal and Cameron J Powell and Martin J Boulanger and Yi-Wei Chang and Daniela Sparvoli and Maryse Lebrun},
journal = {Nature Microbiology},
year = {2026},
month = oct,
doi = {10.1038/s41564-026-02501-5},
url = {https://hal.inrae.fr/hal-05828923v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A conserved GTPase complex gates exocytosis for defence and parasitism across alveolates
AU - Marta Mendonça Cova
AU - Lucas Morley
AU - Marjorie Maynadier
AU - Jason Delabre
AU - Arnault Graindorge
AU - Laurence Berry-Sterkers
AU - Shrawan Kumar Mageswaran
AU - Valérie Rofidal
AU - Cameron J Powell
AU - Martin J Boulanger
AU - Yi-Wei Chang
AU - Daniela Sparvoli
AU - Maryse Lebrun
PY - 2026
DA - 2026/10/02
JO - Nature Microbiology
DO - 10.1038/s41564-026-02501-5
UR - https://hal.inrae.fr/hal-05828923v1
AB - Regulated protein secretion is a fundamental process by which eukaryotic cells respond to and interact with their dynamic environments, yet its mechanism outside metazoans remains largely unknown. Here we uncover an atypical small GTPase complex (Nd-GTPase-Nd9-NdP1) conserved across the Alveolata-a major eukaryotic clade encompassing ciliates and apicomplexan parasites-that gates organelle exocytosis for diverse functions ranging from cellular defence to host invasion. Using Tetrahymena thermophila and Toxoplasma gondii as comparative models, we combine functional genetics, cryo-electron tomography and integrative structural modelling to show that this complex maintains the organelle secretory apparatus in a pre-secretion state and permits activation upon stimulation. Comparative analysis further reveals that apicomplexan parasites rely on an apical vesicle to tighten control over secretion. These findings define a unifying principle of gated alveolate exocytosis, illustrating how evolution remodels an ancient secretion system to meet specialized cellular demands, and underlie key mechanisms of parasite virulence.
SN - 2058-5276
SN - 2058-5276
ER -