Do All Coccidia Follow the Same Trafficking Rules?

• Main Authors: Virginia Marugan-Hernandez, Gonzalo Sanchez-Arsuaga, Sue Vaughan, Alana Burrell, Fiona M. Tomley
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Life
• Subjects: Coccidia; <i>Eimeria</i> species; <i>Toxoplasma gondii</i>; protein trafficking; apical complex; endogenous development
• Online Access: https://www.mdpi.com/2075-1729/11/9/909

The Coccidia are a subclass of the Apicomplexa and include several genera of protozoan parasites that cause important diseases in humans and animals, with <i>Toxoplasma gondii</i> becoming the ‘model organism’ for research into the coccidian molecular and cellular processes. The amenability to the cultivation of <i>T. gondii</i> tachyzoites and the wide availability of molecular tools for this parasite have revealed many mechanisms related to their cellular trafficking and roles of parasite secretory organelles, which are critical in parasite-host interaction. Nevertheless, the extrapolation of the <i>T. gondii</i> mechanisms described in tachyzoites to other coccidian parasites should be done carefully. In this review, we considered published data from <i>Eimeria</i> parasites, a coccidian genus comprising thousands of species whose infections have important consequences in livestock and poultry. These studies suggest that the Coccidia possess both shared and diversified mechanisms of protein trafficking and secretion potentially linked to their lifecycles. Whereas trafficking and secretion appear to be well conversed prior to and during host-cell invasion, important differences emerge once endogenous development commences. Therefore, further studies to validate the mechanisms described in <i>T. gondii</i> tachyzoites should be performed across a broader range of coccidians (including <i>T. gondii</i> sporozoites). In addition, further genus-specific research regarding important disease-causing Coccidia is needed to unveil the individual molecular mechanisms of pathogenesis related to their specific lifecycles and hosts.