Apical Annuli: Sites of Dense Granule Secretion in Toxoplasma

Concetti Chiave

Apical annuli in Toxoplasma are specialized sites for dense granule secretion, essential for parasite growth and proliferation.

Sintesi

Abstract: Apicomplexans use secretory events to invade host cells. Micronemes and rhoptries mediate invasion, while dense granules drive host cell remodeling post-invasion.
Introduction: Apicomplexa parasites cause diseases like malaria and toxoplasmosis. The IMC limits material exchange across the plasma membrane.
Discovery of Apical Annuli: Integral membrane proteins at apical annular sites facilitate vesicle fusion and exocytosis of dense granules in Toxoplasma.
Role of Apical Annuli: Apical annuli provide essential functions for normal cell growth and are required for dense granule exocytosis.
SNARE Proteins at Apical Annuli: SNARE proteins at apical annuli sites implicate them as points for dense granule docking and exocytosis.
Implications: The physical separation of pre- and post-invasion secretion processes highlights the importance of apical annuli in host-parasite interactions.

Statistiche

"Dense granules require these structures for the secretion of their cargo proteins."
"Depletion of all four proteins showed reduced plaque development."
"Depletion resulted in delayed parasite replication at 24 hours post invasion."
"All mutants showed an average lag of one to three division cycles behind the control."

Citazioni

Approfondimenti chiave tratti da

Apical annuli are specialised sites of post-invasion secretion of dense granules in Toxoplasma

by Chelaghma,S.... alle www.biorxiv.org 07-27-2023

https://www.biorxiv.org/content/10.1101/2023.07.26.550681v2

Domande più approfondite

What implications do the findings about apical annuli have on understanding other parasitic infections

The discovery of apical annuli in Toxoplasma gondii sheds light on potential similar structures in other parasitic infections caused by apicomplexans. Understanding the role of these specialized sites for post-invasion secretion can provide insights into the pathogenic mechanisms employed by related parasites such as Plasmodium spp., which cause malaria, and Cryptosporidium spp., responsible for cryptosporidiosis. These findings may lead to further investigations into whether similar structures exist in these parasites and how they contribute to host-parasite interactions during infection.

How might the presence of apical annuli impact drug development targeting parasite-host interactions

The presence of apical annuli could have significant implications for drug development targeting parasite-host interactions. By understanding that dense granule exocytosis occurs at these specific sites, researchers can explore novel therapeutic strategies aimed at disrupting this crucial step in the parasite's life cycle. Targeting proteins involved in vesicle fusion at the apical annuli could potentially lead to the development of new antiparasitic drugs that interfere with essential processes required for parasite survival within the host cell.

What evolutionary advantages might apicomplexans gain from having specialized structures like apical annuli

Apicomplexans likely gain evolutionary advantages from having specialized structures like apical annuli due to their role in mediating distinct secretion pathways critical for successful infection and proliferation within host cells. The physical separation of pre- and post-invasion secretion processes allows for precise control over protein release, enabling efficient manipulation of host cell machinery without interference from earlier secretory events. This specialization likely enhances the efficiency and effectiveness of parasitic strategies during invasion, replication, and immune evasion, contributing to the overall fitness and adaptability of apicomplexan parasites across diverse host environments.