Unravel new components of the apical complex assembly upon Toxoplasma gondii division

ABSTRACT: During Toxoplasma gondii division, the apical complex (AC)—comprising the conoid, apical polar ring (APR), and preconoidal rings—assembles with precise spatiotemporal coordination to form functional daughter buds. Despite their essential roles in invasion, motility, and division, the scaffolding proteins orchestrating this ordered assembly have remained largely unidentified, representing a critical gap in our understanding of apicomplexan cell biology. Here, we characterize RCC1-2 and APR8 as essential scaffolding proteins directing distinct phases of daughter cell AC construction. Both proteins associate with nascent buds before conoid or subpellicular microtubule (SPMT) formation—yet vanish in mature parasites. RCC1-2 localizes beneath the most known basal layer of APR to stabilize SPMTs attachment to APR. APR8 resides within the APR basal layer and is dispensable for conoid and PCR initiation, yet its loss causes APR collapse, abolishes SPMT anchoring and arrest conoid maturation. These findings map a hierarchical RCC1-2/APR8-dependent scaffolding process that advances our understanding of parasite replication.

INSTRUMENT(S):

ORGANISM(S): Toxoplasma Gondii

DISEASE(S): Toxoplasmosis

SUBMITTER: valerie Rofidal  

LAB HEAD: Maryse Lebrun

PROVIDER: PXD074368 | Pride | 2026-10-26

REPOSITORIES: Pride