Roles of the tubulin-based cytoskeleton in the Toxoplasma gondii apical complex

Tell i Puig, Albert; Soldati-Favre, Dominique

doi:10.1016/j.pt.2024.02.010

Cited by 3 publications

References 115 publications

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Functional dissection of prenyltransferases reveals roles in endocytosis and secretory vacuolar sorting in type 2-ME49 strain of Toxoplasma gondii

Wang,

Wang

et al. 2024

Virulence

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Prenyltransferases act essential roles in the prenylation modification, which is significant for proteins, like small GTPases to execute various important activities in Toxoplasma gondii ( T.gondii ). The structures and partial functions of prenyltransferases (FTase, GGTase-I, and GGTase-II) in prenylation process have been dissected in T. gondii . However, the cellular effects of prenyltransferases on type 2-ME49 strain of Toxoplasma are largely unknown. To address this gap, CRISPR/Cas9-based gene-editing technology was employed to construct conditional knockdown strains of prenyltransferases in ME49 strain. Subsequent observation of ingestion ability of host cytosolic molecules (e.g, green fluorescent protein [GFP]) and status of secretory vacuolar sorting post-knockdown of prenyltransferases revealed significant findings. Our study demonstrated that degradation of FTase and GGTase-II notably affected the trafficking of endocytic GFP and vacuolar secretory trafficking to rhoptry bulb. Additionally, depletion of GGTase-II led to disordered endoplasmic reticulum and microtubules, as well as impaired gliding motility. The integrity of mitochondrion was damaged after degradation of GGTase-I. These findings underscore the critical functions of prenyltransferases in endocytosis and secretory vacuolar sorting in ME49 strain of T. gondii , thereby enhancing our understanding of prenyltransferases as potential drug targets.

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Functional dissection of prenyltransferases reveals roles in endocytosis and secretory vacuolar sorting in type 2-ME49 strain of Toxoplasma gondii

Wang,

Wang

et al. 2024

Virulence

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γ-tubulin complex controls the nucleation of tubulin-based structures in Apicomplexa

Haase,

Puthenpurackal,

Maco

et al. 2024

MBoC

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Apicomplexan parasites rely on tubulin structures throughout their cell and life cycles, particularly in the polymerization of spindle microtubules to separate the replicated nucleus into daughter cells. Additionally, tubulin structures, including conoid and subpellicular microtubules, provide the necessary rigidity and structure for dissemination and host cell invasion. However, it is unclear whether these tubulin structures are nucleated via a highly conserved γ-tubulin complex or through a specific process unique to apicomplexans. This study demonstrates that Toxoplasma γ-tubulin is responsible for nucleating spindle microtubules, akin to higher eukaryotes, facilitating nucleus division in newly formed parasites. Interestingly, γ-tubulin colocalizes with nascent conoid and subpellicular microtubules during division, potentially nucleating these structures as well. Loss of γ-tubulin results in significant morphological defects due to impaired nucleus scission and the loss of conoid and subpellicular microtubule nucleation, crucial for parasite shape and rigidity. Additionally, the nucleation process of tubulin structures involves a concerted action of γ-tubulin and Gamma Tubulin Complex proteins (GCPs), recapitulating the localization and phenotype of γ-tubulin. This study also introduces new molecular markers for cytoskeletal structures and applies iterative expansion microscopy to reveal microtubule-based architecture in Cryptosporidium parvum sporozoites, further demonstrating the conserved localization and probable function of γ-tubulin in Cryptosporidium.

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Function and interactions of a protein bridge between the inner membrane complex and subpellicular microtubules inToxoplasma gondii

Cheng,

Moon,

Barshop

et al. 2024

Preprint

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Toxoplasma gondiiis an obligate intracellular parasite that utilizes peripheral membrane and cytoskeletal structures for critical functions such as host cell invasion, replication, and maintaining cellular morphology. These structures include the inner membrane complex (IMC) as well as the underlying longitudinal subpellicular microtubules (SPMTs) that provide support for the IMC and give the parasite its distinctive crescent shape. While the IMC and SPMTs have been studied on their own, the mechanisms linking these adjacent structures remain largely unknown. This study identifies aT. gondiiprotein named IMT1 that localizes to the maternal IMC and SPMTs and thus appears to tether the IMC to the microtubules. We disrupt the IMT1 gene to assess function and then use deletion analyses and mutagenesis to reveal regions of the protein that are necessary for binding to the IMC cytoskeleton or SPMTs. Using proximity labelling with IMT1 as bait, we identify a series of candidate interactors in the IMC or SPMTs. Exploration of two of these candidates reveals that IMT1 regulates the levels of the microtubule associated protein TLAP2 and binds directly to the cytoskeletal IMC protein IMC1. Taken together, these interactions unveil the specific interactions linking two key cytoskeletal structures of the parasite and provides new insight into the organization of the structural backbone ofT. gondii.

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Roles of the tubulin-based cytoskeleton in the Toxoplasma gondii apical complex

Cited by 3 publications

References 115 publications

Functional dissection of prenyltransferases reveals roles in endocytosis and secretory vacuolar sorting in type 2-ME49 strain of Toxoplasma gondii

Functional dissection of prenyltransferases reveals roles in endocytosis and secretory vacuolar sorting in type 2-ME49 strain of Toxoplasma gondii

γ-tubulin complex controls the nucleation of tubulin-based structures in Apicomplexa

Function and interactions of a protein bridge between the inner membrane complex and subpellicular microtubules inToxoplasma gondii

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