Center for Tropical and Emerging Global Diseases
University of Georgia
Calmodulin is a conserved EF-hand Ca2+ sensor that transduces intracellular Ca2+ signals through interactions with target proteins. Recent cryo-electron microscopy studies revealed the Toxoplasma gondii calmodulin (TgCaM) as a light chain associated with the neck of the unconventional myosin MyoL within the preconoidal P2 ring , a key component of the conoid involved in parasite …
As a master of host-cell reprogramming, Toxoplasma gondii (T. gondii) tachyzoites manipulate diverse signaling networks to establish a niche permissive for long-term infection. While the parasite’s subversion of canonical NF-κB signaling (p65/p50) is well established, how infection impacts the non-canonical NF-κB pathway has been largely unexplored. Here, we report that T. gondii infection induces nuclear accumulation of the non-canonical …
Apicomplexan parasites like Toxoplasma gondii harbor a divergent mitochondrial proteome, much of which remains uncharacterized despite its essentiality for parasite survival. One such essential pathway is ubiquinone (UQ) biosynthesis. Here, we characterize the UQ synthesis machinery in T. gondii and show that conserved enzymes, TgCoq3 and TgCoq5, are essential for growth and mitochondrial function, and …
Ca2+ signaling in cells begins with the opening of Ca2+ channels in either the plasma membrane (PM) or endoplasmic reticulum (ER), leading to a sharp increase in the physiologically low (<100 nM) cytosolic Ca2+ level. The temporal and spatial regulation of Ca²+ is crucial for the precise activation of key biological processes. In the …
Toxoplasma gondii is a highly successful intracellular mammalian and avian pathogen that must adapt to a wide range of intracellular and extracellular environments. A mechanism that may support this is the modification of hydroxyamino acid rich sequences of nucleocytoplasmic proteins with O-fucose. O-fucosylation of possibly hundreds of proteins is mediated by a single highly …
We investigated the antiparasitic activity of several antimicrobial drug leads against Toxoplasma gondii tachyzoites and, in one case, bradyzoites. Carbazole and phenylthiazole aminoguanidine anti-infectives, originally developed as antibacterial and antifungal agents, showed potent activity, with IC50 values as low as 2 μM. This potency was comparable to that observed with the tuberculosis drug candidate SQ109 and a series …
The cytosolic Ca2+ concentration of all cells is highly regulated demanding the coordinated operation of Ca2+ pumps, channels, exchangers and binding proteins. In the protozoan parasite Toxoplasma gondii calcium homeostasis, essential for signaling, governs critical virulence traits. However, the identity of most molecular players involved in signaling and homeostasis in T. gondii are unknown or …
Diego Huet works in molecular parasitology, focusing on the organellar biology of Toxoplasma gondii. In this mSphere of Influence article, he reflects on how the article “Efficient proximity labeling in living cells and organisms with turboID” (Branon et al., 2018) impacted his research and the strategies used to dissect inter-organellar interactions in T. gondii. Diego …
The production of energy in the form of ATP by the mitochondrial ATP synthase must be tightly controlled. One well-conserved form of regulation is mediated via ATPase inhibitory factor 1 (IF1), which governs ATP synthase activity and gene expression patterns through a cytoprotective process known as mitohormesis. In apicomplexans, the processes regulating ATP synthase activity …