Structural and Functional Insights into the Microtubule Organizing Centers of <em>Toxoplasma gondii</em> and <em>Plasmodium spp</em>.

Abstract

Microtubule organizing centers (MTOCs) perform critical cellular tasks by nucleating, stabilizing and anchoring microtubule&amp;rsquo;s minus ends. These capacities impact tremendously a wide array of cellular functions ranging from ascribing cell shape to orchestrating cell division and generating motile structures, among others. The phylum Apicomplexa comprises over 6000 single-celled obligate intracellular parasitic species. Many of the apicomplexan are well known pathogens such as Toxoplasma gondii and the Plasmodium species, causative agents of toxoplasmosis and malaria, respectively. Microtubule organization in these parasites is critical for organizing the cortical cytoskeleton, enabling host cell penetration and the positioning of large organelles, drive cell division and direct the formation of flagella in sexual life stages. Apicomplexans are a prime example of MTOC diversity displaying multiple functional and structural MTOCs combinations within a single species. This diversity can only be fully understood in light of each organism's specific MT nucleation requirements and their evolutionary history. Insight into apicomplexan MTOCs had traditionally been limited to classical ultrastructural work by transmission electron microscopy. However, in the past few years, a large body of molecular insight has emerged. In this work we describe the latest insights into nuclear MTOC biology in two major human and animal disease causing Apicomplexans; Toxoplasma gondii and Plasmodium spp.

An Sfi1-like centrin-interacting centriolar plaque protein affects nuclear microtubule homeostasis

“…In mammals, centrosomes act as microtubule organizing centers (MTOC) and need to duplicate only once per cell cycle [27]. The CP of asexual blood stage parasites multiplies once each nuclear cycle and contains very few conserved centrosomal proteins [28–30]. The CP serves as a nucleation site for nuclear microtubules, while cytoplasmic microtubules are absent in schizonts [3,31–34].…”