Apicomplexan cell cycle flexibility: centrosome controls the clutch

Abstract

The centrosome serves as a central hub coordinating multiple cellular events in eukaryotes. A recent study in Toxoplasma gondii revealed a unique bipartite structure of the centrosome, which coordinates the nuclear cycle (S-phase and mitosis) and budding cycle (cytokinesis) of the parasite, and deciphers the principle behind flexible apicomplexan cell division modes.

Keywords: Toxoplasma gondii; apicomplexa; centrosome; endodyogeny; schizogony.

Figure 1. A model for apicomplexan parasite cell division powered by a bipartite centrosome

A haploid interphase zoite harbors inactive centrosomal inner (green) and outer (red) cores (left panel). An active inner core (bright green) drives the nuclear cycle (S-phase and mitosis; karyokinesis is optional and not covered by this model), whereas the quiescent outer core inhibits the budding cycle between the repeatedly nuclear cycles (middle panel). When both inner and outer core are active (bright green and bright red, respectively), a single round of the nuclear cycle is coupled to the budding cycle, and two daughter cells are formed per round (right panel).