Fig 10. Working model showing the molecular organisation and dynamics of the bipartite Plasmodium MTOC coordinating mitosis and axoneme formation during microgametogenesis.

In the non-activated microgametocyte the intranuclear body is connected to the amorphous MTOC across the nuclear membrane. The amorphous MTOC corresponds to a deuterosome-like structure where components of the basal body and associated proteins localise in distinct or overlapping subdomains. The molecular organisation of the amorphous MTOC and its link with the intranuclear body relies on SRPK1. Upon activation of CDPK4, the intranuclear body gives rise to eight intranuclear bodies that coordinate the assembly of mitotic spindle while the amorphous MTOC differentiates into eight basal bodies to form eight axonemes (one representation shown). γ-tubulin shows dynamic localisation from the amorphous MTOC to the basal bodies and the intranuclear bodies to sequentially nucleate microtubules of the axonemes and mitotic spindles.