Related Experiment Video
Updated: Sep 9, 2025

Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations
Published on: September 20, 2019
Plasmodium ARK1 regulates spindle formation during atypical mitosis and forms a divergent chromosomal passenger
Abstract:
Mitosis in Plasmodium spp., the causative agent of malaria, is fundamentally different from model eukaryotes, proceeding via a bipartite microtubule organising centre (MTOC) and lacking canonical regulators such as Polo and Bub1 kinases. During schizogony, asynchronous nuclear replication produces a multinucleate schizont, while rapid male gametogony generates an octaploid nucleus before gamete formation. Here, we identify Aurora-related kinase 1 (ARK1) as a key component of inner MTOC and spindle formation, controlling kinetochore dynamics and driving mitotic progression. Conditional ARK1 depletion disrupts spindle biogenesis, kinetochore segregation, karyokinesis and cytokinesis in both stages, and affects parasite transmission. Interactome analysis reveals ARK1 as the catalytic core of a non-canonical chromosomal passenger complex (CPC) containing two divergent inner centromere proteins (INCENPs) but lacking Survivin and Borealin. Comparative genomics indicates this CPC architecture arose early in Apicomplexa, replacing canonical centromere-targeting modules. These findings uncover a distinct mitotic machinery in Plasmodium and identify the ARK1-INCENP interface as a potential multistage target for malaria therapeutic intervention.
Related Concept Videos
Spindle Assembly
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
The Mitotic Spindle
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures...
The Spindle Assembly Checkpoint
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Forces Acting on Chromosomes
Microtubules and motor proteins exert two types of forces on...
Microtubule Associated Proteins (MAPs)
Attachment of Sister Chromatids

