Two distinct cytokinesis pathways drive trypanosome cell division initiation from opposite cell ends

Abstract

Significance Cytokinesis occurs along a cell’s short axis in many organisms, including bacteria, archaea, and eukaryotes. In many protozoa it occurs along the cell’s longitudinal axis. The mechanism underlying this mode of cytokinesis is unknown. We delineate the signaling cascade that regulates cytokinesis along the longitudinal axis of Trypanosoma brucei , which is totally different from that in its human host. Additionally, we discover an alternative cytokinesis pathway that drives trypanosome cell division along the same division plane as the typical cytokinesis, but in an opposite direction. This alternative cytokinesis is activated only when the typical cytokinesis pathway is defective, suggesting that trypanosomes have evolved a backup cytokinesis mechanism to prevent the failure of cell division, thereby ensuring survival of this organism.