Abstract
AbstractCytokinesis, the last step in cell division, leads to the separation of daughter cells. This evolutionarily conserved process requires the force generated by an actomyosin contractile ring assembled at the equatorial plane. A newly discovered ion channel Pkd2 localizes to the equatorial plane and its activation by membrane-stretching promotes the cytokinetic calcium spikes in the fission yeastSchizosacchromyces pombecells. Here, we investigated whether Pkd2 plays a direct role in the assembly and constriction of the contractile ring through quantitative fluorescence microscopy and genetic analyses. The localization of type II myosin Myo2, its regulatory light chain Rlc1 and actin filaments all increased in the contractile ring of a hypomorphic mutantpkd2-81KD, compared to the wild type. This was accompanied by a significant increase of the intracellular concentration of Rlc1 and actin filaments. A strong negative interaction existed betweenpkd2-81KDand the temperature-sensitive mutantmyo2-E1. Thepkd2 myo2double mutant cells failed to assemble a complete contractile ring and separate efficiently, even at the permissive temperature. We conclude that Pkd2 modulates the assembly of myosin and actin in the contractile ring, suggesting that this ion channel mediates a novel pathway to regulate the actin cytoskeletal dynamics during cytokinesis.
Publisher
Cold Spring Harbor Laboratory