Modeling the processive movement of dimerized kinesin-10 NOD motors

Chromokinesin NOD is a member of kinesin-10 family. It is monomeric in solution, lacking the capacity for movement on microtubules, but when dimerized can move directionally and processively towards microtubule plus ends by hydrolyzing ATP molecules, which is responsible for driving chromosome arms towards the spindle equator during metaphase of mitosis. Prior experimental data showed puzzlingly that the NOD head in nucleotide-free state has a high affinity to microtubule, whereas in any nucleotide-bound state has a low affinity. Due to these puzzling experimental data, it is perplexing how the dimerized NOD motor can move directionally and processively on microtubule. Here, based on the peculiar characteristic of the nucleotide-dependent affinity of the NOD head to microtubule and inspired by previously proposed models for better-studied dimeric kinesin-1 motors, three models are presented for the processive movement of the dimerized NOD motor, with which the dynamics of the motor is studied theoretically. The theoretical results with one of the three models can explain well the directional and processive movement of the NOD dimer. Furthermore, predicted results with the model are provided. In addition, a similar model is presented for the directional and processive movement of another species of kinesin-10 chromokinesin—dimerized human KID.