The Kinesin-5 AtKRP125b Is a Processive, Microtubule-Sliding Motor Protein with Putative Plant-Specific Functions.

The formation and maintenance of the mitotic spindle during cell division requires several microtubule-interacting motor proteins. Members of the kinesin-5 family play an essential role in the bipolar organization of the spindle. These highly conserved, homotetrameric proteins cross-link anti-parallel microtubules and slide them apart to elongate the spindle during the equal separation of chromosomes.

A Tug-of-War Model Explains the Saltatory Sperm Cell Movement in Pollen Tubes by Kinesins With Calponin Homology Domain.

Upon pollination, two sperm cells are transported inside the growing pollen tube toward the apex. One sperm cell fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei to form the triploid endosperm. In Arabidopsis thaliana, the transport of the two sperm cells is characterized by sequential forward and backward movements with intermediate pauses.