Induced electrostatic charge in poleward motion of chromosomes during mitosis

Previously, I have proposed a model for post-attachment chromosome motions based on electrostatics and assumptions regarding net charge on kinetochores (KCs) and the pericentriolar material of centrosomes. The present work shows that given the electric dipole nature of tubulin, layered water associated with electric charge, and the dynamic instability of microtubules, it is possible to account for these motions within a comprehensive model based on electrostatics without making any assumptions regarding net charge on these structures—a minimal assumptions comprehensive model. Tubulin microtubule (MT) subunits are electric dipolar structures that can induce charge on a KC or centrosome matrix through the reduced permittivity of layered cytoplasmic water. Thus, prometaphase post-attachment, metaphase, and anaphase-A poleward (P) motions can be explained by nanoscale electrostatic MT dissassembly forces acting at KCs and centrosomes. With the increase in intracellular free calcium concentration at the onset of anaphase, the probability of MT disassembly is increased significantly, allowing P-directed nanoscale electrostatic MT disassembly forces acting at KCs and centrosomes to dominate and anaphase-A motion ensues. Anaphase-B motion is due to electrostatic repulsion between like-charged free ends of polar MTs originating from opposite poles.