Effect of Active Kinesin Motor Density on Microtubules During Self-Assembly of Spools

Abstract

Active self-assembly systems are energy driven and can organize into various structures. Microtubules and their associated motor proteins, such as kinesin, are widely used to study active self-assembly of higher order structures, such as linear bundles and spools. Microtubules are polymers composed of tubulin that are found in the cytoskeleton. Kinesin motors convert ATP into energy through hydrolysis and walk along microtubules. Microtubules functionalized with biotin and streptavidin bind together and form bundles and spools when gliding. The spools are able to maintain their shape and continue to rotate in the presence of ATP. We use gliding assays to investigate the effect of the active motor density on microtubules during spool formation. By tuning the velocity of gliding microtubules, we can effectively tune the kinesin density on microtubules. There was no significant change in average spool circumference and no reduction in spool density over a 10-fold reduction in microtubule gliding velocity. We find spool characteristics are robust against active kinesin density on microtubules.