Study on flexural rigidity and lattice structure of microtubules stabilized by paclitaxel and laulimalide

Abstract

Microtubules (MTs) are hollow 25 nm diameter protein nanotubes comprised of dimeric alpha- and betatubulin subunits. One of the major components of the eukaryotic cytoskeleton, MTs are essentially involved in cell morphology, intracellular trafficking, and cell division. Paclitaxel (PTX) is a well known MT-targeting anticancer drug that stabilizes MT, suppressing cell division. Another MT stabilizer that is known to prevent cell mitosis is laulimalide (LMD). Although PTX and LMD both suppress MT dynamics, they attach to different binding sites of the tubulin dimer. Their influence on the structural and mechanical properties of MTs, however, is not clearly understood. We show our recent findings on the effects of PTX and LMD regulating the lattice structure using cryogenic electron microscopy (cryo-EM). To investigate the flexural rigidity of MTs, studies were conducted using transmission electron microscopy (TEM), confocal microscopy, and epi-fluorescence imaging.