Depolymerization of brain microtubules by skeletal muscle myosin.

Brain microtubules are found to disperse rods of skeletal muscle myosin and become decorated with amorphous aggregates of myosin. Then microtubules are partially depolymerized by myosin. Myosin shows high Mg2+-GTPase activity which is not influenced by microtubules, and induces the partial depolymerization of microtubules by exhaustion of GTP in the solution. H-meromyosin depolymerizes microtubules like myosin does. H-meromyosin is, however, contaminated with a trace amount of trypsin, which irreversibly depolymerizes microtubules.