Proceedings of the National Academy of Sciences of the United States of America
Microtubule proteins isolated from calf brain will undergo gelation-contraction in the presence of ATP. We have now examined this process by video-enhanced contrast microscopy. After ATP addition to steady-state microtubules, slow (1-5 micron/min), linear movements of particles and microtubules toward aggregation centers occur. The resulting structures resemble mitotic spindle asters. During the time when gel contraction occurs, asters move (at 1-5 micron/min) toward other nearby asters. This is accompanied by the apparent shortening of the microtubules running between the asters. This is the first example of isolated microtubules undergoing a process that has similarities to half-spindle shortening during anaphase A. Formation of aster-like structures without preformed microtubule organizing centers raises the possibility that a similar process may contribute to microtubule organization in vivo.
Weisenberg, Richard C.; Allen, Robert D.; and Inoue, Shinya, "ATP-dependent Formation and Motility of Aster-like Structures with Isolated Calf Brain Microtubule Proteins." (1986). Open Dartmouth: Faculty Open Access Articles. 1221.