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Richard McIntosh | Alan Hunt Memorial Lecture 2014

526 views · Published 17 November 2014 · 50:42 · Indexed 6 November 2026

Channel: Michigan Engineering · 2014 · Science & Technology

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"Microtubule Dynamics as an Engine for Mitotic Chromosome Motion".

Mitotic chromosomes are attached to bundles of microtubules that control their positions. These protein polymers orient each already duplicated chromosome so one copy of the chromosome becomes attached to each spindle pole; they also position the chromosomes near the midplane of a 2-fold symmetric device called the “mitotic spindle”. Then some microtubules shorten to draw one copy of each chromosome up to the spindle’s ends or “poles”, while other microtubules elongate to increase the final separation between the two chromosome sets. Some models for chromosome motion posit that microtubule growth and shortening are simply permissive for chromosome motion; motor enzymes burn ATP to generate the forces necessary for chromosome motion.  Other models see depolymerization as mechanistically significant. Dr. McIntosh will review evidence for these models and present data from Alan Hunt’s work and from his own lab that microtubule dynamics can in fact generate force. The problem a cell must therefore solve is how to couple a payload to this polymerization-depolymerization engine.  Two strategies for coupling will be described: one based on rings that encircle microtubules, the other on fibrous proteins that bind to a microtubule wall or end.  Several possible fibrous protein couplers will be described, and evidence for their roles in mitosis reviewed. Finally, Dr. McIntosh will discuss the ways in which microtubule depolymerization might be controlled during chromosome motion so some microtubules shrink while others elongate.

The Alan J. Hunt Memorial Lecture was endowed in 2013. It was established in loving memory of Alan by his family, friends and numerous colleagues in the Department of Biomedical Engineering.

Contributions in memory of Dr. Hunt can be made toward a memorial annual lecture at U of M at giving.umich.edu/AlanHunt.

This event is sponsored by the Biomedical Engineering Department:
http://www.bme.umich.edu

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