Session S7 - Molecular Motors and the Physics of Cell Division.
INVITED session, Wednesday afternoon, March 24
516C, Palais des Congres
Mitosis, the process by which identical copies of the replicated genome are distributed to the daughter products of each cell division, depends upon the action of a microtubule(MT)-based protein machine, the mitotic spindle. Mitosis was discovered in the 1800s and by 1950 the basic events of the process had been documented by light microscopists. Subsequent studies have provided a sophisticated explanation of the molecular mechanism of mitotis in terms of MT polymer ratchets and mitotic motors. Key advances included Inoue's proposal that MT-polymer dynamics could drive chromosome motility, leading to the purification of tubulin and the realization that spindle MTs display dynamic instability and poleward flux; McIntosh's hypothesis that mitotic motility involves a "sliding filament mechanism" leading to the discovery of MT-sliding mitotic motors; Ostergren's proposal that chromosome motility depends upon a balance of antagonistic forces; and Niklas' measurements of the magnitude of spindle forces. Recent studies performed in Drosophila embryos have illuminated how multiple mitotic motors and MT polymer ratchets cooperate to coordinate spindle pole dynamics and chromosome motility, aspects of which can now be described using quantitative models.