This invention provides methods for the screening and identification of
agents having potent effects on the progression of the cell cycle. In one
embodiment, the methods involve contacting a polymerized microtubule with
a microtubule severing protein or a microtubule depolymerizing protein in
the presence of an ATP or a GTP and a test agent; and (ii) detecting the
formation of tubulin monomers, dimers or oligomers. The p60 subunit of
katanin provides a particularly preferred microtubule severing protein
possessing both ATPase and microtubule severing activities.
