Allele-specific activators and inhibitors for kinesin

Members of the kinesin superfamily are force-generating ATPases that drive movement and influence cytoskeleton organization in cells. Often, more than one kinesin is implicated in a cellular process, and many kinesins are pro posed to have overlapping functions. By using conventional kinesin as a mod el system, we have developed an approach to activate or inhibit a specific kinesin allele in the presence of other similar motor proteins. Modified AT P analogs are described that do not activate either conventional kinesin or another superfamily member, Eg5, However, a kinesin allele with Arg-14 in its nucleotide binding pocket mutated to alanine can use a subset of these nucleotide analogs to drive microtubule gliding. Cyclopentyl-ATP is one suc h analog. Cyclopentyl-adenylylimidodiphosphate, a nonhydrolyzable form of t his analog, inhibits the mutant allele in microtubule-gliding assays, but n ot wild-type kinesin or Eg5. We anticipate that the incorporation of kinesi n mutants and allele-specific activators and inhibitors in in vitro assays should clarify the role of individual motor proteins in complex cellular pr ocesses.