Poster: Cytoskeleton: Structure & Function
Abs #
1125: The Arabidopsis C-terminal Kinesin, ATK5: A Mitotic Motor?
Kinesins are mechanoenzymes that use the energy derived from the hydrolysis of ATP to move unidirectionally along microtubules while carrying specific cargo. A kinesin's cellular role can be hypothesized from the direction the kinesin "walks" along a microtubule (i.e. to the plus or minus end), and from determining its specific cargo (e.g. vesicles, organelles, chromosomes etc.) Here we show that the C-terminal Arabidopsis kinesin, ATK5, moves unidirectionally toward microtubule minus ends in a non-processive manner (requires more than one motor to move cargo). Additionally, we present evidence for an additional microtubule binding site in the N-terminal tail domain of the protein, implicating microtubules as the cellular cargo of ATK5. These properties, in addition to its localization in the pre-prophase band, mitotic spindle, and phragmoplast, are consistent with the properties of a mitotic motor. In support of this hypothesis, we previously showed that Ds insertion mutants in the atk1 gene, which shows 83% overall amino acid similarity to ATK5, were defective in both meiotic and mitotic spindles (Chen et al (2002) Development, 129; Marcus et al (2003) Mol. Biol. Cell. (in progress)).
