The Aspergillus nidulans CENP-E kinesin KipA is able to dimerize and to move processively along microtubules

Kinesin molecular motors serve a variety of cellular functions usually in dynamic processes. One characteristic feature of many kinesins is their ATP-dependent processive movement along polymerized microtubules. However, many kinesins work as stationary polymerases or depolymerases. Therefore, it needs to be determined for each motor, whether it moves processively along microtubules or not. The Schizosaccharomyces pombe kinesin-7, Tea2, has been shown to be involved in cell end marker transportation towards the cortex to organize the actin cytoskeleton. In human, kinesin 7 promotes microtubule polymerization. In Aspergillus nidulans, the machinery for determining growth directionality is conserved, but there is no evidence yet that kinesin 7, KipA is potentially involved in the transportation of the cell end marker proteins, TeaA or TeaR or newly identified proteins such as KatA. We expressed KipA in Escherichia coli and determined the catalytic properties of this kinesin. Here we show that KipA is an active ATPase, which is able to dimerize and move processively along microtubules with a speed of 9.48 mu m/min.