The ATPase Cycle of the Mitotic Motor CENP-E |
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| Authors: | Steven S Rosenfeld Marilyn van Duffelen William M Behnke-Parks Christopher Beadle John Corrreia and Jun Xing |
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| Institution: | From the Departments of ¶Biology, ;‡Neurology, and ;§Cell Biology and Pathology, Columbia University, New York, New York 10032, ;the ‖Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi 39216, and ;the **Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294 |
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| Abstract: | We have previously shown that the mitotic motor centrosome protein E (CENP-E) is capable of walking for more than 250 steps on its microtubule track without dissociating. We have examined the kinetics of this molecular motor to see if its enzymology explains this remarkable degree of processivity. We find that like the highly processive transport motor kinesin 1, the enzymatic cycle of CENP-E is characterized by rapid ATP binding, multiple enzymatic turnovers per diffusive encounter, and gating of nucleotide binding. These features endow CENP-E with a high duty cycle, a prerequisite for processivity. However, unlike kinesin 1, neck linker docking in CENP-E is slow, occurring at a rate closer to that for Eg5, a mitotic kinesin that takes only 5–10 steps per processive run. These results suggest that like kinesin 1, features outside of the catalytic domain of CENP-E may also play a role in regulating the processive behavior of this motor. |
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