title: Docking and rolling, a model of how the mitotic motor Eg5 works.
abstract: Whereas kinesin I is designed to transport cargoes long distances in isolation, a closely related kinesin motor, Eg5, is designed to generate a sustained opposing force necessary for proper mitotic spindle formation. Do the very different roles for these evolutionarily related motors translate into differences in how they generate movement? We have addressed this question by examining when in the ATPase cycle the Eg5 motor domain and neck linker move through the use of a series of novel spectroscopic probes utilizing fluorescence resonance energy transfer, and we have compared our results to kinesin I. Our results are consistent with a model in which movement in Eg5 occurs in two sequential steps, an ATP-dependent docking of the neck linker, followed by a rotation or "rolling" of the entire motor domain on the microtubule surface that occurs with ATP hydrolysis. These two forms of movement are consistent with the functions of a motor designed to generate sustained opposing force, and hence, our findings support the argument that the mechanochemical features of a molecular motor are shaped more by the demands placed on it than by its particular family of origin.
authors.affiliation: Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA. sr2327@columbia.edu
authors.forename: Steven S
authors.initials: SS
authors.lastname: Rosenfeld
authors.forename: Jun
authors.initials: J
authors.lastname: Xing
authors.forename: Geraldine M
authors.initials: GM
authors.lastname: Jefferson
authors.forename: Peter H
authors.initials: PH
authors.lastname: King
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry; D000251:Adenosine Triphosphatases / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000737:chemistry; D001665:Binding Sites; D002264:Carboxylic Acids / Q000494:pharmacology; D020134:Catalytic Domain; D003545:Cysteine / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D019143:Evolution, Molecular; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D016547:Kinesins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism; D008938:Mitosis; D008954:Models, Biological; D008956:Models, Chemical; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D014364:Tryptophan / Q000737:chemistry
chemical_list: D002264:Carboxylic Acids; C470243:KIF11 protein, human; C436864:Oregon Green 488 carboxylic acid; D000244:Adenosine Diphosphate; D014364:Tryptophan; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D016547:Kinesins; D003545:Cysteine