title: Modulation of the mechano-chemical properties of myosin V by drebrin-E.
abstract: The regulation of actin filament networks by various proteins has essential roles in the growth cone dynamics. In this study we focused on the actin-myosin interaction which has been suggested to be an important player in the neurite extension. We examined in vitro how the decoration of actin filaments with a side-binding protein, drebrin-E, affects the motile properties of an intracellular transporter myosin V. Single myosin V molecules landed on the drebrin-E-decorated actin filaments with a lower frequency and ran over shorter distances; however, their velocities were normal. Furthermore, the analysis of the movement of myosin V molecules in the optical trap revealed that the decoration of actin filaments with drebrin-E markedly increased the load-sensitivity of the myosin V stepping. These results are attributable to the delay in the attachment of the motor's leading head (ADP·P(i) state) to actin, induced by the competitive binding of drebrin-E to actin, whereas the rate of ADP release from the trailing head (the rate-limiting step in the ATPase cycle of myosin V) is unaffected. Our study indicates that, in addition to the regulation of binding affinity of myosin V, drebrin-E also modulates the chemo-mechanical coupling in the motile myosin V molecules, presumably affecting the movement of the growth cone.
authors.affiliation: Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kubota
authors.forename: Ryoki
authors.initials: R
authors.lastname: Ishikawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohki
authors.forename: Junji
authors.initials: J
authors.lastname: Ishizuka
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Mikhailenko
authors.forename: Shin'ichi
authors.initials: S
authors.lastname: Ishiwata
mesh_terms: D000199:Actins / Q000737:chemistry / Q000502:physiology; D009068:Movement; D024701:Myosin Type V / Q000737:chemistry* / Q000502:physiology*; D009479:Neuropeptides / Q000737:chemistry*; D052898:Optical Tweezers
chemical_list: D000199:Actins; D009479:Neuropeptides; C083795:drebrin E; D024701:Myosin Type V