title: Spontaneous detachment of the leading head contributes to myosin VI backward steps.
abstract: Myosin VI is an ATP driven molecular motor that normally takes forward and processive steps on actin filaments, but also on occasion stochastic backward steps. While a number of models have attempted to explain the backwards steps, none offer an acceptable mechanism for their existence. We therefore performed single molecule imaging of myosin VI and calculated the stepping rates of forward and backward steps at the single molecule level. The forward stepping rate was proportional to the ATP concentration, whereas the backward stepping rate was independent. Using these data, we proposed that spontaneous detachment of the leading head is uncoupled from ATP binding and is responsible for the backward steps of myosin VI.
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Ikezaki
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Komori
authors.forename: Toshio
authors.initials: T
authors.lastname: Yanagida
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000465:Algorithms; D056966:Excitation Contraction Coupling / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000502:physiology*; D011485:Protein Binding
chemical_list: D020409:Molecular Motor Proteins; C089785:myosin VI; D000255:Adenosine Triphosphate; D018995:Myosin Heavy Chains