Torque generation by axonemal outer-arm dynein.

ABSTRACT: Outer-arm dynein is the main engine providing the motive force in cilia. Using three-dimensional tracking microscopy, we found that contrary to previous reports Tetrahymena ciliary three-headed outer-arm dynein (???) as well as proteolytically generated two-headed (??) and one-headed (?) subparticles showed clockwise rotation of each sliding microtubule around its longitudinal axis in microtubule corkscrewing assays. By measuring the rotational pitch as a function of ATP concentration, we also found that the microtubule corkscrewing pitch is independent of ATP concentration, except at low ATP concentrations where the pitch generated by both three-headed ??? and one-headed ? exhibited significantly longer pitch. In contrast, the pitch driven by two-headed ?? did not display this sensitivity. In the assays on lawns containing mixtures of ? and ?? at various ratios, the corkscrewing pitch increased dramatically in a nonlinear fashion as the ratio of ? in the mixture increased. Even small proportions of ?-subparticle could significantly increase the corkscrewing pitch of the mixture. Our data show that torque generation does not require the three-headed outer-arm dynein (???) but is an intrinsic property of the subparticles of axonemal dyneins and also suggest that each subparticle may have distinct mechanical properties.

SUBMITTER: Yamaguchi S 

PROVIDER: S-EPMC4336377 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature