title: Mechanosignaling between central apparatus and radial spokes controls axonemal dynein activity.
abstract: Cilia/flagella are conserved organelles that generate fluid flow in eukaryotes. The bending motion of flagella requires concerted activity of dynein motors. Although it has been reported that the central pair apparatus (CP) and radial spokes (RSs) are important for flagellar motility, the molecular mechanism underlying CP- and RS-mediated dynein regulation has not been identified. In this paper, we identified nonspecific intermolecular collision between CP and RS as one of the regulatory mechanisms for flagellar motility. By combining cryoelectron tomography and motility analyses of Chlamydomonas reinhardtii flagella, we show that binding of streptavidin to RS heads paralyzed flagella. Moreover, the motility defect in a CP projection mutant could be rescued by the addition of exogenous protein tags on RS heads. Genetic experiments demonstrated that outer dynein arms are the major downstream effectors of CP- and RS-mediated regulation of flagellar motility. These results suggest that mechanosignaling between CP and RS regulates dynein activity in eukaryotic flagella.
authors.affiliation: Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Oda
authors.forename: Haruaki
authors.initials: H
authors.lastname: Yanagisawa
authors.forename: Toshiki
authors.initials: T
authors.lastname: Yagi
authors.forename: Masahide
authors.initials: M
authors.lastname: Kikkawa
mesh_terms: D056444:Axonemal Dyneins / Q000378:metabolism / Q000502:physiology*; D016825:Chlamydomonas reinhardtii / Q000378:metabolism* / Q000648:ultrastructure; D055032:Electron Microscope Tomography; D005407:Flagella / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D040542:Mechanotransduction, Cellular; D010766:Phosphorylation; D010940:Plant Proteins / Q000032:analysis / Q000378:metabolism
chemical_list: D010940:Plant Proteins; C060324:radial spoke protein, Chlamydomonas; D056444:Axonemal Dyneins