title: Structure and function of outer dynein arm intermediate and light chain complex.
abstract: The outer dynein arm (ODA) is a molecular complex that drives the beating motion of cilia/flagella. Chlamydomonas ODA is composed of three heavy chains (HCs), two ICs, and 11 light chains (LCs). Although the three-dimensional (3D) structure of the whole ODA complex has been investigated, the 3D configurations of the ICs and LCs are largely unknown. Here we identified the 3D positions of the two ICs and three LCs using cryo-electron tomography and structural labeling. We found that these ICs and LCs were all localized at the root of the outer-inner dynein (OID) linker, designated the ODA-Beak complex. Of interest, the coiled-coil domain of IC2 extended from the ODA-Beak to the outer surface of ODA. Furthermore, we investigated the molecular mechanisms of how the OID linker transmits signals to the ODA-Beak, by manipulating the interaction within the OID linker using a chemically induced dimerization system. We showed that the cross-linking of the OID linker strongly suppresses flagellar motility in vivo. These results suggest that the ICs and LCs of the ODA form the ODA-Beak, which may be involved in mechanosignaling from the OID linker to the HCs.
authors: Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan Department of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan toda@yamanashi.ac.jp.
authors: Toshiyuki
authors: T
authors: Oda
authors: Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan.
authors: Tatsuki
authors: T
authors: Abe
authors: Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan.
authors: Haruaki
authors: H
authors: Yanagisawa
authors: Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan.
authors: Masahide
authors: M
authors: Kikkawa
mesh_terms: D056444:Axonemal Dyneins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D054468:Axoneme / Q000378:metabolism / Q000502:physiology; D016825:Chlamydomonas reinhardtii / Q000378:metabolism* / Q000502:physiology; D002923:Cilia / Q000378:metabolism* / Q000502:physiology; D055032:Electron Microscope Tomography; D005407:Flagella / Q000378:metabolism* / Q000502:physiology; D046912:Multiprotein Complexes; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D020836:Protein Structure, Quaternary
chemical_list: D046912:Multiprotein Complexes; D010940:Plant Proteins; D056444:Axonemal Dyneins