title: Axonemal dynein light chain-1 locates at the microtubule-binding domain of the γ heavy chain.
abstract: The outer arm dynein (OAD) complex is the main propulsive force generator for ciliary/flagellar beating. In Chlamydomonas and Tetrahymena, the OAD complex comprises three heavy chains (α, β, and γ HCs) and >10 smaller subunits. Dynein light chain-1 (LC1) is an essential component of OAD. It is known to associate with the Chlamydomonas γ head domain, but its precise localization within the γ head and regulatory mechanism of the OAD complex remain unclear. Here Ni-NTA-nanogold labeling electron microscopy localized LC1 to the stalk tip of the γ head. Single-particle analysis detected an additional structure, most likely corresponding to LC1, near the microtubule-binding domain (MTBD), located at the stalk tip. Pull-down assays confirmed that LC1 bound specifically to the γ MTBD region. Together with observations that LC1 decreased the affinity of the γ MTBD for microtubules, we present a new model in which LC1 regulates OAD activity by modulating γ MTBD's affinity for the doublet microtubule.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.
authors.forename: Muneyoshi
authors.initials: M
authors.lastname: Ichikawa
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Haru-Aki
authors.initials: HA
authors.lastname: Yanagisawa
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Yagi
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Ritsu
authors.initials: R
authors.lastname: Kamiya
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Yajima
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Kushida
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Nakano
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Numata
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan cyytoyo@mail.ecc.u-tokyo.ac.jp.
authors.forename: Yoko Y
authors.initials: YY
authors.lastname: Toyoshima
mesh_terms: D056444:Axonemal Dyneins / Q000378:metabolism*; D002696:Chlamydomonas / Q000201:enzymology / Q000378:metabolism; D002923:Cilia / Q000201:enzymology / Q000378:metabolism; D005407:Flagella / Q000201:enzymology / Q000378:metabolism; D008854:Microscopy, Electron / Q000379:methods; D008870:Microtubules / Q000201:enzymology / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000378:metabolism; D013768:Tetrahymena / Q000201:enzymology / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins; D056444:Axonemal Dyneins