title: The conserved ciliary protein Bug22 controls planar beating of Chlamydomonas flagella.
abstract: Eukaryotic flagella and cilia can exhibit planar and non-planar beating, and the mechanism controlling these beating patterns is not well understood. Chlamydomonas reinhardtii flagella beat in approximately the same plane with either an asymmetric ciliary-type or symmetric flagellar-type waveform. Each B-tubule of the number 1, 5 and 6 doublets of the flagellar axoneme possesses a beak-like structure. The number 5 and 6 beak structures are implicated in conversion of ciliary motion into flagellar motion. Here, we show that in a null mutant of Bug22, the asymmetric ciliary waveform is converted into a three-dimensional (non-planar) symmetric flagellar waveform. Bug22 is localized to approximately the proximal half to two-thirds of the flagellum, similar to localization of beak-like structures. However, as shown by immunogold labeling, Bug22 associates with axonemal microtubules without apparent preference for any particular doublets. Interestingly, bug22 mutants lack all beak-like structures. We propose that one function of Bug22 is to regulate the anchoring of the beak-like structures to the doublet microtubules and confine flagellar beating to a plane.
authors.affiliation: MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Meng
authors.forename: Muqing
authors.initials: M
authors.lastname: Cao
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Oda
authors.forename: Junmin
authors.initials: J
authors.lastname: Pan
mesh_terms: D054468:Axoneme / Q000378:metabolism; D002465:Cell Movement; D016825:Chlamydomonas reinhardtii / Q000502:physiology* / Q000648:ultrastructure; D002923:Cilia / Q000378:metabolism*; D017124:Conserved Sequence; D005407:Flagella / Q000502:physiology* / Q000648:ultrastructure; D008870:Microtubules / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D010940:Plant Proteins
keywords: Bug22; Chlamydomonas; Cilia; Cilia motility; Flagella; Planar beating