title: The CSC connects three major axonemal complexes involved in dynein regulation.
abstract: Motile cilia and flagella are highly conserved organelles that play important roles in human health and development. We recently discovered a calmodulin- and spoke-associ-ated complex (CSC) that is required for wild-type motility and for the stable assembly of a subset of radial spokes. Using cryo-electron tomography, we present the first structure-based localization model of the CSC. Chlamydomonas flagella have two full-length radial spokes, RS1 and RS2, and a shorter RS3 homologue, the RS3 stand-in (RS3S). Using newly developed techniques for analyzing samples with structural heterogeneity, we demonstrate that the CSC connects three major axonemal complexes involved in dynein regulation: RS2, the nexin-dynein regulatory complex (N-DRC), and RS3S. These results provide insights into how signals from the radial spokes may be transmitted to the N-DRC and ultimately to the dynein motors. Our results also indicate that although structurally very similar, RS1 and RS2 likely serve different functions in regulating flagellar motility.
authors: Biology Department, Rosenstiel Center, Brandeis University, Waltham, MA 02454, USA.
authors: Thomas
authors: T
authors: Heuser
authors: Erin E
authors: EE
authors: Dymek
authors: Jianfeng
authors: J
authors: Lin
authors: Elizabeth F
authors: EF
authors: Smith
authors: Daniela
authors: D
authors: Nicastro
mesh_terms: D054468:Axoneme / Q000378:metabolism* / Q000648:ultrastructure; D002147:Calmodulin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D004398:Dyneins / Q000378:metabolism*; D005407:Flagella / Q000378:metabolism / Q000648:ultrastructure; D055785:Gene Knockdown Techniques; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D034622:RNA Interference
chemical_list: D002147:Calmodulin; D010940:Plant Proteins; D004398:Dyneins