Sequential Assembly of Flagellar Radial Spokes

• Type of Material: Article
• Authors: Dennis R. Diener, Yale University; Pinfen Yang, Marquette University; Stefan Geimer, University of Bayreuth; Douglas G. Cole, University of Idaho; Winfield Sale, Emory University; Joel L. Rosenbaum, Yale University
• Language: English
• Date: 2011-07-01
• Publisher: Wiley: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2011 Wiley-Liss, Inc.
• Final Published Version (URL): http://dx.doi.org/10.1002/cm.20520
• Title of Journal or Parent Work: Cytoskeleton
• ISSN: 1949-3584
• Volume: 68
• Issue: 7
• Start Page: 389
• End Page: 400
• Grant/Funding Information: This work was supported by NIH Grant #GM14642 to JLR, R37GM51173 to WSS and GM90162 to PY.
• Keywords: INTRAFLAGELLAR TRANSPORT IFT; Science & Technology; CALMODULIN; GENE; PROTEINS; MOLECULAR-CLONING; RSP3; MODEL; Life Sciences & Biomedicine; PHOSPHORYLATION; CHLAMYDOMONAS-REINHARDTII; flagella; BACTERIOPHAGE-T4; Cell Biology; DYNEIN; cilia; Chlamydomonas
• Research Categories: Biology, Molecular; Biology, Cell

Abstract

The unicellular alga Chlamydomonas can assemble two 10 μm flagella in 1 h from proteins synthesized in the cell body. Targeting and transporting these proteins to the flagella are simplified by preassembly of macromolecular complexes in the cell body. Radial spokes are flagellar complexes that are partially assembled in the cell body before entering the flagella. On the axoneme, radial spokes are "T" shaped structures with a head of five proteins and a stalk of 18 proteins that sediment together at 20S. In the cell body, radial spokes are partially assembled; about half of the radial spoke proteins (RSPs) form a 12S complex. In mutants lacking a single RSP, smaller spoke subassemblies were identified. When extracts from two such mutants were mixed in vitro the 12S complex was assembled from several smaller complexes demonstrating that portions of the stepwise assembly of radial spoke assembly can be carried out in vitro to elucidate the order of spoke assembly in the cell body.