title: Molecular characterization of radial spoke subcomplex containing radial spoke protein 3 and heat shock protein 40 in sperm flagella of the ascidian Ciona intestinalis.
abstract: Members of the heat-shock protein (HSP)40 regulate the protein folding activity of HSP70 proteins and help the functional specialization of this molecular chaperone system in various types of cellular events. We have recently identified Hsp40 as a component of flagellar axoneme in the ascidian Ciona intestinalis, suggesting a correlation between Hsp40 related chaperone system and flagellar function. In this study, we have found that Ciona 37-kDa Hsp40 is extracted from KCl-treated axonemes with 0.5 M KI solution and comigrates with radial spoke protein (RSP)3 along with several proteins as a complex through gel filtration and ion exchange columns. Peptide mass fingerprinting with matrix-assisted laser desorption ionization/time of flight/mass spectrometry revealed that other proteins in the complex include a homolog of sea urchin spokehead protein (homolog of RSP4/6), a membrane occupation and recognition nexus repeat protein with sequence similarity with meichroacidin, and a functionally unknown 33-kDa protein. A spoke head protein, LRR37, is not included in the complex, suggesting that the complex constructs the stalk of radial spoke. Immunoelectron microscopy indicates that Hsp40 is localized in the distal portion of spoke stalk, possibly at the junction between spoke head and the stalk.
authors.affiliation: Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Yuhkoh
authors.initials: Y
authors.lastname: Satouh
authors.forename: Potturi
authors.initials: P
authors.lastname: Padma
authors.forename: Toshifusa
authors.initials: T
authors.lastname: Toda
authors.forename: Nori
authors.initials: N
authors.lastname: Satoh
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ide
authors.forename: Kazuo
authors.initials: K
authors.lastname: Inaba
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D002938:Ciona intestinalis / Q000737:chemistry* / Q000166:cytology; D020224:Expressed Sequence Tags; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D015870:Gene Expression; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry; D007211:Indoles; D008297:Male; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D008970:Molecular Weight; D010449:Peptide Mapping; D010802:Phylogeny; D011193:Potassium Iodide / Q000494:pharmacology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013082:Sperm Tail / Q000737:chemistry* / Q000648:ultrastructure; D014018:Tissue Distribution
chemical_list: D005456:Fluorescent Dyes; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D007211:Indoles; D011193:Potassium Iodide; C007293:DAPI