Molecular characterization of axonemal proteins and signaling molecules responsible for chemoattractant-induced sperm activation in Ciona intestinalis

Authors

  • Akiko Hozumi,

    1. Shimoda Marine Research Center, University of Tsukuba, Shizuoka 415-0025, Japan
    2. Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
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  • Potturi Padma,

    1. Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
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  • Tosifusa Toda,

    1. TMIG Proteomics Collaboration Center, Tokyo Metropolitan Institute of Gerontology, Sakaecho, Itabashi-ku, Tokyo 173-0015, Japan
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  • Hiroyuki Ide,

    1. Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
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  • Kazuo Inaba

    Corresponding author
    1. Shimoda Marine Research Center, University of Tsukuba, Shizuoka 415-0025, Japan
    2. BIRD, Japan Science and Technology Corporation, Chiyoda-ku, Tokyo 102-0081, Japan
    • Shimoda Marine Research Center, University of Tsukuba, Shimoda 5-10-1, Shizuoka 415-0025, Japan
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Abstract

Spermatozoa undergo dramatic physiological changes at fertilization. In the ascidian Ciona intestinalis, an egg-derived substance named SAAF induces both sperm activation and chemotaxis to the egg. To elucidate the molecular mechanism underlying these phenomena, whole sperm proteins before and after SAAF-treatment were analyzed by two-dimensional gel electrophoresis. By comparison of spot patterns before and after activation, we found twelve proteins that changed the isoelectric points. Seven proteins were shown to be axonemal proteins and others were suggested to be non-axonemal components. Analysis of these proteins by MS-based proteomic system revealed that components of several substructures of the axonemes underwent the changes in isoelectric point at sperm activation, including WD-repeat intermediate chains of outer and inner arm dyneins and a radial spoke protein LRR37, as well as novel axonemal proteins with armadillo repeats or SMC domain. Molecules for cell signaling such as 14-3-3 proteins, Skp1 and VCP/p97 also showed isoelectric changes at sperm activation. These results show a comprehensive feature for signaling mechanism of the activation of spermatozoa at fertilization and also shed new lights on the regulation of ciliary and flagellar movements. Cell Motil. Cytoskeleton 2008. © 2008 Wiley-Liss, Inc.

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