Proteomic profiling reveals compartment-specific, novel functions of ascidian sperm proteins

Mia Nakachi, Ayako Nakajima, Mamoru Nomura, Kouki Yonezawa, Keisuke Ueno, Toshinori Endo, Kazuo Inaba*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


In this study, we performed extensive proteomic analysis of sperm from the ascidian Ciona intestinalis. Sperm were fractionated into heads and flagella, followed by further separation into Triton X-100-soluble and -insoluble fractions. Proteins from each fraction and whole sperm were separated by isoelectric focusing using two different pH ranges, followed by SDS-PAGE at two different polyacrylamide concentrations. In total, 1,294 protein spots representing 304 non-redundant proteins were identified by mass spectrometry (MALDI-TOF). On comparison of the proteins in each fraction, we were able to identify the proteins specific to different sperm compartments. Further comparison with the testis proteome allowed the pairing of proteins with sperm-specific functions. Together with information on gene expression in developing embryos and adult tissues, these results provide insight into novel cellular and functional aspects of sperm proteins, such as distinct localization of actin isoforms, novel Ca 2+-binding proteins in axonemes, localization of testis-specific serine/threonine kinase, and the presence of G-protein coupled signaling and ubiquitin pathway in sperm flagella.

Original languageEnglish (US)
Pages (from-to)529-549
Number of pages21
JournalMolecular Reproduction and Development
Issue number7
StatePublished - Jul 2011
Externally publishedYes

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology
  • Cell Biology


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