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Updated: Aug 19, 2026

Phosphopeptide Analysis of Rodent Epididymal Spermatozoa
Published on: December 30, 2014
Involvement of protein-tyrosine phosphorylation and dephosphorylation in sperm-induced Xenopus egg activation
1Laboratory of Molecular Biology, Biosignal Research Center, Kobe University, Nada, Japan. ksato@inherit.biosig.kobe-u.ac.jp
Abstract:
We have analyzed tyrosine-phosphorylated proteins in Xenopus laevis eggs before and after fertilization by immunoblotting with anti-phosphotyrosine antibody. A number of egg proteins with different subcellular distribution became tyrosine-phosphorylated or dephosphorylated within 30 min after insemination. Tyrosine kinase-specific inhibitors genistein and herbimycin A were found to inhibit sperm-induced egg activation judged by the egg cortical contraction. Surprisingly, sodium orthovanadate, a tyrosine phosphatase inhibitor, also inhibited the egg activation. Moreover, we found that fertilization-dependent tyrosine dephosphorylation of 42-kDa mitogen-activated protein kinase was inhibited in genistein-treated eggs. These results suggest that both protein-tyrosine phosphorylation and dephosphorylation pathways play an important role in the sperm-induced Xenopus egg activation.
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