Involvement of protein-tyrosine phosphorylation and dephosphorylation in sperm-induced Xenopus egg activation
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.
- Publication:
-
FEBS Letters
- Pub Date:
- January 1998
- DOI:
- 10.1016/S0014-5793(98)00123-9
- Bibcode:
- 1998FEBSL.424..113S
- Keywords:
-
- Protein tyrosine phosphorylation/dephosphorylation;
- Xenopus laevis fertilization;
- Egg activation;
- Genistein;
- Xyk;
- Xenopus tyrosine kinase;
- Na 3VO 4;
- sodium orthovanadate;
- DMSO;
- dimethylsulfoxide;
- DB;
- DeBoer's solution;
- SDS-PAGE;
- SDS-polyacrylamide gel electrophoresis;
- MAP kinase;
- mitogen-activated protein kinase