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Biochem J May 1, 2000; 347 Pt 3 653-60.
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Identification of a C-terminal cdc25 sequence required for promotion of germinal vesicle breakdown.

Powers EA , Thompson DP , Garner-Hamrick PA , He W , Yem AW , Bannow CA , Staples DJ , Waszak GA , Smith CW , Deibel MR , Fisher C .

Glutathione S-transferase (GST)-cdc25B(31-566) induced germinal vesicle breakdown (GVBD) when microinjected into Xenopus oocytes. Purified, N-terminally truncated forms of cdc25B did not induce GVBD, even though many had phosphatase activity and activated cdc2 in vitro. N-terminally truncated forms of cdc25B inhibited induction of GVBD by longer forms of the enzyme suggesting a direct interaction in vivo. cdc25B(356-556), but not cdc25B(364-529), inhibited GVBD induction by GST-cdc25B(31-566) suggesting that a region of cdc25B near to the C-terminus was responsible for the inhibition. To determine the region of peptide sequence that was inhibitory, cdc25B(356-556) was subjected to proteolysis with endoproteinase lys-C. Following a demonstration that the resulting peptide mixture inhibited GST-cdc25B-dependent GVBD, a series of peptides spanning amino acids at the C-terminus were synthesized. The peptide TRSWAGERSR inhibited GVBD induced by GST-cdc25B. An alanine scan of the peptide revealed residues critical for GVBD inhibition, and site-directed mutagenesis of the corresponding residues in GST-cdc25B(31-566) eliminated its ability to induce GVBD. These results demonstrate that a cdc25B C-terminal domain, involved in dominant-negative inhibition of GVBD-competent cdc25B, is required for induction of GVBD following microinjection into oocytes.

PubMed ID: 10769167
PMC ID: PMC1221000
Article link: Biochem J

Species referenced: Xenopus laevis
Genes referenced: cdc25b cdc25c cdk1 rasgrf1

References [+] :
Abeliovich, Reversible oxidative aggregation obstructs specific proteolytic cleavage of glutathione S-transferase fusion proteins. 1996, Pubmed