» Articles » PMID: 16127448

Calcium Triggers Exit from Meiosis II by Targeting the APC/C Inhibitor XErp1 for Degradation

Overview
Journal Nature
Specialty Science
Date 2005 Aug 30
PMID 16127448
Citations 71
Authors
Affiliations
Soon will be listed here.
Abstract

Vertebrate eggs awaiting fertilization are arrested at metaphase of meiosis II by a biochemical activity termed cytostatic factor (CSF). This activity inhibits the anaphase-promoting complex/cyclosome (APC/C), a ubiquitin ligase that triggers anaphase onset and mitotic/meiotic exit by targeting securin and M-phase cyclins for destruction. On fertilization a transient rise in free intracellular calcium causes release from CSF arrest and thus APC/C activation. Although it has previously been shown that calcium induces the release of APC/C from CSF inhibition through calmodulin-dependent protein kinase II (CaMKII), the relevant substrates of this kinase have not been identified. Recently, we characterized XErp1 (Emi2), an inhibitor of the APC/C and key component of CSF activity in Xenopus egg extract. Here we show that calcium-activated CaMKII triggers exit from meiosis II by sensitizing the APC/C inhibitor XErp1 for polo-like kinase 1 (Plx1)-dependent degradation. Phosphorylation of XErp1 by CaMKII leads to the recruitment of Plx1 that in turn triggers the destruction of XErp1 by phosphorylating a site known to serve as a phosphorylation-dependent degradation signal. These results provide a molecular explanation for how the fertilization-induced calcium increase triggers exit from meiosis II.

Citing Articles

Positively charged specificity site in cyclin B1 is essential for mitotic fidelity.

Heinzle C, Hofler A, Yu J, Heid P, Kremer N, Schunk R Nat Commun. 2025; 16(1):853.

PMID: 39833154 PMC: 11747444. DOI: 10.1038/s41467-024-55669-x.


A phosphate-binding pocket in cyclin B3 is essential for XErp1/Emi2 degradation in meiosis I.

Schunk R, Halder M, Schafer M, Johannes E, Heim A, Boland A EMBO Rep. 2025; 26(3):768-790.

PMID: 39747666 PMC: 11811201. DOI: 10.1038/s44319-024-00347-8.


FBXO43 increases CCND1 stability to promote hepatocellular carcinoma cell proliferation and migration.

Li C, Zhang J, Wu W, Zhu Z, Li F, Wu D Front Oncol. 2023; 13:1138348.

PMID: 36937431 PMC: 10020529. DOI: 10.3389/fonc.2023.1138348.


Investigation of Signals and Transcription Factors for The Generation of Female Germ-Like Cells.

Ebrahimi S, Shams A, Maghami P, Hekmat A Cell J. 2022; 24(8):458-464.

PMID: 36093805 PMC: 9468721. DOI: 10.22074/cellj.2022.8303.


SCF Ligases and Their Functions in Oogenesis and Embryogenesis-Summary of the Most Important Findings throughout the Animal Kingdom.

Kinterova V, Kanka J, Bartkova A, Toralova T Cells. 2022; 11(2).

PMID: 35053348 PMC: 8774150. DOI: 10.3390/cells11020234.