The Geminin and Idas coiled coils preferentially form a heterodimer that inhibits Geminin function in DNA replication licensing

Caillat, Christophe, Pefani, Dafni-Eleftheria, Gillespie, Peter J., Taraviras, Stavros, Blow, J. Julian, Lygerou, Zoi and Perrakis, Anastassis (2013) The Geminin and Idas coiled coils preferentially form a heterodimer that inhibits Geminin function in DNA replication licensing. Journal of Biological Chemistry, 288 (44). pp. 31624-31634. ISSN 0021-9258

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Abstract

Geminin is an important regulator of proliferation and differentiation in metazoans, which predominantly inhibits the DNA replication licensing factor Cdt1, preventing genome over-replication. We show that Geminin preferentially forms stable coiled-coil heterodimers with its homologue, Idas. In contrast to Idas-Geminin heterodimers, Idas homodimers are thermodynamically unstable and are unlikely to exist as a stable macro-molecule under physiological conditions. The crystal structure of the homology regions of Idas in complex with Geminin showed a tight head-to-head heterodimeric coiled-coil. This Idas-Geminin heterodimer binds Cdt1 less strongly than Geminin-Geminin, still with high affinity (~30 nM), but with notably different thermodynamic properties. Consistently, in Xenopus egg extracts, Idas-Geminin is less active in licensing inhibition compared with a Geminin-Geminin homodimer. In human cultured cells, ectopic expression of Idas leads to limited over-replication, which is counteracted by Geminin co-expression. The properties of the Idas-Geminin complex suggest it as the functional form of Idas and provide a possible mechanism to modulate Geminin activity.

Item Type:	Article
Faculty \ School:
Depositing User:	LivePure Connector
Date Deposited:	10 Jun 2024 15:30
Last Modified:	10 Jun 2024 15:30
URI:	https://ueaeprints.uea.ac.uk/id/eprint/95466
DOI:	10.1074/jbc.M113.491928

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