Quaternary structure of the human Cdt1-Geminin complex regulates DNA replication licensing

V. De Marco, P. J. Gillespie, A. Li, N. Karantzelis, E. Christodoulou, R. Klompmaker, S. van Gerwen, A. Fish, M. V. Petoukhov, M. S. Iliou, Z. Lygerou, R. H. Medema, J.J. Blow, D. I. Svergun, S. Taraviras, A. Perrakis

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    54 Citations (Scopus)

    Abstract

    All organisms need to ensure that no DNA segments are rereplicated in a single cell cycle. Eukaryotes achieve this through a process called origin licensing, which involves tight spatiotemporal control of the assembly of prereplicative complexes (pre-RCs) onto chromatin. Cdt1 is a key component and crucial regulator of pre-RC assembly. In higher eukaryotes, timely inhibition of Cdt1 by Geminin is essential to prevent DNA rereplication. Here, we address the mechanism of DNA licensing inhibition by Geminin, by combining X-ray crystallography, small-angle X-ray scattering, and functional studies in Xenopus and mammalian cells. Our findings show that the Cdt1: Geminin complex can exist in two distinct forms, a "permissive" heterotrimer and an "inhibitory" heterohexamer. Specific Cdt1 residues, buried in the heterohexamer, are important for licensing. We postulate that the transition between the heterotrimer and the heterohexamer represents a molecular switch between licensing-competent and licensing-defective states.

    Original languageEnglish
    Pages (from-to)19807-19812
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume106
    Issue number47
    DOIs
    Publication statusPublished - 2009

    Keywords

    • solution structure
    • X-ray structure
    • pre-RC
    • cell cycle
    • XENOPUS EGG EXTRACTS
    • CELL-CYCLE
    • RE-REPLICATION
    • FACTOR CDT1
    • PREVENTS REREPLICATION
    • NUCLEAR IMPORT
    • S-PHASE
    • GEMININ
    • INHIBITION
    • DESTRUCTION

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