4bry | pdb_00004bry
The Idas:Geminin heterodimeric parallel coiled-coil
Structural highlights
Function[GEMI_HUMAN] Inhibits DNA replication by preventing the incorporation of MCM complex into pre-replication complex (pre-RC). It is degraded during the mitotic phase of the cell cycle. Its destruction at the metaphase-anaphase transition permits replication in the succeeding cell cycle.[1] [2] [3] Inhibits the transcriptional activity of a subset of Hox proteins, enrolling them in cell proliferative control.[4] [5] [6] [MCIN_HUMAN] Transcription regulator required for multiciliate cell differentiation. Acts by promoting transcription of genes required for multiciliate cell formation. Probably acts in a multiprotein complex (By similarity). Plays a role in mitotic cell cycle progression by promoting cell cycle exit. Publication Abstract from PubMedGeminin 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 macromolecule 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 (~30nM), but with notably different thermodynamic properties. Consistently, in Xenopus egg extracts, Idas:Geminin is less active in licensing inhibition compared to 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. The Geminin and Idas coiled coils preferentially form a heterodimer that inhibits Geminin function in DNA replication licensing.,Caillat C, Pefani ED, Gillespie PJ, Taraviras S, Blow JJ, Lygerou Z, Perrakis A J Biol Chem. 2013 Oct 2. PMID:24064211[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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