Structural analysis of the G-box domain of the microcephaly protein CPAP suggests a role in centriole architecture.

Centrioles are evolutionarily conserved eukaryotic organelles composed of a protein scaffold surrounded by sets of microtubules organized with a 9-fold radial symmetry. CPAP, a centriolar protein essential for microtubule recruitment, features a C-terminal domain of unknown structure, the G-box. A missense mutation in the G-box reduces affinity for the centriolar shuttling protein STIL and causes primary microcephaly. Here, we characterize the molecular architecture of CPAP and determine the G-box structure alone and in complex with a STIL fragment. The G-box comprises a single elongated β sheet capable of forming supramolecular assemblies. Structural and biophysical studies highlight the conserved nature of the CPAP-STIL complex. We propose that CPAP acts as a horizontal "strut" that joins the centriolar scaffold with microtubules, whereas G-box domains form perpendicular connections. Copyright © 2013 Elsevier Ltd. All rights reserved.

Citation

Georgios N Hatzopoulos, Michèle C Erat, Erin Cutts, Kacper B Rogala, Leanne M Slater, Philip J Stansfeld, Ioannis Vakonakis. Structural analysis of the G-box domain of the microcephaly protein CPAP suggests a role in centriole architecture. Structure (London, England : 1993). 2013 Nov 05;21(11):2069-77

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PMID: 24076405

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