Structural analysis of the G-box domain of the microcephaly protein CPAP suggests a role in centriole architecture.
Bottom Line: Centrioles are evolutionarily conserved eukaryotic organelles composed of a protein scaffold surrounded by sets of microtubules organized with a 9-fold radial symmetry.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.
Affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.Show MeSH
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Mentions: Human CPAP (HsCPAP) is a 1338 amino acids protein with a glycine-rich C-terminal domain (G-box) (Figure 1A). Previous work showed that separate HsCPAP motifs bind tubulin heterodimers and destabilize microtubules (PN2-3) (Cormier et al., 2009; Hung et al., 2004) or bind and stabilize microtubules (A5N) (Hsu et al., 2008). PN2-3, A5N, and the G-box are the most conserved regions between HsCPAP and its functional orthologs in D. rerio, Drosophila melanogaster, and Caenorhabditis elegans (Gopalakrishnan et al., 2011; Kitagawa et al., 2011a; Tang et al., 2011). All four orthologs also feature a predicted ∼150–200 residue coiled coil adjacent to the G-box; in contrast, the three N-terminal coiled coils of HsCPAP are not universally predicted, and they are presumed to be of low stability or unstructured as judged by their short length and biophysical properties (Cormier et al., 2009).
Affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.