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PLoS One January 1, 2013; 8 (3): e57345.

Solution structure of the QUA1 dimerization domain of pXqua, the Xenopus ortholog of Quaking.

Ali M , Broadhurst RW .

The STAR protein family member Quaking is essential for early development in vertebrates. For example, in oligodendrocyte cells it regulates the splicing, localization, translation and lifetime of a set of mRNAs that code for crucial components of myelin. The Quaking protein contains three contiguous conserved regions: a QUA1 oligomerization element, followed by a single-stranded RNA binding motif comprising the KH and QUA2 domains. An embryonic lethal point mutation in the QUA1 domain, E48G, is known to affect both the aggregation state and RNA-binding properties of the murine Quaking ortholog (QKI). Here we report the NMR solution structure of the QUA1 domain from the Xenopus laevis Quaking ortholog (pXqua), which forms a dimer composed of two perpendicularly docked α-helical hairpin motifs. Size exclusion chromatography studies of a range of mutants demonstrate that the dimeric state of the pXqua QUA1 domain is stabilized by a network of interactions between side-chains, with significant roles played by an intra-molecular hydrogen bond between Y41 and E72 (the counterpart to QKI E48) and an inter-protomer salt bridge between E72 and R67. These results are compared with recent structural and mutagenesis studies of QUA1 domains from the STAR family members QKI, GLD-1 and Sam68.

PubMed ID: 23520467
PMC ID: PMC3592866
Article link: PLoS One
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: khdrbs1 pc.1 qki

Article Images: [+] show captions
References [+] :
Aberg, Human QKI, a potential regulator of mRNA expression of human oligodendrocyte-related genes involved in schizophrenia. 2006, Pubmed