Download MendeleyStructural Basis for Polyadenosine-RNA Binding by Nab2 Zn Fingers and Its Function in mRNA Nuclear Export.
Brockmann, C., Soucek, S., Kuhlmann, S.I., Mills-Lujan, K., Kelly, S.M., Yang, J.C., Iglesias, N., Stutz, F., Corbett, A.H., Neuhaus, D., Stewart, M.(2012) Structure 20: 1007-1018
- PubMed: 22560733
- DOI: https://doi.org/10.1016/j.str.2012.03.011
- Primary Citation of Related Structures:
2LHN - PubMed Abstract:
Polyadenylation regulation and efficient nuclear export of mature mRNPs both require the polyadenosine-RNA-binding protein, Nab2, which contains seven CCCH Zn fingers. We describe here the solution structure of fingers 5-7, which are necessary and sufficient for high-affinity polyadenosine-RNA binding, and identify key residues involved. These Zn fingers form a single structural unit. Structural coherence is lost in the RNA-binding compromised Nab2-C437S mutant, which also suppresses the rat8-2 allele of RNA helicase Dbp5. Structure-guided Nab2 variants indicate that dbp5(rat8-2) suppression is more closely linked to hyperadenylation and suppression of mutant alleles of the nuclear RNA export adaptor, Yra1, than to affinity for polyadenosine-RNA. These results indicate that, in addition to modulating polyA tail length, Nab2 has an unanticipated function associated with generating export-competent mRNPs, and that changes within fingers 5-7 lead to suboptimal assembly of mRNP export complexes that are more easily disassembled by Dbp5 upon reaching the cytoplasm.
Organizational Affiliation:
Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
