2p8q
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Crystal Structure of human Importin beta bound to the Snurportin1 IBB-domain
OverviewOverview
The nuclear import of uridine-rich ribonucleoproteins (U snRNPs) is, mediated by the transport adaptor snurportin 1 (SNP1). Similar to importin, alpha, SNP1 uses an N-terminal importin beta binding (sIBB) domain to, recruit the receptor importin beta and gain access to the nucleus. In this, paper, we demonstrate the sIBB-domain has a bipartite nature, which, contains two distinct binding determinants for importin beta. The first, determinant spans residues 25-65, and includes the previously identified, alphaIBB-region of homology. The second binding determinant encompasses, residues 1-24 and resembles region 1011-1035 of the nucleoporin 153, (Nup153). The two binding determinants synergize within the sIBB-domain to, confer a low nanomolar binding affinity for importin beta, (Kd ~2nM) in an, interaction that, in vitro, is displaced by RanGppNHp. We propose that in, vivo the synergy of Nup153 and nuclear RanGTP promotes translocation of U, snRNPs into the nucleus.
About this StructureAbout this Structure
2P8Q is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Molecular basis for the recognition of snurportin 1 by importin beta., Mitrousis G, Olia AS, Walker-Kopp N, Cingolani G, J Biol Chem. 2008 Jan 9;. PMID:18187419
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