2P8Q

Crystal Structure of human Importin beta bound to the Snurportin1 IBB-domain

Summary for 2P8Q

• Entry DOI: 10.2210/pdb2p8q/pdb
• Related: 1QGK 1UKL
• Descriptor: Importin beta-1 subunit, Snurportin-1 (3 entities in total)
• Functional Keywords: heat repeat, ibb-domain, importin, karyopherin, snurportin, protein transport
• Biological source: Homo sapiens (human); More
• Cellular location: Nucleus: Q14974; Cytoplasm: O95149
• Total number of polymer chains: 2
• Total formula weight: 102285.57

Authors

Mitrousis, G.,Cingolani, G. (deposition date: 2007-03-22, release date: 2008-01-22, Last modification date: 2023-08-30)

Primary citation

Mitrousis, G.,Olia, A.S.,Walker-Kopp, N.,Cingolani, G.
Molecular Basis for the Recognition of Snurportin 1 by Importin {beta}.
J.Biol.Chem., 283:7877-7884, 2008

PubMed Abstract: The nuclear import of uridine-rich ribonucleoproteins 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 study, we demonstrate that 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 importin alpha IBB (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 (K(d) approximately 2 nm) in an interaction that, in vitro, is displaced by RanGTP. We propose that in vivo the synergy of Nup153 and nuclear RanGTP promotes translocation of uridine-rich ribonucleoproteins into the nucleus.

PubMed: 18187419
DOI: 10.1074/jbc.M709093200

Experimental method

X-RAY DIFFRACTION (2.35 Å)