2C1T

Structure of the Kap60p:Nup2 complex

Summary for 2C1T

• Entry DOI: 10.2210/pdb2c1t/pdb
• Related: 1BK5 1BK6 1EE4 1EE5 1UN0 1WA5 2C1M
• Descriptor: IMPORTIN ALPHA SUBUNIT, NUCLEOPORIN NUP2 (3 entities in total)
• Functional Keywords: protein transport/membrane protein, armadillo repeat, karyopherin recycling, nls release, nucear import, nuclear protein, nucleoporin, protein transport, nuclear transport-complex, nuclear pore complex, phosphorylation, translocation, protein transport-membrane protein complex
• Biological source: SACCHAROMYCES CEREVISIAE (BAKER'S YEAST); More
• Cellular location: Cytoplasm, perinuclear region: Q02821; Nucleus, nuclear pore complex: P32499
• Total number of polymer chains: 4
• Total formula weight: 112007.10

Authors

Matsuura, Y.,Stewart, M. (deposition date: 2005-09-20, release date: 2005-11-22, Last modification date: 2023-12-13)

Primary citation

Matsuura, Y.,Stewart, M.
Nup50/Npap60 Function in Nuclear Import Complex Disassembly and Importin Recycling
Embo J., 24:3681-, 2005

PubMed Abstract: Nuclear import of proteins containing classical nuclear localization signals (NLS) is mediated by the importin-alpha:beta complex that binds cargo in the cytoplasm and facilitates its passage through nuclear pores, after which nuclear RanGTP dissociates the import complex and the importins are recycled. In vertebrates, import is stimulated by nucleoporin Nup50, which has been proposed to accompany the import complex through nuclear pores. However, we show here that the Nup50 N-terminal domain actively displaces NLSs from importin-alpha, which would be more consistent with Nup50 functioning to coordinate import complex disassembly and importin recycling. The crystal structure of the importin-alpha:Nup50 complex shows that Nup50 binds at two sites on importin-alpha. One site overlaps the secondary NLS-binding site, whereas the second extends along the importin-alpha C-terminus. Mutagenesis indicates that interaction at both sites is required for Nup50 to displace NLSs. The Cse1p:Kap60p:RanGTP complex structure suggests how Nup50 is then displaced on formation of the importin-alpha export complex. These results provide a rationale for understanding the series of interactions that orchestrate the terminal steps of nuclear protein import.

PubMed: 16222336
DOI: 10.1038/SJ.EMBOJ.7600843

Experimental method

X-RAY DIFFRACTION (2.6 Å)