Nuclear localization signal recognition causes release of importin-α from aggregates in the cytosol

Piergiorgio Percipalle, P. Jonathan G. Butler, John T. Finch, David A. Jans, Daniela Rhodes

Research output: Contribution to journalArticle

Abstract

Importin-α is a cytosolic receptor that recognizes classical Nuclear Localization Signals (NLSs) and mediates import into the nucleus. We have used a number of methods to investigate the aggregation state of Xenopus importin-α both as a recombinant, purified protein and in cytosolic extracts. We have found that recombinant importin-α aggregates at a protein concentration similar to that estimated to be present in the Xenopus cytoplasm, and that the importin-α aggregation is relieved by NLS peptide binding, with the importin-α then binding the NLS as a monomer. We have also found that in HeLa cytosolic extracts, importin-α is present in an aggregated form. Similarly to the purified importin-α aggregation, NLS peptides relieve the aggregation of importin-α in the cytosol. These observations indicate that aggregation of importin-α in the cytosol may be an intrinsic property of the import receptor and may be functionally related to NLS binding. Our results suggest a novel mechanism for NLS recognition, whereby NLSs mediate disassembly of importin-α aggregates in the cytosol.

Original languageEnglish (US)
Pages (from-to)263-273
Number of pages11
JournalJournal of Molecular Biology
Volume292
Issue number2
DOIs
StatePublished - Sep 17 1999

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Karyopherins
Nuclear Localization Signals
Cytosol
Xenopus
Recombinant Proteins
Cytoplasm

Keywords

  • Aggregation
  • Cytosolic extract
  • Imrortin-α
  • Nuclear localization signal (NLS) recognition
  • Sedimentation analysis

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

Cite this

Nuclear localization signal recognition causes release of importin-α from aggregates in the cytosol. / Percipalle, Piergiorgio; Butler, P. Jonathan G.; Finch, John T.; Jans, David A.; Rhodes, Daniela.

In: Journal of Molecular Biology, Vol. 292, No. 2, 17.09.1999, p. 263-273.

Research output: Contribution to journalArticle

Percipalle, Piergiorgio ; Butler, P. Jonathan G. ; Finch, John T. ; Jans, David A. ; Rhodes, Daniela. / Nuclear localization signal recognition causes release of importin-α from aggregates in the cytosol. In: Journal of Molecular Biology. 1999 ; Vol. 292, No. 2. pp. 263-273.
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