Karyopherin-β2 Recognition of a PY-NLS Variant that Lacks the Proline-Tyrosine Motif

Michael Soniat, Yuh Min Chook

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Karyopherin-β2 or Transportin-1 binds proline-tyrosine nuclear localization signals (PY-NLSs) in its cargos. PY-NLSs are described by structural disorder, overall positive charge, and binding epitopes composed of an N-terminal hydrophobic or basic motif and a C-terminal R-X2-5P-Y motif. The N-terminal tail of histone H3 binds Kapβ2 with high affinity but does not contain a recognizable PY-NLS. The crystal structure of the Kapβ2-H3 tail shows residues 11–27 of H3 binding to the PY-NLS site of Kapβ2. H3 residues 11TGGKAPRK18 bind the site for PY-NLS Epitope 1 (N-terminal hydrophobic/basic motif), which is most important for Kapβ2-binding. H3 residue Arg26 occupies the PY-NLS Epitope 2 position (usually arginine of R-X2-5P-Y) but PY-NLS Epitope 3 (proline-tyrosine motif) is missing in the H3 tail. Histone H3 thus provides an example of a PY-NLS variant with no proline-tyrosine or homologous proline-hydrophobic motif. The H3 tail uses a very strong Epitope 1 to compensate for loss of the often-conserved proline-tyrosine epitope.

Original languageEnglish (US)
Pages (from-to)1802-1809
Number of pages8
Issue number10
StatePublished - Oct 4 2016


  • PY-NLS
  • histones
  • importin
  • karyopherin
  • nuclear import
  • nuclear localization signal, NLS

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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