Correlation of CRM1-NES affinity with nuclear export activity

Szu Chin Fu, Ho Yee Joyce Fung, Tolga Caǧatay, Jordan Baumhardt, Yuh Min Chook

Research output: Contribution to journalArticle

3 Scopus citations


CRM1 (Exportin1/XPO1) exports hundreds of broadly functioning protein cargoes out of the cell nucleus by binding to their classical nuclear export signals (NESs). The 8- to 15-amino-acid-long NESs contain four to five hydrophobic residues and are highly diverse in both sequence and CRM1-bound structure. Here we examine the relationship between nuclear export activities of 24 different NES peptides in cells and their CRM1-NES affinities. We found that binding affinity and nuclear export activity are linearly correlated for NESs with dissociation constants (Kds) between tens of nanomolar to tens of micromolar. NESs with Kds outside this range have significantly reduced nuclear export activities. These include two unusually tight-binding peptides, one from the nonstructural protein 2 of murine minute virus (MVM NS2) and the other a mutant of the protein kinase A inhibitor (PKI) NES. The crystal structure of CRM1-bound MVM NS2NES suggests that extraordinarily tight CRM1 binding arises from intramolecular contacts within the NES that likely stabilizes the CRM1-bound conformation in free peptides. This mechanistic understanding led to the design of two novel peptide inhibitors that bind CRM1 with picomolar affinity.

Original languageEnglish (US)
Pages (from-to)2037-2044
Number of pages8
JournalMolecular Biology of the Cell
Issue number17
StatePublished - Aug 15 2018

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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