Title: Correlation of CRM1-NES affinity with nuclear export activity

Abstract

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 (K_ds) between tens of nanomolar to tens of micromolar. NESs with K_ds 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 NS2^NES 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.

Authors:

Fu, Szu-Chin ^[1]; Fung, Ho Joyce ^[1]; Cağatay, Tolga ^[1]; Baumhardt, Jordan ^[1]; Chook, Yuh Min ^[1]

---

+ Show Author Affiliations

1. Univ. of Texas Southwestern Medical Center, Dallas, TX (United States)

Publication Date:

Wed Aug 15 00:00:00 EDT 2018

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)

Sponsoring Org.:

USDOE; Cancer Prevention Research Institute of Texas; National Institutes of Health (NIH); Welch Foundation

OSTI Identifier:

1570748

Grant/Contract Number:  

RP150053; RP170170; RP180410; R01 GM069909; I-1532

Resource Type:

Accepted Manuscript

Journal Name:

Molecular Biology of the Cell

Additional Journal Information:

Journal Volume: 29; Journal Issue: 17; Journal ID: ISSN 1059-1524

Publisher:

American Society for Cell Biology

Country of Publication:

United States

Language:

ENGLISH

Subject:

59 BASIC BIOLOGICAL SCIENCES