Open AccessTargeting Nuclear Import Shuttles, Importins/Karyopherins alpha by a Peptide Mimicking the NF κB1/p50 Nuclear Localization Sequence
Author(s) -
Zienkiewicz Jozef,
Armitage Amy,
Hawiger Jacek
Publication year - 2013
Publication title -
journal of the american heart association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.494
H-Index - 85
ISSN - 2047-9980
DOI - 10.1161/jaha.113.000386
Subject(s) - importin , nuclear transport , karyopherin , nuclear localization sequence , biology , microbiology and biotechnology , biochemistry , cell nucleus , gene
Background We recently reported that a bifunctional nuclear transport modifier ( NTM ), cSN 50.1 peptide, reduced atherosclerosis, plasma cholesterol, triglycerides, and glucose along with liver fat and inflammatory markers, in a murine model of familial hypercholesterolemia. We determined that cSN 50.1 improved lipid homeostasis by modulating nuclear transport of sterol regulatory element‐binding proteins through interaction with importin β. Previous studies established that cSN 50.1 and related NTM s also modulate nuclear transport of proinflammatory transcription factors mediated by binding of their nuclear localization sequences ( NLS s) to importins/karyopherins α. However, selectivity and specificity of NTM s for importins/karyopherins α were undetermined. Methods and Results We analyzed interaction of the NTM hydrophilic module, N50 peptide, derived from the NLS of NF κB1/p50, with endogenous human importins/karyopherins α to determine the mechanism of NTM modulation of importin α‐mediated nuclear transport. We show that N50 peptide forms stable complexes with multiple importins/karyopherins α. However, only interaction with importin α5 (Imp α5) displayed specific, high‐affinity binding. The 2:1 stoichiometry of the N50‐Imp α5 interaction ( K D 1 =73 nmol/L, K D 2 =140 nmol/L) indicated occupancy of both major and minor NLS binding pockets. Utilizing in silico 3‐dimensional (3‐D) docking models and comparative structural analysis, we identified a structural component of the Imp α5 major NLS binding pocket that may stabilize N50 binding. Imp α5 also displayed rapid stimulus‐induced turnover, which could influence its availability for nuclear transport during the inflammatory response. Conclusions These results provide direct evidence that N50 peptide selectively targets Imp α5, encouraging further refinement of NLS ‐derived peptides as new tools to modulate inflammatory disorders.