Academic Journal
Citrullination at the Nuclear Localization Signal of the Inhibitor of Growth 4 (ING4) Interferes With its Binding to Importin α3.
| Τίτλος: | Citrullination at the Nuclear Localization Signal of the Inhibitor of Growth 4 (ING4) Interferes With its Binding to Importin α3. |
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| Συγγραφείς: | Álvarez-Rodríguez MG; IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain., Vega S; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza 50018 Zaragoza, Spain., Hornos F; IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain., Fienco-Bacusoy A; Department of Physics, University of Calabria, 87036 Rende, Italy., Abian O; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza 50018 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBEREHD), 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza 50009 Zaragoza, Spain., Velazquez-Campoy A; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza 50018 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBEREHD), 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza 50009 Zaragoza, Spain. Electronic address: adrianvc@unizar.es., Rizzuti B; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza 50018 Zaragoza, Spain; CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, 87036 Rende, Italy. Electronic address: bruno.rizzuti@cnr.it., Neira JL; IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza 50018 Zaragoza, Spain. Electronic address: jlneira@umh.es. |
| Πηγή: | Journal of molecular biology [J Mol Biol] 2026 Sep 01; Vol. 438 (17), pp. 169877. Date of Electronic Publication: 2026 May 21. |
| Τύπος έκδοσης: | Journal Article |
| Γλώσσα: | English |
| Στοιχεία περιοδικού: | Publisher: Elsevier Country of Publication: Netherlands NLM ID: 2985088R Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1089-8638 (Electronic) Linking ISSN: 00222836 NLM ISO Abbreviation: J Mol Biol Subsets: MEDLINE |
| Imprint Name(s): | Publication: Amsterdam : Elsevier Original Publication: 1959- : London : Academic Press |
| Ιατρικοί όροι (MeSH): | alpha Karyopherins*/metabolism , alpha Karyopherins*/chemistry , Nuclear Localization Signals*/metabolism , Homeodomain Proteins*/metabolism , Homeodomain Proteins*/chemistry , Homeodomain Proteins*/genetics , Citrullination*, Citrulline/metabolism ; Protein-Arginine Deiminase Type 4/metabolism ; Arginine/metabolism ; Humans ; Protein Binding ; Cell Cycle Proteins ; Tumor Suppressor Proteins |
| Περίληψη: | The inhibitor of growth 4 (ING4) acts as a tumor suppressor regulating chromatin structure. Due to this nuclear function, ING4 has a nuclear localization signal (NLS), which is recognized by the cellular translocation machinery ‒ mainly formed by proteins named importins, which include the isoform importin α3 (Impα3) ‒ to allow movement through the nuclear membrane. Peptidyl arginine iminohydrolases (PADIs) are enzymes involved in the posttranslational modification of arginine to citrulline. PADI4, one of the five isoforms of PADI in humans, citrullinates ING4 at the NLS region. We studied in vitro and in silico how the different degrees of citrullination affected binding of the NLS of ING4 to PADI4, Impα3 and its truncated species (ΔImpα3), lacking the importin binding domain, by using several biophysical techniques and molecular simulations. To that end, we synthesized eight peptides encompassing the NLS of ING4 (residues 130-152), with single, double and triple citrulline replacements at Arg132, Arg142 and Arg144. The peptides were monomeric and disordered, as tested by DOSY, 1D- and 2D-1H NMR experiments. All the peptides were capable of binding to PADI4 with low micromolar affinities, but their affinity decreased as the fraction of citrullination increased. Moreover, all peptides could bind to both importin species with affinities in the low micromolar range, and their affinities were also dependent on the citrullination degree. The peptides targeted the canonical NLS binding site for cargo proteins of both importin species. These findings suggest that: (i) citrullination at the NLS might interfere with ING4 nuclear translocation; and (ii) successive citrullination at the NLS affected binding to PADI4. (Copyright © 2026 The Author(s). Published by Elsevier Ltd.. All rights reserved.) |
| Competing Interests: | Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. |
| Contributed Indexing: | Keywords: PADI proteins; calorimetry; fluorescence; importin proteins; nuclear localization signal |
| Substance Nomenclature: | 0 (alpha Karyopherins) 0 (Nuclear Localization Signals) 0 (ING4 protein, human) 0 (Homeodomain Proteins) 29VT07BGDA (Citrulline) EC 3.5.3.15 (Protein-Arginine Deiminase Type 4) EC 3.5.3.15 (PADI4 protein, human) 94ZLA3W45F (Arginine) 0 (Cell Cycle Proteins) 0 (Tumor Suppressor Proteins) |
| Entry Date(s): | Date Created: 20260522 Date Completed: 20260611 Latest Revision: 20260611 |
| Update Code: | 20260612 |
| DOI: | 10.1016/j.jmb.2026.169877 |
| PMID: | 42173437 |
| Βάση Δεδομένων: | MEDLINE |
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