Identification of a novel nucleophosmin-interaction motif in the tumor suppressor p14arf.

Abstract

The tumor suppressor p14arf interacts, in response to oncogenic signals, with the p53 E3-ubiquitin ligase HDM2, thereby resulting in p53 stabilization and activation. In addition, it also exerts tumor-suppressive functions in p53-independent contexts. The activities of p14arf are regulated by the nucleolar chaperone nucleophosmin (NPM1), which controls its levels and cellular localization. In acute myeloid leukemia with mutations in the NPM1 gene, mutated NPM1 aberrantly translocates in the cytosol carrying with itself p14arf that is subsequently degraded, thus impairing the p14arf-HDM2-p53 axis. In this work we investigated the complex between these two proteins by means of NMR and other techniques. We identified a novel NPM1-interacting motif in the C-terminal region of p14arf, which corresponds to its predicted nucleolar localization signal. This motif recognizes a specific region of the NPM1 N-terminal domain and, upon binding, the two proteins form soluble high molecular weight complexes. By NMR, we identified critical residues on both proteins involved in the interaction. Collectively, our data provide a structural framework to rationalize the overall assembly of the p14arf-NPM1 supramolecular complexes. A number of p14arf cancer-associated mutations cluster in this motif and their effect on the interaction with NPM1 was also analyzed.

• Authors: Enrico Luchinat, Sara Chiarella, Mimma Franceschini, Adele Di Matteo, Maurizio Brunori, Lucia Banci, Luca Federici
• Journal: The FEBS journal (FEBS J) Vol. 285 Issue 5 Pg. 832-847 (03 2018) ISSN: 1742-4658 [Electronic] England
• PMID: 29283500 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2017 Federation of European Biochemical Societies.

Chemical References

• NPM1 protein, human
• Neoplasm Proteins
• Npm1 protein, mouse
• Nuclear Proteins
• Protein Aggregates
• Recombinant Fusion Proteins
• Tumor Suppressor Protein p14ARF
• Nucleophosmin

Topics

• Amino Acid Motifs
• Amino Acid Sequence
• Animals
• Humans
• Leukemia, Myeloid, Acute (genetics, metabolism)
• Mice
• Models, Molecular
• Molecular Targeted Therapy
• Mutation
• Neoplasm Proteins (chemistry, genetics, physiology)
• Neoplasms (drug therapy, genetics, metabolism)
• Nuclear Magnetic Resonance, Biomolecular
• Nuclear Proteins (chemistry, genetics, physiology)
• Nucleophosmin
• Protein Aggregates
• Protein Conformation
• Protein Interaction Domains and Motifs
• Protein Interaction Mapping
• Recombinant Fusion Proteins (chemistry)
• Sequence Alignment
• Sequence Deletion
• Sequence Homology, Amino Acid
• Spectrometry, Fluorescence
• Tumor Suppressor Protein p14ARF (chemistry, genetics, physiology)