Novel serine 176 phosphorylation of YBX1 activates NF-κB in colon cancer

Matthew Martin, Laiqing Hua, Benlian Wang, Han Wei, Lakshmi Prabhu, Antja Voy Hartley, Guanglong Jiang, Yunlong Liu, Tao Lu

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11 Scopus citations

Abstract

Y box protein 1 (YBX1) is a well known oncoprotein that has tumor-promoting functions. YBX1 is widely considered to be an attractive therapeutic target in cancer. To develop novel therapeutics to target YBX1, it is of great importance to understand how YBX1 is finely regulated in cancer. Previously, we have shown that YBX1 could function as a tumor promoter through phosphorylation of its Ser-165 residue, leading to the activation of the NF-κB signaling pathway (1). In this study, using mass spectrometry analysis, we discovered a distinct phosphorylation site, Ser-176, on YBX1. Overexpression of the YBX1-S176A (serine-to-alanine) mutant in either HEK293 cells or colon cancer HT29 cells showed dramatically reduced NF-κB-activating ability compared with that of WT-YBX1, confirming that Ser-176 phosphorylation is critical for the activation of NF-κB by YBX1. Importantly, the mutant of Ser-176 and the previously reported Ser-165 sites regulate distinct groups of NF-κB target genes, suggesting the unique and irreplaceable function of each of these two phosphorylated serine residues. Our important findings could provide a novel cancer therapy strategy by blocking either Ser-176 or Ser-165 phosphorylation or both of YBX1 in colon cancer.

Original languageEnglish (US)
Pages (from-to)3433-3444
Number of pages12
JournalJournal of Biological Chemistry
Volume292
Issue number8
DOIs
StatePublished - Feb 24 2017

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Martin, M., Hua, L., Wang, B., Wei, H., Prabhu, L., Hartley, A. V., Jiang, G., Liu, Y., & Lu, T. (2017). Novel serine 176 phosphorylation of YBX1 activates NF-κB in colon cancer. Journal of Biological Chemistry, 292(8), 3433-3444. https://doi.org/10.1074/jbc.M116.740258