Co-relation with novel phosphorylation sites of IκBα and necroptosis in breast cancer cells

Sung Hoon Choi, Hee Sub Yoon, Shin Ae Yoo, Sung Ho Yun, Joo Hee Park, Eun Hee Han, Sung Gil Chi, Young Ho Chung

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Background: Phosphorylation of NF-kappaB inhibitor alpha (IκBα) is key to regulation of NF-κB transcription factor activity in the cell. Several sites of IκBα phosphorylation by members of the IκB kinase family have been identified, but phosphorylation of the protein by other kinases remains poorly understood. We investigated a new phosphorylation site on IκBα and identified its biological function in breast cancer cells. Methods: Previously, we observed that aurora kinase (AURK) binds IκBα in the cell. To identify the domains of IκBα essential for phosphorylation by AURK, we performed kinase assays with a series of IκBα truncation mutants. AURK significantly promoted activation of IκBα at serine 32 but not serine 36; by contrast, IκB kinase (IKK) family proteins activated both of these residues. We also confirmed phosphorylation of IκBα by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) and nano-liquid chromatography hybrid quadrupole orbitrap mass spectrometer (nanoLC-MS/MS; Q-Exactive). Results: We identified two novel sites of serine phosphorylation, S63 and S262. Alanine substitution of S63 and S262 (S63A and S262A) of IκBα inhibited proliferation and suppressed p65 transcription activity. In addition, S63A and/or S262A of IκBα regulated apoptotic and necroptotic effects in breast cancer cells. Conclusions: Phosphorylation of IκBα by AURK at novel sites is related to the apoptosis and necroptosis pathways in breast cancer cells.

Original languageEnglish
Article number596
JournalBMC Cancer
Issue number1
Publication statusPublished - 2021 Dec

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).


  • Breast cancer
  • IκBα
  • Necroptosis
  • New phospho-site

ASJC Scopus subject areas

  • Oncology
  • Genetics
  • Cancer Research


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