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The endoplasmic reticulum stress-inducible protein Niban regulates eIF2alpha and S6K1/4E-BP1 phosphorylation

Guo Dong Sun1, Toshiyuki Kobayashi, Masaaki Abe

  • 1Department of Pathology and Oncology, Juntendo University School of Medicine, 2-1-1 Hongo, Tokyo 113-8421, Japan.

Biochemical and Biophysical Research Communications
|June 26, 2007
PubMed

Insights

Niban protein is crucial for regulating protein translation and cellular responses to endoplasmic reticulum (ER) stress. Its absence increases ER stress signaling and apoptosis, impacting cell death pathways.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • The Niban/NIBAN gene is linked to various cancers, including renal carcinomas.
  • Its expression suggests a role in carcinogenesis, but its function remains unknown.
  • Endoplasmic reticulum (ER) stress is implicated in cancer development and progression.

Purpose of the Study:

  • To investigate the functional role of Niban in the cellular response to ER stress.
  • To elucidate Niban's involvement in protein translation and cell death signaling.

Main Methods:

  • Generated Niban knockout mice to study in vivo function.
  • Treated cells with tunicamycin, an ER stress inducer.
  • Utilized NIBAN-specific interfering RNAs in HeLa cells.
  • Analyzed protein phosphorylation and apoptosis markers.

Main Results:

  • Niban/NIBAN expression is induced by ER stress.
  • Niban knockout cells exhibit increased eukaryotic translational initiation factor (eIF) 2alpha phosphorylation.
  • Niban deficiency leads to decreased phosphorylation of S6K1 and 4E-BP1.
  • Suppression of NIBAN promotes apoptosis in HeLa cells.

Conclusions:

  • Niban plays a significant role in the cellular response to ER stress.
  • Niban positively regulates protein translation machinery.
  • Niban modulates cell death signaling pathways by controlling translation.

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