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TMBIM3/GRINA is a novel unfolded protein response (UPR) target gene that controls apoptosis through the modulation of

D Rojas-Rivera1, R Armisén, A Colombo

  • 1Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile.

Cell Death and Differentiation
|January 14, 2012
PubMed

Insights

Transmembrane BAX inhibitor motif-containing 3 (TMBIM3/GRINA) regulates cell death during endoplasmic reticulum (ER) stress. TMBIM3/GRINA works with TMBIM6/BI-1 to control ER calcium and apoptosis, showing conserved roles in cell death regulation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Transmembrane BAX inhibitor motif-containing (TMBIM)-6 (BI-1) is an anti-apoptotic protein.
  • The TMBIM gene family is conserved but poorly characterized.
  • Endoplasmic reticulum (ER) stress is implicated in various cellular dysfunctions.

Purpose of the Study:

  • To investigate the function of TMBIM3/GRINA in ER stress-induced cell death.
  • To explore the relationship between TMBIM3/GRINA, TMBIM6/BI-1, and ER calcium homeostasis.
  • To determine the in vivo role of TMBIM3/GRINA and TMBIM6/BI-1 in cell death regulation.

Main Methods:

  • Analysis of Tmbim3 mRNA levels in ER stress models.
  • Investigating TMBIM3/GRINA interactions with inositol trisphosphate receptors.
  • Loss-of-function studies in D. melanogaster and zebrafish embryos.

Main Results:

  • Tmbim3 mRNA is upregulated by ER stress via the PERK pathway.
  • TMBIM3/GRINA and TMBIM6/BI-1 synergize to modulate ER calcium and apoptosis.
  • TMBIM3/GRINA and TMBIM6/BI-1 exhibit synergistic anti-ER stress activity in vivo.
  • TMBIM3/GRINA is crucial for apoptosis control during zebrafish neuronal development and ER stress.

Conclusions:

  • TMBIM3/GRINA is a key regulator of ER stress-induced apoptosis.
  • TMBIM3/GRINA and TMBIM6/BI-1 form a functional complex at the ER membrane.
  • These findings reveal a conserved family of cell death regulators beyond the BCL-2 family.

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