Anti-apoptotic BCL-2 binds to all three IP3R isoforms, thereby limiting the Ca2+-flux properties of IP3R

Related Experiment Video

Updated: Feb 19, 2026

Examining BCL-2 Family Function with Large Unilamellar Vesicles
08:35

Examining BCL-2 Family Function with Large Unilamellar Vesicles

Published on: October 5, 2012

8.4K

Ian de Ridder1, Claire Cauwelier1,2, Larry E Wagner Ii3

  • 1Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.

Open Biology
|February 17, 2026
PubMed

Insights

Anti-apoptotic B-cell lymphoma 2 (BCL-2) inhibits all three inositol 1,4,5-trisphosphate receptor (IP3R) isoforms, universally suppressing intracellular calcium (Ca2+) signaling. This finding clarifies BCL-2

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The anti-apoptotic protein B-cell lymphoma 2 (BCL-2) is known to regulate calcium (Ca2+) signaling.
  • Inositol 1,4,5-trisphosphate receptors (IP3Rs) are key mediators of intracellular Ca2+ release, existing as three isoforms.
  • The specific impact of BCL-2 on individual IP3R isoforms within native hetero-tetrameric channels remains largely uncharacterized.

Purpose of the Study:

  • To elucidate the precise effects of BCL-2 on each of the three IP3R isoforms.
  • To investigate the role of BCL-2 in modulating Ca2+ signaling mediated by homo-tetrameric IP3R channels.
  • To determine BCL-2's influence on mitochondrial Ca2+ uptake following IP3R-mediated Ca2+ release.

Main Methods:

  • Utilized HEK293 cells with triple-IP3R knockout, reconstituted with single IP3R isoforms.
  • Employed co-immunoprecipitation to confirm BCL-2 interaction with IP3R isoforms.
  • Performed live-cell Ca2+ imaging and TIRF microscopy with Ca2+-puff analysis to assess channel activity.

Main Results:

  • BCL-2 directly interacts with all three IP3R isoforms.
  • BCL-2 overexpression universally suppresses Ca2+ signals evoked by any IP3R isoform.
  • BCL-2 impairs mitochondrial Ca2+ uptake and reduces Ca2+ puff frequency without altering amplitude or duration.

Conclusions:

  • BCL-2 functions as a universal inhibitor of all three IP3R isoforms.
  • BCL-2 plays a critical role in fine-tuning intracellular Ca2+ dynamics for cell survival.
  • BCL-2's modulation of Ca2+ signaling presents a potential therapeutic target in cancer.
Keywords:
BCL-2 proteinsIP3 receptorscalcium signallingorganelles

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