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Updated: Jun 24, 2026

Study of Protein-protein Interactions in Autophagy Research
14:08

Study of Protein-protein Interactions in Autophagy Research

Published on: September 9, 2017

The inositol 1,4,5-trisphosphate receptor regulates autophagy through its interaction with Beclin 1

J M Vicencio1, C Ortiz, A Criollo

  • 1INSERM, U848, F-94805 Villejuif, France.

Cell Death and Differentiation
|March 28, 2009
PubMed

Insights

The inositol 1,4,5-trisphosphate receptor (IP(3)R) regulates autophagy by interacting with Beclin 1. Disrupting this complex with xestospongin B induces autophagy, linking ER signals to phagophore formation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Autophagy Research

Background:

  • The inositol 1,4,5-trisphosphate receptor (IP(3)R) is crucial for calcium signaling and apoptosis.
  • IP(3)R links the endoplasmic reticulum (ER) and mitochondria, influencing cellular processes.
  • IP(3)R also plays a role in regulating autophagy, with its inhibition inducing macroautophagy.

Purpose of the Study:

  • To investigate the role of IP(3)R in autophagy regulation.
  • To elucidate the molecular mechanism by which IP(3)R influences autophagy, particularly concerning Beclin 1.

Main Methods:

  • Utilized the IP(3)R antagonist xestospongin B to induce autophagy.
  • Examined the interaction between IP(3)R and Beclin 1 using co-immunoprecipitation.
  • Assessed the impact of Bcl-2 on the IP(3)R-Beclin 1 complex.
  • Investigated the effect of Beclin 1 knockdown on calcium homeostasis.
  • Studied the influence of IP(3)R ligand-binding domain overexpression on autophagy.

Main Results:

  • Xestospongin B induces autophagy by disrupting the IP(3)R-Beclin 1 complex.
  • Bcl-2 overexpression enhances, while knockdown inhibits, the IP(3)R-Beclin 1 interaction.
  • Beclin 1 knockdown does not affect ER or cytosolic calcium levels, ruling out its role in calcium homeostasis.
  • Overexpression of the IP(3)R ligand-binding domain inhibits xestospongin B- or starvation-induced autophagy.

Conclusions:

  • Identifies IP(3)R as a novel regulator of the Beclin 1 complex, a key player in autophagy initiation.
  • Suggests that IP(3)R acts as a bridge, connecting signals at the ER to the early stages of phagophore formation.
  • Highlights the intricate relationship between calcium signaling, ER-mitochondria crosstalk, and autophagy control.

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