Abstract
The inositol 1,4,5-trisphosphate receptor (IP3R) is a major regulator of apoptotic signaling. Through interactions with members of the Bcl-2 family of proteins, it drives calcium (Ca2+) transients from the endoplasmic reticulum (ER) to mitochondria, thereby establishing a functional and physical link between these organelles. Importantly, the IP3R also regulates autophagy, and in particular, its inhibition/depletion strongly induces macroautophagy. Here, we show that the IP3R antagonist xestospongin B induces autophagy by disrupting a molecular complex formed by the IP3 R and Beclin 1, an interaction that is increased or inhibited by overexpression or knockdown of Bcl-2, respectively. An effect of Beclin 1 on Ca2+ homeostasis was discarded as siRNA-mediated knockdown of Beclin 1 did not affect cytosolic or luminal ER Ca2+ levels. Xestospongin B- or starvation-induced autophagy was inhibited by overexpression of the IP3R ligand-binding domain, which coimmunoprecipitated with Beclin 1. These results identify IP3R as a new regulator of the Beclin 1 complex that may bridge signals converging on the ER and initial phagophore formation.
Original language | English |
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Pages (from-to) | 1006-1017 |
Number of pages | 12 |
Journal | Cell Death and Differentiation |
Volume | 16 |
Issue number | 7 |
DOIs | |
Publication status | Published - 2009 |
Bibliographical note
Funding Information:Acknowledgements. GK is supported by the Ligue Nationale contre le Cancer (équipe labellisée), European Commission (RIGHT, ChemoRes, Apop-Train, Apo-SYs), Agence Nationale pour la Recherche, Cancéropôle Ile-de-France and Institut National contre le Cancer (INCa). We thank the International Collaboration Program ECOS-CONICYT, project C08S01. JMV is supported by Fondation pour la Recherche Médicale and CONICYT. CO holds a PhD scholarship from CONICYT, Chile. OK is supported by EMBO. AWEJ is a Medical Research Council student. We also thank Michael R Duchen (University College London) for the use of confocal facility (Zeiss LSM 510 Meta) and discussions, as well as to Dr. Roger Y Tsien (University of California at San Diego) for the donation of ERD1.
Funding
Acknowledgements. GK is supported by the Ligue Nationale contre le Cancer (équipe labellisée), European Commission (RIGHT, ChemoRes, Apop-Train, Apo-SYs), Agence Nationale pour la Recherche, Cancéropôle Ile-de-France and Institut National contre le Cancer (INCa). We thank the International Collaboration Program ECOS-CONICYT, project C08S01. JMV is supported by Fondation pour la Recherche Médicale and CONICYT. CO holds a PhD scholarship from CONICYT, Chile. OK is supported by EMBO. AWEJ is a Medical Research Council student. We also thank Michael R Duchen (University College London) for the use of confocal facility (Zeiss LSM 510 Meta) and discussions, as well as to Dr. Roger Y Tsien (University of California at San Diego) for the donation of ERD1.
Funders | Funder number |
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Cancéropôle Ile-de-France | |
European Commission | |
Agence Nationale de la Recherche | |
Comisión Nacional de Investigación Científica y Tecnológica | |
Fondation pour la Recherche Médicale | |
EMBO | |
Ligue Contre le Cancer | |
Right to Care |
ASJC Scopus Subject Areas
- Molecular Biology
- Cell Biology