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EMBO J. 2010 Feb 3;29(3):606-18. doi: 10.1038/emboj.2009.369. Epub 2009 Dec 10.

Antagonism of Beclin 1-dependent autophagy by BCL-2 at the endoplasmic reticulum requires NAF-1.

Author information

1
Department of Biochemistry and Goodman Cancer Center, McGill University, Montreal, Quebec, Canada.

Abstract

In addition to mitochondria, BCL-2 is located at the endoplasmic reticulum (ER) where it is a constituent of several distinct complexes. Here, we identify the BCL-2-interacting protein at the ER, nutrient-deprivation autophagy factor-1 (NAF-1)-a bitopic integral membrane protein whose defective expression underlies the aetiology of the neurodegenerative disorder Wolfram syndrome 2 (WFS2). NAF-1 contains a two iron-two sulphur coordinating domain within its cytosolic region, which is necessary, but not sufficient for interaction with BCL-2. NAF-1 is displaced from BCL-2 by the ER-restricted BH3-only protein BIK and contributes to regulation of BIK-initiated autophagy, but not BIK-dependent activation of caspases. Similar to BCL-2, NAF-1 is found in association with the inositol 1,4,5-triphosphate receptor and is required for BCL-2-mediated depression of ER Ca(2+) stores. During nutrient deprivation as a physiological stimulus of autophagy, BCL-2 is known to function through inhibition of the autophagy effector and tumour suppressor Beclin 1. NAF-1 is required in this pathway for BCL-2 at the ER to functionally antagonize Beclin 1-dependent autophagy. Thus, NAF-1 is a BCL-2-associated co-factor that targets BCL-2 for antagonism of the autophagy pathway at the ER.

PMID:
20010695
PMCID:
PMC2830692
DOI:
10.1038/emboj.2009.369
[Indexed for MEDLINE]
Free PMC Article

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