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Background
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Macroautophagy is the major inducible pathway for the general turnover of cytoplasmic constituents in eukaryotic cells, it is also responsible for the degradation of active cytoplasmic enzymes and organelles during nutrient starvation. Macroautophagy involves the formation of double-membrane bound autophagosomes which enclose the cytoplasmic constituent targeted for degradation in a membrane bound structure, which then fuse with the lysosome (or vacuole) releasing a single-membrane bound autophagic bodies which are then degraded within the lysosome (or vacuole). Beclin 1 plays a role in two fundamentally important cell biological pathways: autophagy and apoptosis. Beclin 1 has recently been identified as novel BH3-only protein, meaning that it carries one Bcl-2-homology-3 (BH3) domain. Beclin 1 interacts with anti-apoptotic multidomain proteins of the Bcl-2 family by virtue of its BH3 domain, an amphipathic alpha-helix that binds to the hydrophobic cleft of Bcl-2/Bcl-X(L). The BH3 domains of other BH3-only proteins such as Bad, as well as BH3-mimetic compounds such as ABT737, competitively disrupt the inhibitory interaction between Beclin 1 and Bcl-2/Bcl-X(L). This causes autophagy of mitochondria (mitophagy) but not of the endoplasmic reticulum (reticulophagy).
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Background
References
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- Erlich S, et al. Autophagy. 2007. 3(6):561.
- Maiuri MC, et al. EMBO J. 2007. 26(10):2527.
- Maiuri MC, et al. Autophagy. 2007. 3(4):374.
- Oberstein A, et al. J Biol Chem. 2007. 282(17):13123.
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