Atg5, Autophagy related 5 or autophagy protein 5 (theoretical molecular weight 32 kDa), belongs to a group of core autophagy-related proteins first identified in yeast and later in eukaryotic cells. Atg proteins play essential roles in the process or macroautophagy. Atg5 is considered a core autophagy protein, for its role in the formation of the autophagosome, a double membrane vesicle which engulfs proteins and organelles for delivery to the lysosome and subsequent degradation (1). Atg5 participates in the process of phagophore elongation by interacting with the ubiquitin-like protein Atg12. Formation of the Atg12-Atg5 conjugate is dependent on the activities of Atg7 (E1 ubiquitin-activating like enzyme) and Atg10 (E2 ubiquitin-activating like enzyme). Non-covalent interaction between the Atg12-Atg5 conjugate and Atg16L1, allows for the formation of a large complex which associates with the nascent phagophore. The Atg16L1 complex dissociates from the autophagosome once it is fully formed (1,2).
In the context of its role in autophagy, Atg5 plays diverse physiologically relevant roles. For example, Atg5 together with Atg7 are required for adipogenesis (3). Recently, Atg5 has been implicated in the process of B-cell receptor polarization and antigen presentation (4). In addition to its role in autophagy, Atg5 is implicated in apoptotic cell death. Interaction of Atg5 with FADD (Fas-associated protein with death domain) is involved in cell death induced by IFN-gamma. A truncated form of Atg5, a 24kDa fragment, leads to cell death by interacting with Bcl-xl and inhibiting its anti-apoptotic activity (5). Other Atg5 interacting partners include interleukin-beta (IL-beta) converting enzyme and nucleotide binding oligomerization domain protein 1, which suggest that Atg5 may play other biologically relevant roles (3).
1. Yang, Z., & Klionsky, D. J. (2010). Mammalian autophagy: Core molecular machinery and signaling regulation. Current Opinion in Cell Biology. https://doi.org/10.1016/j.ceb.2009.11.014
2. Rubinsztein, D. C., Shpilka, T., & Elazar, Z. (2012). Mechanisms of autophagosome biogenesis. Current Biology. https://doi.org/10.1016/j.cub.2011.11.034
3. Subramani, S., & Malhotra, V. (2013). Non-autophagic roles of autophagy-related proteins. EMBO Reports. https://doi.org/10.1038/embor.2012.220
4. Arbogast, F., Arnold, J., Hammann, P., Kuhn, L., Chicher, J., Murera, D., Gros, F. (2019). ATG5 is required for B cell polarization and presentation of particulate antigens. Autophagy. https://doi.org/10.1080/15548627.2018.1516327
5. Luo, S., & Rubinsztein, D. C. (2007). Atg5 and Bcl-2 provide novel insights into the interplay between apoptosis and autophagy. Cell Death and Differentiation. https://doi.org/10.1038/sj.cdd.4402149
|Product By Gene ID
- APG5 (Autophagy 5, S. Cerevisiae)-Like
- ATG5 Autophagy Related 5 Homolog
- Autophagy Related 5
- ATG5 autophagy related 5 homolog (S. cerevisiae)
- Autophagy protein 5
- APG5 autophagy 5-like (S. cerevisiae)