Autophagy-related protein

Function

Autophagy-related proteins (Atg) function in autophagosome formation from the pre-autophagosomal structure (PAS). The phagosomes perform protein degradation under starvation. Autophagy is the process of forming a vacuole around proteins or nucleic acids destined to be broken down. This vacuole is a double membrane enclosure called phagophore. Atgs have non-autophagic functions as well as they are involved in cell survival and apoptosis.^[1] So far 34 Atgs have been identified in yeast.

Atg1, 6, 14 are involved in the formation of the phagophore.
Atg3 catalyzes the conjugation of Atg8 and phosphatidylethanolamine. This conjugation is essential for autophagosome formation.
Atg4, 5, 7, 10, 16 are involved in the maturation of the phagophore.
Atg8 is structurally similar to ubiquitin. It is a targeting factor in cytoplasm-to-vacuole transport of proteins such as aminopeptidase and a-mannosidase. Microtubule-associated protein light chain 3 LC3 is a mammalian Atg8.
Atg12 is involved in the elongation of the phagophore.
Atg13, 17 are PAS scaffold proteins.
Atg101 is believed to protect Atg13 from proteasomal degradation.

Structural highlights

(PDB code 3vh3). in yeast Atg7 C-terminal domain.^[2]

3D Structures of autophagy-related protein

Autophagy-related protein 3D structures

Yeast Atg7 C terminal (green) complex with Atg8 (magenta) and Zn+2 ion (grey) (PDB code 3vh3)

Drag the structure with the mouse to rotate

ReferencesReferences

↑ Shibutani ST, Saitoh T, Nowag H, Munz C, Yoshimori T. Autophagy and autophagy-related proteins in the immune system. Nat Immunol. 2015 Sep 18;16(10):1014-24. doi: 10.1038/ni.3273. PMID:26382870 doi:http://dx.doi.org/10.1038/ni.3273
↑ Noda NN, Satoo K, Fujioka Y, Kumeta H, Ogura K, Nakatogawa H, Ohsumi Y, Inagaki F. Structural basis of Atg8 activation by a homodimeric E1, Atg7. Mol Cell. 2011 Nov 4;44(3):462-75. PMID:22055191 doi:10.1016/j.molcel.2011.08.035

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Michal Harel, Alexander Berchansky, Joel L. Sussman, Jaime Prilusky

[1] Shibutani ST, Saitoh T, Nowag H, Munz C, Yoshimori T. Autophagy and autophagy-related proteins in the immune system. Nat Immunol. 2015 Sep 18;16(10):1014-24. doi: 10.1038/ni.3273. PMID:26382870 doi:http://dx.doi.org/10.1038/ni.3273

[2] Noda NN, Satoo K, Fujioka Y, Kumeta H, Ogura K, Nakatogawa H, Ohsumi Y, Inagaki F. Structural basis of Atg8 activation by a homodimeric E1, Atg7. Mol Cell. 2011 Nov 4;44(3):462-75. PMID:22055191 doi:10.1016/j.molcel.2011.08.035

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