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6aag

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Crystal structure of budding yeast Atg8 complexed with the helical AIM of Hfl1.

Structural highlights

6aag is a 7 chain structure with sequence from Saccharomyces cerevisiae S288C and Saccharomyces cerevisiae YJM789. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.445Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

TM184_YEAST ATG8_YEAST Involved in cytoplasm to vacuole transport (Cvt) vesicles and autophagosomes formation. With ATG4, may mediate the delivery of the vesicles and autophagosomes to the vacuole via the microtubule cytoskeleton. Participates also in membrane fusion events that take place in the early secretory pathway.^[1] ^[2] ^[3] ^[4] ^[5] ^[6] ^[7] ^[8] ^[9]

Publication Abstract from PubMed

The ubiquitin-like protein Atg8, in its lipidated form, plays central roles in autophagy. Yet, remarkably, Atg8 also carries out lipidation-independent functions in non-autophagic processes. How Atg8 performs its moonlighting roles is unclear. Here we report that in the fission yeast Schizosaccharomyces pombe and the budding yeast Saccharomyces cerevisiae, the lipidation-independent roles of Atg8 in maintaining normal morphology and functions of the vacuole require its interaction with a vacuole membrane protein Hfl1 (homolog of human TMEM184 proteins). Crystal structures revealed that the Atg8-Hfl1 interaction is not mediated by the typical Atg8-family-interacting motif (AIM) that forms an intermolecular beta-sheet with Atg8. Instead, the Atg8-binding regions in Hfl1 proteins adopt a helical conformation, thus representing a new type of AIMs (termed helical AIMs here). These results deepen our understanding of both the functional versatility of Atg8 and the mechanistic diversity of Atg8 binding.

Lipidation-independent vacuolar functions of Atg8 rely on its noncanonical interaction with a vacuole membrane protein.,Liu XM, Yamasaki A, Du XM, Coffman VC, Ohsumi Y, Nakatogawa H, Wu JQ, Noda NN, Du LL Elife. 2018 Nov 19;7. pii: 41237. doi: 10.7554/eLife.41237. PMID:30451685^[10]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Tsukada M, Ohsumi Y. Isolation and characterization of autophagy-defective mutants of Saccharomyces cerevisiae. FEBS Lett. 1993 Oct 25;333(1-2):169-74. PMID:8224160
↑ Harding TM, Morano KA, Scott SV, Klionsky DJ. Isolation and characterization of yeast mutants in the cytoplasm to vacuole protein targeting pathway. J Cell Biol. 1995 Nov;131(3):591-602. PMID:7593182
↑ Lang T, Schaeffeler E, Bernreuther D, Bredschneider M, Wolf DH, Thumm M. Aut2p and Aut7p, two novel microtubule-associated proteins are essential for delivery of autophagic vesicles to the vacuole. EMBO J. 1998 Jul 1;17(13):3597-607. PMID:9649430 doi:10.1093/emboj/17.13.3597
↑ Kirisako T, Baba M, Ishihara N, Miyazawa K, Ohsumi M, Yoshimori T, Noda T, Ohsumi Y. Formation process of autophagosome is traced with Apg8/Aut7p in yeast. J Cell Biol. 1999 Oct 18;147(2):435-46. PMID:10525546
↑ Huang WP, Scott SV, Kim J, Klionsky DJ. The itinerary of a vesicle component, Aut7p/Cvt5p, terminates in the yeast vacuole via the autophagy/Cvt pathways. J Biol Chem. 2000 Feb 25;275(8):5845-51. PMID:10681575
↑ Legesse-Miller A, Sagiv Y, Glozman R, Elazar Z. Aut7p, a soluble autophagic factor, participates in multiple membrane trafficking processes. J Biol Chem. 2000 Oct 20;275(42):32966-73. PMID:10837468 doi:10.1074/jbc.M000917200
↑ Kirisako T, Ichimura Y, Okada H, Kabeya Y, Mizushima N, Yoshimori T, Ohsumi M, Takao T, Noda T, Ohsumi Y. The reversible modification regulates the membrane-binding state of Apg8/Aut7 essential for autophagy and the cytoplasm to vacuole targeting pathway. J Cell Biol. 2000 Oct 16;151(2):263-76. PMID:11038174
↑ Ichimura Y, Kirisako T, Takao T, Satomi Y, Shimonishi Y, Ishihara N, Mizushima N, Tanida I, Kominami E, Ohsumi M, Noda T, Ohsumi Y. A ubiquitin-like system mediates protein lipidation. Nature. 2000 Nov 23;408(6811):488-92. PMID:11100732 doi:10.1038/35044114
↑ Kim J, Huang WP, Klionsky DJ. Membrane recruitment of Aut7p in the autophagy and cytoplasm to vacuole targeting pathways requires Aut1p, Aut2p, and the autophagy conjugation complex. J Cell Biol. 2001 Jan 8;152(1):51-64. PMID:11149920
↑ Liu XM, Yamasaki A, Du XM, Coffman VC, Ohsumi Y, Nakatogawa H, Wu JQ, Noda NN, Du LL. Lipidation-independent vacuolar functions of Atg8 rely on its noncanonical interaction with a vacuole membrane protein. Elife. 2018 Nov 19;7. pii: 41237. doi: 10.7554/eLife.41237. PMID:30451685 doi:http://dx.doi.org/10.7554/eLife.41237