| Structural highlights
Function
ATG40_YEAST Acts as a receptor for reticulophagy. Directs autophagic sequestration of folded tubules/sheets derived from the cortical endoplasmic reticulum (cER) and the cytoplasmic endoplasmic reticulum (cytoER) into autophagosomes. Is not required for the cytoplasm-to-vacuole targeting pathway, mitophagy, pexophagy, and non-selective autophagy.[1] 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.[2] [3] [4] [5] [6] [7] [8] [9] [10]
Publication Abstract from PubMed
The endoplasmic reticulum (ER) is selectively degraded by autophagy (ER-phagy) through proteins called ER-phagy receptors. In Saccharomyces cerevisiae, Atg40 acts as an ER-phagy receptor to sequester ER fragments into autophagosomes by binding Atg8 on forming autophagosomal membranes. During ER-phagy, parts of the ER are morphologically rearranged, fragmented, and loaded into autophagosomes, but the mechanism remains poorly understood. Here we find that Atg40 molecules assemble in the ER membrane concurrently with autophagosome formation via multivalent interaction with Atg8. Atg8-mediated super-assembly of Atg40 generates highly-curved ER regions, depending on its reticulon-like domain, and supports packing of these regions into autophagosomes. Moreover, tight binding of Atg40 to Atg8 is achieved by a short helix C-terminal to the Atg8-family interacting motif, and this feature is also observed for mammalian ER-phagy receptors. Thus, this study significantly advances our understanding of the mechanisms of ER-phagy and also provides insights into organelle fragmentation in selective autophagy of other organelles.
Super-assembly of ER-phagy receptor Atg40 induces local ER remodeling at contacts with forming autophagosomal membranes.,Mochida K, Yamasaki A, Matoba K, Kirisako H, Noda NN, Nakatogawa H Nat Commun. 2020 Jul 3;11(1):3306. doi: 10.1038/s41467-020-17163-y. PMID:32620754[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Mochida K, Oikawa Y, Kimura Y, Kirisako H, Hirano H, Ohsumi Y, Nakatogawa H. Receptor-mediated selective autophagy degrades the endoplasmic reticulum and the nucleus. Nature. 2015 Jun 18;522(7556):359-62. doi: 10.1038/nature14506. Epub 2015 Jun 3. PMID:26040717 doi:http://dx.doi.org/10.1038/nature14506
- ↑ 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
- ↑ Mochida K, Yamasaki A, Matoba K, Kirisako H, Noda NN, Nakatogawa H. Super-assembly of ER-phagy receptor Atg40 induces local ER remodeling at contacts with forming autophagosomal membranes. Nat Commun. 2020 Jul 3;11(1):3306. doi: 10.1038/s41467-020-17163-y. PMID:32620754 doi:http://dx.doi.org/10.1038/s41467-020-17163-y
|
