ATG20/YDL113C Summary Help

Standard Name ATG20 1
Systematic Name YDL113C
Alias SNX42 2 , CVT20 3
Feature Type ORF, Verified
Description Sorting nexin family member; required for the cytoplasm-to-vacuole targeting (Cvt) pathway and for endosomal sorting; has a Phox homology domain that binds phosphatidylinositol-3-phosphate; interacts with Snx4p; potential Cdc28p substrate (2, 3, 4 and see Summary Paragraph)
Name Description AuTophaGy related 1
Chromosomal Location
ChrIV:258555 to 256633 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All ATG20 GO evidence and references
  View Computational GO annotations for ATG20
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 4 genes
Classical genetics
Large-scale survey
63 total interaction(s) for 49 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 3
  • Affinity Capture-RNA: 1
  • Affinity Capture-Western: 5
  • Biochemical Activity: 2
  • PCA: 4
  • Reconstituted Complex: 2
  • Two-hybrid: 16

Genetic Interactions
  • Negative Genetic: 16
  • Phenotypic Enhancement: 6
  • Positive Genetic: 7
  • Synthetic Rescue: 1

Expression Summary
Length (a.a.) 640
Molecular Weight (Da) 72,546
Isoelectric Point (pI) 6.98
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrIV:258555 to 256633 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2004-02-11 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1923 258555..256633 2004-02-11 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000002271

about the Cytoplasm-to-vacuole targeting (Cvt) pathway

Cytoplasm-to-vacuole targeting (Cvt) is a constitutive and specific form of autophagy that uses autophagosomal-like vesicles for selective transport of hydrolases aminopeptidase I (Lap4p) and alpha-mannosidase (Ams1p) to the vacuole (5, 6). Unlike autophagy, which is primarily a catabolic process, Cvt is a biosynthetic process. Like autophagosomes, Cvt vesicles form at a structure known as the phagophore assembly site (PAS) (also called the pre-autophagosomal structure). The PAS structure generates an isolation membrane (IM), which expands and eventually fuses along the edges to complete vesicle formation. At the vacuole, the outer membrane of the Cvt vesicle fuses with the vacuolar membrane, the vesicle is degraded, and the cargos are released and processed into their mature forms by vacuolar peptidases (reviewed in 7). The Cvt pathway has not been observed outside of yeast, and enzymes specifically involved in this pathway are not well conserved in other organisms (8 and references therein).

about ATG20

ATG20 encodes a member of the sorting nexin family, which includes proteins that contain a Phox homology (PX) phosphoinositide-binding domain and play a role in membrane protein sorting (9, 2). The Atg20p PX domain binds phosphatidylinositol 3-phosphate and is required for the protein's localization to the PAS, where Atg20p plays a role in the Cvt pathway (9, 3). Atg20p also localizes to endosomes, where it functions in endosomal sorting (2).

Null mutations in atg20 cause accumulation of the precursor form of Lap4p (aminopeptidase I) in rich media, a hallmark Cvt pathway phenotype, but do not affect autophagy (3, 10). The role of Atg20p in the Cvt pathway involves interaction with Snx4p (a sorting nexin that also carries a PX domain); this complex appears to interact with the Atg1p-Atg13p complex via interaction with Atg17p and Atg11p (3, reviewed in 6 and 8). The Atg20p-Snx4p complex also mediates endosomal sorting of the SNARE Snc1p, which is retrieved from post-Golgi endosomes back to the Golgi; Snc1p is mislocalized to the vacuole in an atg20 (or snx4) null mutant (2). Atg20p homologs are found in other yeast species but have not been found in filamentous fungi or higher eukaryotes (8).

about autophagy nomenclature

The initial identification of factors involved in autophagy was carried out by several independent labs, which led to a proliferation of nomenclature for the genes and gene products involved. The differing gene name acronyms from these groups included APG, AUT, CVT, GSA, PAG, PAZ, and PDD (1 and references therein). A concerted effort was made in 2003 by the scientists working in the field to unify the nomenclature for these genes, and "AuTophaGy-related" genes are now denoted by the letters ATG (1). In addition to the ATG gene names that have been assigned to S. cerevisiae proteins and their orthologs, several ATG gene names, including ATG25, ATG28, and ATG30, have been used to designate proteins in other ascomycete yeast species for which there is no identifiable equivalent in S. cerevisiae (8, 11).

Last updated: 2008-04-23 Contact SGD

References cited on this page View Complete Literature Guide for ATG20
1) Klionsky DJ, et al.  (2003) A unified nomenclature for yeast autophagy-related genes. Dev Cell 5(4):539-45
2) Hettema EH, et al.  (2003) Retromer and the sorting nexins Snx4/41/42 mediate distinct retrieval pathways from yeast endosomes. EMBO J 22(3):548-57
3) Nice DC, et al.  (2002) Cooperative binding of the cytoplasm to vacuole targeting pathway proteins, Cvt13 and Cvt20, to phosphatidylinositol 3-phosphate at the pre-autophagosomal structure is required for selective autophagy. J Biol Chem 277(33):30198-207
4) Ubersax JA, et al.  (2003) Targets of the cyclin-dependent kinase Cdk1. Nature 425(6960):859-64
5) Harding TM, et al.  (1996) Genetic and phenotypic overlap between autophagy and the cytoplasm to vacuole protein targeting pathway. J Biol Chem 271(30):17621-4
6) Yorimitsu T and Klionsky DJ  (2005) Atg11 links cargo to the vesicle-forming machinery in the cytoplasm to vacuole targeting pathway. Mol Biol Cell 16(4):1593-605
7) Kim J and Klionsky DJ  (2000) Autophagy, cytoplasm-to-vacuole targeting pathway, and pexophagy in yeast and mammalian cells. Annu Rev Biochem 69:303-42
8) Meijer WH, et al.  (2007) ATG genes involved in non-selective autophagy are conserved from yeast to man, but the selective Cvt and pexophagy pathways also require organism-specific genes. Autophagy 3(2):106-16
9) Yu JW and Lemmon MA  (2001) All phox homology (PX) domains from Saccharomyces cerevisiae specifically recognize phosphatidylinositol 3-phosphate. J Biol Chem 276(47):44179-84
10) Cheong H, et al.  (2005) Atg17 regulates the magnitude of the autophagic response. Mol Biol Cell 16(7):3438-53
11) Farre JC, et al.  (2008) PpAtg30 tags peroxisomes for turnover by selective autophagy. Dev Cell 14(3):365-76