ATG23/YLR431C Summary Help

Standard Name ATG23 1
Systematic Name YLR431C
Alias CVT23 2
Feature Type ORF, Verified
Description Peripheral membrane protein required for autophagy and CVT; required for cytoplasm-to-vacuole targeting (Cvt) pathway and efficient macroautophagy; cycles between the phagophore assembly site (PAS) and non-PAS locations; forms a complex with Atg9p and Atg27p (2, 3 and see Summary Paragraph)
Name Description AuTophaGy related 1
Chromosomal Location
ChrXII:1001703 to 1000342 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All ATG23 GO evidence and references
  View Computational GO annotations for ATG23
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 2 genes
Classical genetics
Large-scale survey
53 total interaction(s) for 37 unique genes/features.
Physical Interactions
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 4
  • Co-localization: 4
  • Two-hybrid: 6

Genetic Interactions
  • Negative Genetic: 15
  • Positive Genetic: 22

Expression Summary
Length (a.a.) 453
Molecular Weight (Da) 51,540
Isoelectric Point (pI) 6.01
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXII:1001703 to 1000342 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1362 1001703..1000342 2011-02-03 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 SGDIDS000004423

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 (4, 5). 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 6). The Cvt pathway has not been observed outside of yeast, and enzymes specifically involved in this pathway are not well conserved in other organisms (7 and references therein).

about ATG23

Atg23p function is essential for the Cvt pathway, but not for the related process of autophagy (8). An atg23 null mutant is defective for maturation of proaminopeptidase I (Lap4p), indicating a defect in Cvt pathway function, but can perform autophagy, albeit with reduced efficiency relative to wild-type cells (2, 8).

Atg23p is a peripheral membrane protein that localizes to the phagophore assembly site (PAS) as well as to non-PAS cytoplasmic sites, in both nutrient-rich and starvation conditions (2, 9). Atg23p cycles between these locations and does not remain associated with the completed Cvt vesicle; rather, it is retrieved for reuse (reviewed in 3). Anterograde movement of Atg23p to the PAS requires Atg27p and Atg9p, and retrograde movement from the PAS requires the Atg1p-Atg13p complex (2, 9, 3). Atg23p is also required for similar cycling of Atg9p and Atg27p between these locations; moreover, the three proteins form a complex in which Atg23p and Atg27p both interact directly with Atg9p but not with each other (3).

Atg23p is not widely conserved and appears to be found only in species closely related to S. cerevisiae (7, 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 (7, 10).

Last updated: 2008-04-23 Contact SGD

References cited on this page View Complete Literature Guide for ATG23
1) Klionsky DJ, et al.  (2003) A unified nomenclature for yeast autophagy-related genes. Dev Cell 5(4):539-45
2) Tucker KA, et al.  (2003) Atg23 is essential for the cytoplasm to vacuole targeting pathway and efficient autophagy but not pexophagy. J Biol Chem 278(48):48445-52
3) Legakis JE, et al.  (2007) A cycling protein complex required for selective autophagy. Autophagy 3(5):422-32
4) 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
5) 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
6) 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
7) 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
8) Meiling-Wesse K, et al.  (2004) ATG23, a novel gene required for maturation of proaminopeptidase I, but not for autophagy. FEMS Yeast Res 4(4-5):459-65
9) Reggiori F, et al.  (2004) The Atg1-Atg13 complex regulates Atg9 and Atg23 retrieval transport from the pre-autophagosomal structure. Dev Cell 6(1):79-90
10) Farre JC, et al.  (2008) PpAtg30 tags peroxisomes for turnover by selective autophagy. Dev Cell 14(3):365-76