APA1/YCL050C Summary Help

Standard Name APA1 1
Systematic Name YCL050C
Alias DTP1
Feature Type ORF, Verified
Description AP4A phosphorylase; bifunctional diadenosine 5',5'''-P1,P4-tetraphosphate phosphorylase and ADP sulfurylase involved in catabolism of bis(5'-nucleosidyl) tetraphosphates; catalyzes phosphorolysis of dinucleoside oligophosphates, cleaving substrates' alpha/beta-anhydride bond and introducing Pi into the beta-position of the corresponding NDP formed; protein abundance increases under DNA replication stress; APA1 has a paralog, APA2, that arose from the whole genome duplication (2, 3, 4, 5, 6 and see Summary Paragraph)
Name Description AP4A phosphorylase
Chromosomal Location
ChrIII:38801 to 37836 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: -33 cM
Gene Ontology Annotations All APA1 GO evidence and references
  View Computational GO annotations for APA1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Regulators 7 genes
Classical genetics
Large-scale survey
27 total interaction(s) for 22 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 13
  • Affinity Capture-RNA: 1
  • Biochemical Activity: 1
  • PCA: 2

Genetic Interactions
  • Negative Genetic: 7
  • Synthetic Growth Defect: 1
  • Synthetic Lethality: 2

Expression Summary
Length (a.a.) 321
Molecular Weight (Da) 36,492
Isoelectric Point (pI) 4.77
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrIII:38801 to 37836 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: -33 cM
Last Update Coordinates: 2000-09-13 | Sequence: 2000-09-13
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..966 38801..37836 2000-09-13 2000-09-13
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000000555

APA1 and APA2 encode diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) phosphorylases, which catabolize bis(5'-nucleosidyl) tetraphosphates (2, 1). The APA1 gene product also exhibits ADP sulfurylase activity (1). Ap4A phosphorylases catalyze phosphorolysis of dinucleoside oligophosphates, always cleaving the substrates' alpha,beta-anhydride bond and introducing Pi into the beta-position of the corresponding NDP formed (7, 5). The enzymatic reaction is dependent on the presence of divalent metal ions; Mn2+ or Mg2+ sustain the greatest rates of reaction (8). Mn2+, Mg2+, and Ca2+ sustain phosphorolysis by both Apa1p and Apa2p, whereas Co2+ and Cd2+ stimulate only Apa2p activity (2). Several bis(5'-nucleosidyl) tetraphosphates (Ap4A, Ap4C, Ap4G, Ap4U, Gp4G, Gp4U) are substrates of the two enzymes, but Apa2p shows a preference for A-containing substrates (2). The two enzymes catalyze adenosine 5'-phosphosulfate phosphorolysis or an exchange reaction between Pi and the beta-phosphate of any nucleoside diphosphate (2). They can also produce Ap4A at the expense of ATP and ADP (2).

APA1 and APA2 are paralogs that arose from the whole genome duplication, and share 60% amino acid sequence identity (2, 4). Disruption of either APA1 or APA2 shows that neither gene is essential for viability (9, 2, 1). The apa1 apa2 double mutant exhibits increased concentrations of all bis(5'-nucleosidyl) tetraphosphates (2). Overexpression of APA1 decreases the intracellular glutathione content (10).

Last updated: 2012-08-17 Contact SGD

References cited on this page View Complete Literature Guide for APA1
1) Plateau P, et al.  (1989) Isolation, characterization, and inactivation of the APA1 gene encoding yeast diadenosine 5',5'''-P1,P4-tetraphosphate phosphorylase. J Bacteriol 171(12):6437-45
2) Plateau P, et al.  (1990) Catabolism of bis(5'-nucleosidyl) tetraphosphates in Saccharomyces cerevisiae. J Bacteriol 172(12):6892-9
3) Booth JW and Guidotti G  (1995) An alleged yeast polyphosphate kinase is actually diadenosine-5', 5"'-P1,P4-tetraphosphate alpha,beta-phosphorylase. J Biol Chem 270(33):19377-82
4) Byrne KP and Wolfe KH  (2005) The Yeast Gene Order Browser: combining curated homology and syntenic context reveals gene fate in polyploid species. Genome Res 15(10):1456-61
5) Lazewska D and Guranowski A  (1990) P alpha-chiral phosphorothioate analogues of bis(5'-adenosyl)tetraphosphate (Ap4A); their enzymatic synthesis and degradation. Nucleic Acids Res 18(20):6083-8
6) Tkach JM, et al.  (2012) Dissecting DNA damage response pathways by analysing protein localization and abundance changes during DNA replication stress. Nat Cell Biol 14(9):966-76
7) Guranowski A and Blanquet S  (1986) Diadenosine 5',5'''-P1, P4-tetraphosphate alpha, beta-phosphorylase from yeast supports nucleoside diphosphate-phosphate exchange. J Biol Chem 261(13):5943-6
8) Guranowski A and Blanquet S  (1985) Phosphorolytic cleavage of diadenosine 5',5'''-P1,P4-tetraphosphate. Properties of homogeneous diadenosine 5',5'''-P1,P4-tetraphosphate alpha, beta-phosphorylase from Saccharomyces cerevisiae. J Biol Chem 260(6):3542-7
9) Avila DM, et al.  (1991) A paradoxical increase of a metabolite upon increased expression of its catabolic enzyme: the case of diadenosine tetraphosphate (Ap4A) and Ap4A phosphorylase I in Saccharomyces cerevisiae. J Bacteriol 173(24):7875-80
10) Hara KY, et al.  (2012) Improvement of glutathione production by metabolic engineering the sulfate assimilation pathway of Saccharomyces cerevisiae. Appl Microbiol Biotechnol 94(5):1313-9