PPN1/YDR452W Summary Help

Standard Name PPN1 1
Systematic Name YDR452W
Alias PHM5 2
Feature Type ORF, Verified
Description Vacuolar endopolyphosphatase with a role in phosphate metabolism; functions as a homodimer; relocalizes from vacuole to cytoplasm upon DNA replication stress (1, 2, 3 and see Summary Paragraph)
Chromosomal Location
ChrIV:1362878 to 1364902 | ORF Map | GBrowse
Gene Ontology Annotations All PPN1 GO evidence and references
  View Computational GO annotations for PPN1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 16 genes
Classical genetics
Large-scale survey
19 total interaction(s) for 18 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 12
  • Affinity Capture-RNA: 3
  • Two-hybrid: 1

Genetic Interactions
  • Phenotypic Enhancement: 1
  • Synthetic Lethality: 2

Expression Summary
Length (a.a.) 674
Molecular Weight (Da) 78,344
Isoelectric Point (pI) 6.85
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrIV:1362878 to 1364902 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..2025 1362878..1364902 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 | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000002860

Endopolyphosphatases (Ppn1) from yeast and animal cells hydrolyze inorganic polyphosphate (poly P) chains of many hundreds of phosphate residues into shorter lengths (4, 1). The limit digest consists predominantly of chains of 60 (P60) and 3 (P3) Pi residues (4, 1). Ppn1p of Saccharomyces cerevisiae, a homodimer of 35-kDa subunits (about 352-aa) is of vacuolar origin and requires the protease activation of a 75-kDa (674-aa) precursor polypeptide (4, 1, 5). Null mutants in ppn1 accumulate long-chain poly P and are defective in growth in minimal media (1). A double mutant of PPN1 and PPX1 (the gene encoding a potent exopolyphosphatase) loses viability rapidly in stationary phase (1). Whether this loss is a result of the excess of long-chain poly P or to the lack of shorter chains (i.e., poly P60 and P3) is unknown (1). Overexpression of the processed form of Ppn1p should provide a unique and powerful reagent to analyze poly P when the chain termini are unavailable to the actions of polyPase and poly P kinase.

Last updated: 2002-01-14 Contact SGD

References cited on this page View Complete Literature Guide for PPN1
1) Sethuraman A, et al.  (2001) The endopolyphosphatase gene: essential in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 98(15):8542-7
2) Ogawa N, et al.  (2000) New components of a system for phosphate accumulation and polyphosphate metabolism in Saccharomyces cerevisiae revealed by genomic expression analysis. Mol Biol Cell 11(12):4309-21
3) 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
4) Kumble KD and Kornberg A  (1996) Endopolyphosphatases for long chain inorganic polyphosphate in yeast and mammals. J Biol Chem 271(43):27146-51
5) Reggiori F and Pelham HR  (2001) Sorting of proteins into multivesicular bodies: ubiquitin-dependent and -independent targeting. EMBO J 20(18):5176-86