PHO5/YBR093C Summary Help

Standard Name PHO5
Systematic Name YBR093C
Feature Type ORF, Verified
Description Repressible acid phosphatase; 1 of 3 repressible acid phosphatases that also mediates extracellular nucleotide-derived phosphate hydrolysis; secretory pathway derived cell surface glycoprotein; induced by phosphate starvation and coordinately regulated by PHO4 and PHO2 (1, 2, 3 and see Summary Paragraph)
Also known as: phoE 4
Name Description PHOsphate metabolism
Chromosomal Location
ChrII:430951 to 429548 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: 47 cM
Gene Ontology Annotations All PHO5 GO evidence and references
  View Computational GO annotations for PHO5
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 17 genes
Classical genetics
reduction of function
Large-scale survey
40 total interaction(s) for 37 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 6
  • Co-purification: 1
  • Reconstituted Complex: 1

Genetic Interactions
  • Dosage Growth Defect: 3
  • Dosage Lethality: 2
  • Dosage Rescue: 1
  • Negative Genetic: 15
  • Positive Genetic: 4
  • Synthetic Growth Defect: 3
  • Synthetic Lethality: 4

Expression Summary
Length (a.a.) 467
Molecular Weight (Da) 52,858
Isoelectric Point (pI) 4.48
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrII:430951 to 429548 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: 47 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1997-01-28
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1404 430951..429548 2011-02-03 1997-01-28
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 SGDIDS000000297

PHO5 encodes the major phosphate-regulated secreted acid phosphatase in budding yeast (5, 1). It is highly expressed under low-phosphate conditions and repressed when phosphate is abundant. There are two similarly regulated phosphatases, Pho10p and Pho11p, that supply less than 10% of secreted acid phosphatase activity when cells are starved for phosphate (6). One other acid phosphatase, Pho3p, is regulated in the opposite manner, being induced under high-phosphate conditions (7). The acid phosphatases are secreted from the cell and are predominantly found in the periplasmic space (7). Phosphatases and phosphate transporters such as Pho84p help maintain the appropriate level of bioavailable phosphate in the cell.

PHO5 regulation has been extensively researched (5). Under high-phosphate conditions, PHO5 is inactive and its promoter is protected by four positioned nucleosomes (6, 7). When phosphate is depleted, Pho4p, a basic helix-loop-helix transcription factor, and Pho2p, a homeodomain protein, act cooperatively to bind the PHO5 promoter and activate PHO5 transcription (2, 1). Pho4p activity is regulated by the Pho80p(cyclin)/Pho85p(cyclin-dependent kinase) complex, which is in turn regulated by Pho81p, a cyclin-dependent kinase inhibitor (8, 9).

Last updated: 1999-09-01 Contact SGD

References cited on this page View Complete Literature Guide for PHO5
1) Lenburg ME and O'Shea EK  (1996) Signaling phosphate starvation. Trends Biochem Sci 21(10):383-7
2) Barbaric S, et al.  (1996) The homeodomain protein Pho2 and the basic-helix-loop-helix protein Pho4 bind DNA cooperatively at the yeast PHO5 promoter. Nucleic Acids Res 24(22):4479-86
3) Kennedy EJ, et al.  (2005) Pho5p and newly identified nucleotide pyrophosphatases/ phosphodiesterases regulate extracellular nucleotide phosphate metabolism in Saccharomyces cerevisiae. Eukaryot Cell 4(11):1892-901
4) To-E A, et al.  (1973) Isolation and characterization of acid phosphatase mutants in Saccharomyces cerevisiae. J Bacteriol 113(2):727-38
5) Oshima Y  (1997) The phosphatase system in Saccharomyces cerevisiae. Genes Genet Syst 72(6):323-34
6) Svaren J and Horz W  (1997) Transcription factors vs nucleosomes: regulation of the PHO5 promoter in yeast. Trends Biochem Sci 22(3):93-7
7) Vogel K and Hinnen A  (1990) The yeast phosphatase system. Mol Microbiol 4(12):2013-7
8) McAndrew PC, et al.  (1998) Requirements for chromatin modulation and transcription activation by the Pho4 acidic activation domain. Mol Cell Biol 18(10):5818-27
9) O'Neill EM, et al.  (1996) Regulation of PHO4 nuclear localization by the PHO80-PHO85 cyclin-CDK complex. Science 271(5246):209-12