PHO2/YDL106C Summary Help

Standard Name PHO2
Systematic Name YDL106C
Alias BAS2 1 , GRF10
Feature Type ORF, Verified
Description Homeobox transcription factor; regulatory targets include genes involved in phosphate metabolism; binds cooperatively with Pho4p to the PHO5 promoter; phosphorylation of Pho2p facilitates interaction with Pho4p; relocalizes to the cytosol in response to hypoxia (2, 3, 4, 5 and see Summary Paragraph)
Also known as: phoB 6
Name Description PHOsphate metabolism
Chromosomal Location
ChrIV:271901 to 270222 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: -58.01 cM
Gene Ontology Annotations All PHO2 GO evidence and references
  View Computational GO annotations for PHO2
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Targets 142 genes
Regulators 7 genes
Classical genetics
reduction of function
Large-scale survey
110 total interaction(s) for 81 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 18
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 4
  • Biochemical Activity: 1
  • PCA: 1
  • Reconstituted Complex: 14
  • Two-hybrid: 11

Genetic Interactions
  • Dosage Rescue: 1
  • Negative Genetic: 38
  • Phenotypic Enhancement: 2
  • Phenotypic Suppression: 3
  • Positive Genetic: 9
  • Synthetic Growth Defect: 4
  • Synthetic Lethality: 1
  • Synthetic Rescue: 1

Expression Summary
Length (a.a.) 559
Molecular Weight (Da) 63,390
Isoelectric Point (pI) 4.76
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrIV:271901 to 270222 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: -58.01 cM
Last Update Coordinates: 2004-02-11 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1680 271901..270222 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 SGDIDS000002264

PHO2, also known as BAS2 or GRF10, encodes a homeodomain transcriptional activator that activates transcription in a combinatorial manner (3,2). Pho2p is required to express genes in several different pathways such as purine nucleotide biosynthesis, histidine biosynthesis, and phosphate utilization (7). Genes that are known to be regulated by Pho2p include PHO5, PHO81, HIS4, CYC1, TRP4, HO, ADE1, ADE2, ADE5,7 and ADE8 (4). Although purified Pho2p has been shown in vitro to have low affinity DNA binding activity, in vivo, it activates transcription along with one of at least three distinct partner proteins: the zinc finger protein Swi5p (8), the basic-helix-loop-helix factor Pho4p (9), and Bas1p, a myb-like activator (7). Pho2p and Pho4p cooperatively bind to the promoter site of PHO5 (which encodes for a secreted acid phosphatase) and are required for PHO5 expression when cells are starved of phosphate (10). Pho2p and Swi5p together activate HO, while Pho2p and Bas1p activate genes in the purine and histidine biosynthesis pathways (10). Pho2p is phosphorylated by cdc2/CDC28-type kinase at the 'SPIK' site (amino acids 230-233). This phosphorylation of Pho2p facilitates the interaction between Pho2p and Pho4p which is required for PHO5 expression under low phosphate conditions. Deletion and point mutation analyses have revealed that the homeodomain (amino acids 77-136) is necessary but not sufficient for cooperative DNA binding, and that a large C-terminal region (amino acids 112-404), including the Pho80p homologous region (amino acids 241-258), is required for interaction with its partners Swi5p, Pho4p, and Bas1p (4).

Last updated: 2003-03-13 Contact SGD

References cited on this page View Complete Literature Guide for PHO2
1) Arndt KT, et al.  (1987) Multiple global regulators control HIS4 transcription in yeast. Science 237(4817):874-80
2) Lenburg ME and O'Shea EK  (1996) Signaling phosphate starvation. Trends Biochem Sci 21(10):383-7
3) Berben G, et al.  (1988) Studies on the structure, expression and function of the yeast regulatory gene PHO2. Gene 66(2):307-12
4) Liu C, et al.  (2000) Regulation of the yeast transcriptional factor PHO2 activity by phosphorylation. J Biol Chem 275(41):31972-8
5) Ghosh Dastidar R, et al.  (2012) The nuclear localization of SWI/SNF proteins is subjected to oxygen regulation. Cell Biosci 2(1):30
6) To-E A, et al.  (1973) Isolation and characterization of acid phosphatase mutants in Saccharomyces cerevisiae. J Bacteriol 113(2):727-38
7) Daignan-Fornier B and Fink GR  (1992) Coregulation of purine and histidine biosynthesis by the transcriptional activators BAS1 and BAS2. Proc Natl Acad Sci U S A 89(15):6746-50
8) Brazas RM and Stillman DJ  (1993) The Swi5 zinc-finger and Grf10 homeodomain proteins bind DNA cooperatively at the yeast HO promoter. Proc Natl Acad Sci U S A 90(23):11237-41
9) Vogel K, et al.  (1989) The two positively acting regulatory proteins PHO2 and PHO4 physically interact with PHO5 upstream activation regions. Mol Cell Biol 9(5):2050-7
10) Bhoite LT, et al.  (2002) Mutations in the pho2 (bas2) transcription factor that differentially affect activation with its partner proteins bas1, pho4, and swi5. J Biol Chem 277(40):37612-8
11) Harbison CT, et al.  (2004) Transcriptional regulatory code of a eukaryotic genome. Nature 431(7004):99-104
12) Zhu C, et al.  (2009) High-resolution DNA-binding specificity analysis of yeast transcription factors. Genome Res 19(4):556-66
13) Badis G, et al.  (2008) A library of yeast transcription factor motifs reveals a widespread function for Rsc3 in targeting nucleosome exclusion at promoters. Mol Cell 32(6):878-87