PHO4 BASIC INFORMATION
| Standard Name | PHO4 |
|---|---|
| Systematic Name | YFR034C |
| Feature Type | ORF, Verified |
| Description | Basic helix-loop-helix (bHLH) transcription factor of the myc-family; binds cooperatively with Pho2p to the PHO5 promoter; function is regulated by phosphorylation at multiple sites and by phosphate availability (1, 2, 3 and see Summary Paragraph) Also known as: phoD 4
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| Name Description | PHOsphate metabolism |
| GO Annotations | All PHO4 GO evidence and references |
|---|---|
| View Computational GO annotations for PHO4 | |
| Molecular Function | |
| Manually curated | |
| High-throughput | |
| Biological Process | |
| Manually curated | |
| Cellular Component | |
| Manually curated |
| Regulatory Role | |
|---|---|
| Binding motifs | PHO4 Transcription Factor Binding Sites and References |
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| Mutant Phenotype | All PHO4 Phenotype details and references |
|---|---|
| Classical genetics | |
| null |
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| overexpression |
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| reduction of function | |
| Large-scale survey | |
| null |
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| overexpression |
| Interactions | PHO4 All interactions details and references |
|---|---|
| 215 total interaction(s) for 159 unique genes/features. | |
| Physical Interactions |
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| Genetic Interactions |
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| External Links | All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | UniProtKB |
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| Primary SGDID | S000001930 |
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ADDITIONAL INFORMATION for PHO4
SUMMARY PARAGRAPH for PHO4
PHO4 was the first S. cerevisiae gene shown to encode a basic helix-loop-helix (bHLH) protein transcription factor (2). Pho4p binds to DNA sequences containing the core bHLH binding site, 5'-CACGTG-3'as a homodimer (5). This sequence is found in the promoters of a variety of genes positively regulated in response to phosphate availability like the PHO5 gene (3). Multiple phosphorylation sites on Pho4p play distinct roles in regulating its subcellular localization and its DNA binding function (1). The Pho80p-Pho85p kinase complex phosphorylates Pho4p on five Ser-Pro (SP) dipeptides referred to as SP1, SP2, SP3, SP4 and SP6 (1). Sites SP2 and SP3 regulate the nuclear export of Pho4p, site SP4 regulates the import of Pho4p and site SP6 regulates its interaction with Pho2p, which is required for expression of the acid phosphatase PHO5. The exact role of SP1 is still unknown (1). When phosphate is abundant, Pho4p is phosphorylated by the Pho80p-Pho85p complex and exported to the cytoplasm by the receptor Msn5p (6) where it is unable to activate transcription of phosphate-responsive genes such PHO5 (1). When phosphate is limiting, the cyclin-dependent kinase (CDK) inhibitor Pho81p inactivates the Pho80p-Pho85p complex, leading to accumulation of unphosphorylated Pho4p in the nucleus and subsequent activation of phosphate-responsive genes (7).
REFERENCES CITED ON THIS PAGE [View Complete Literature Guide for PHO4]
| 1) | Komeili A and O'Shea EK (1999) Roles of phosphorylation sites in regulating activity of the transcription factor Pho4. Science 284(5416):977-80 |
| 2) | Berben G, et al. (1990) The yeast regulatory gene PHO4 encodes a helix-loop-helix motif. Yeast 6(5):451-4 |
| 3) | Ogawa N and Oshima Y (1990) Functional domains of a positive regulatory protein, PHO4, for transcriptional control of the phosphatase regulon in Saccharomyces cerevisiae. Mol Cell Biol 10(5):2224-36 |
| 4) | To-E A, et al. (1973) Isolation and characterization of acid phosphatase mutants in Saccharomyces cerevisiae. J Bacteriol 113(2):727-38 |
| 5) | Shao D, et al. (1998) A cysteine residue in helixII of the bHLH domain is essential for homodimerization of the yeast transcription factor Pho4p. Nucleic Acids Res 26(3):710-4 |
| 6) | Kaffman A, et al. (1998) The receptor Msn5 exports the phosphorylated transcription factor Pho4 out of the nucleus. Nature 396(6710):482-6 |
| 7) | Kaffman A, et al. (1994) Phosphorylation of the transcription factor PHO4 by a cyclin-CDK complex, PHO80-PHO85. Science 263(5150):1153-6 |





