PHO80/YOL001W Summary Help

Standard Name PHO80
Systematic Name YOL001W
Alias AGS3 1 , TUP7 2 , VAC5 3
Feature Type ORF, Verified
Description Cyclin; interacts with cyclin-dependent kinase Pho85p; regulates the response to nutrient levels and environmental conditions, including the response to phosphate limitation and stress-dependent calcium signaling (4, 5, 6 and see Summary Paragraph)
Also known as: phoR 7
Name Description PHOsphate metabolism
Chromosomal Location
ChrXV:325249 to 326130 | ORF Map | GBrowse
Genetic position: -1 cM
Gene Ontology Annotations All PHO80 GO evidence and references
  View Computational GO annotations for PHO80
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 1 genes
Classical genetics
reduction of function
Large-scale survey
480 total interaction(s) for 288 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 13
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 6
  • Biochemical Activity: 10
  • Co-crystal Structure: 1
  • Reconstituted Complex: 9
  • Two-hybrid: 7

Genetic Interactions
  • Dosage Growth Defect: 3
  • Dosage Rescue: 7
  • Negative Genetic: 188
  • Phenotypic Enhancement: 7
  • Phenotypic Suppression: 124
  • Positive Genetic: 70
  • Synthetic Growth Defect: 18
  • Synthetic Lethality: 6
  • Synthetic Rescue: 9

Expression Summary
Length (a.a.) 293
Molecular Weight (Da) 33,226
Isoelectric Point (pI) 9.66
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXV:325249 to 326130 | ORF Map | GBrowse
Genetic position: -1 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..882 325249..326130 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 | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000005361

Pho80p is one of 10 cyclins that interact with the cyclin-dependent kinase Pho85p (6, 8). Pho80p, Pcl6p, Pcl7p, Pcl8p, and Pcl10p belong to the Pho80p subfamily of cyclins, which primarily regulate the response to nutrient levels and environmental conditions (9). Pho80p provides the substrate specificity for the Pho85p kinase (10, 11). Under non-stress conditions, Pho80p-Pho85p phosphorylates key regulators of genes that are necessary for survival under stress. Phosphorylation prevents the translocation of these regulators (transcription factors and kinases) to the nucleus, thus repressing their activity (reviewed in 6).

Pho80p-Pho85p plays a central role in regulating the response to phosphate limitation. Under high phosphate conditions, Pho80p-Pho85p phosphorylates the transcription factor Pho4p, preventing its localization to the nucleus (12, 4). Under low phosphate conditions, Pho80-Pho85p is inactivated by the CDK inhibitor (CKI) Pho81p as well as by the small molecule inositol heptakisphosphate (IP7) (13, 14, 15). Inactivation of Pho80p-Pho85p allows an unphosphorylated Pho4p to translocate to the nucleus and activate the transcription of genes involved in phosphate uptake and storage (12, 4). Because Pho80p-Pho85p regulates Pho4p, which in turn regulates genes required for phosphate storage in the vacuole, pho80 mutants have vacuolar morphology and inheritance defects (16, 17, 3).

In addition to Pho4p, other substrates of Pho80p-Pho85p are involved in regulating the response to nutrient levels and environmental conditions. Pho80p-Pho85p phosphorylates Rim15p, a key protein kinase controlling the entry into stationary phase, suggesting that phosphate levels influence the decision to enter G0 (18). In the absence of stress conditions that activate calcium signalling, Crz1p is phosphorylated by Pho80p-Pho85p, preventing its nuclear localization and activation of genes necessary for the stress response (5). In addition, Pho81p and Pho80p-Pho85p appear to effect the expression of stress response genes controlled by post-diauxic shift independent of their role in regulating Pho4p localization (19).

Pho80p is phosphorylated by Pho85p; this phosphorylation is necessary for its function (20). Pho80p is a stable protein, with a half-life of more than 30 minutes (21).

Last updated: 2009-06-24 Contact SGD

References cited on this page View Complete Literature Guide for PHO80
1) Wickert S, et al.  (1998) A small protein (Ags1p) and the Pho80p-Pho85p kinase complex contribute to aminoglycoside antibiotic resistance of the yeast Saccharomyces cerevisiae. J Bacteriol 180(7):1887-94
2) Bisson LF and Thorner J  (1982) Mutations in the pho80 gene confer permeability to 5'-mononucleotides in Saccharomyces cerevisiae. Genetics 102(3):341-59
3) Nicolson TA, et al.  (1995) A truncated form of the Pho80 cyclin redirects the Pho85 kinase to disrupt vacuole inheritance in S. cerevisiae. J Cell Biol 130(4):835-45
4) O'Neill EM, et al.  (1996) Regulation of PHO4 nuclear localization by the PHO80-PHO85 cyclin-CDK complex. Science 271(5246):209-12
5) Sopko R, et al.  (2006) Mapping pathways and phenotypes by systematic gene overexpression. Mol Cell 21(3):319-30
6) Huang D, et al.  (2007) Pho85, a multifunctional cyclin-dependent protein kinase in budding yeast. Mol Microbiol 66(2):303-14
7) To-E A, et al.  (1973) Isolation and characterization of acid phosphatase mutants in Saccharomyces cerevisiae. J Bacteriol 113(2):727-38
8) Carroll AS and O'Shea EK  (2002) Pho85 and signaling environmental conditions. Trends Biochem Sci 27(2):87-93
9) Measday V, et al.  (1997) A family of cyclin-like proteins that interact with the Pho85 cyclin-dependent kinase. Mol Cell Biol 17(3):1212-23
10) Huang D, et al.  (1998) Cyclin partners determine Pho85 protein kinase substrate specificity in vitro and in vivo: control of glycogen biosynthesis by Pcl8 and Pcl10. Mol Cell Biol 18(6):3289-99
11) Huang K, et al.  (2007) Structure of the Pho85-Pho80 CDK-cyclin complex of the phosphate-responsive signal transduction pathway. Mol Cell 28(4):614-23
12) Kaffman A, et al.  (1994) Phosphorylation of the transcription factor PHO4 by a cyclin-CDK complex, PHO80-PHO85. Science 263(5150):1153-6
13) Schneider KR, et al.  (1994) Phosphate-regulated inactivation of the kinase PHO80-PHO85 by the CDK inhibitor PHO81. Science 266(5182):122-6
14) Lee YS, et al.  (2007) Regulation of a cyclin-CDK-CDK inhibitor complex by inositol pyrophosphates. Science 316(5821):109-12
15) Lee YS, et al.  (2008) Molecular basis of cyclin-CDK-CKI regulation by reversible binding of an inositol pyrophosphate. Nat Chem Biol 4(1):25-32
16) 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
17) Huang D, et al.  (2002) Dissection of a complex phenotype by functional genomics reveals roles for the yeast cyclin-dependent protein kinase Pho85 in stress adaptation and cell integrity. Mol Cell Biol 22(14):5076-88
18) Wanke V, et al.  (2005) Regulation of G0 entry by the Pho80-Pho85 cyclin-CDK complex. EMBO J 24(24):4271-8
19) Swinnen E, et al.  (2005) The minimum domain of Pho81 is not sufficient to control the Pho85-Rim15 effector branch involved in phosphate starvation-induced stress responses. Curr Genet 48(1):18-33
20) Waters NC, et al.  (2004) The yeast Pho80-Pho85 cyclin-CDK complex has multiple substrates. Curr Genet 46(1):1-9
21) Aviram S, et al.  (2008) Autophosphorylation-induced degradation of the Pho85 cyclin Pcl5 is essential for response to amino acid limitation. Mol Cell Biol 28(22):6858-69