PFY1/YOR122C Summary Help

Standard Name PFY1 1
Systematic Name YOR122C
Alias PRF1 , CLS5 2
Feature Type ORF, Verified
Description Profilin; binds actin, phosphatidylinositol 4,5-bisphosphate, and polyproline regions; involved in cytoskeleton organization; required for normal timing of actin polymerization in response to thermal stress; protein abundance increases in response to DNA replication stress; highly conserved protein; human PFN1 (profilin 1) complements temperature sensitive pfy1 mutants, PFN1 mutations are a rare cause of ALS (3, 4, 5, 6, 7 and see Summary Paragraph)
Name Description ProFilin of Yeast
Chromosomal Location
ChrXV:552887 to 552298 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: 64 cM
Gene Ontology Annotations All PFY1 GO evidence and references
  View Computational GO annotations for PFY1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 4 genes
Classical genetics
reduction of function
Large-scale survey
reduction of function
219 total interaction(s) for 178 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 2
  • Affinity Capture-RNA: 7
  • Affinity Capture-Western: 2
  • Biochemical Activity: 2
  • Co-crystal Structure: 1
  • Co-fractionation: 1
  • PCA: 2
  • Reconstituted Complex: 1
  • Two-hybrid: 10

Genetic Interactions
  • Dosage Growth Defect: 2
  • Dosage Lethality: 1
  • Dosage Rescue: 15
  • Negative Genetic: 15
  • Phenotypic Enhancement: 5
  • Phenotypic Suppression: 1
  • Positive Genetic: 2
  • Synthetic Growth Defect: 129
  • Synthetic Haploinsufficiency: 1
  • Synthetic Lethality: 17
  • Synthetic Rescue: 3

Expression Summary
Length (a.a.) 126
Molecular Weight (Da) 13,677
Isoelectric Point (pI) 5.63
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXV:552887 to 552298 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: 64 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..13 552887..552875 2011-02-03 1996-07-31
Intron 14..222 552874..552666 2011-02-03 1996-07-31
CDS 223..590 552665..552298 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 SGDIDS000005648

Profilin plays an important role in actin organization in all eukaryotic cells (8). Yeast profilin is an actin- and phosphatidylinositol 4,5-bisphosphate-binding protein that plays a role in the organization of the cytoskeleton (3), and resembles profilins from other organisms in molecular mass and function (9). Profilin mediates actin nucleation by an Arp2p/Arp3p-independent mechanism (10), and can sequester actin monomers, thereby reducing polymerization ability (11). Profilin also promotes rapid actin dynamics by regenerating ATP actin from ADP actin-cofilin generated during filament disassembly (12). Profilin may link signaling pathways to actin cytoskeleton organization by binding to phosphatidylinositol 4,5-bisphosphate and to polyproline stretches on several proteins (12).

Profilin plays a role in maintaining normal actin filament levels in response to shifts to high temperature. Cells lacking profilin display a greater drop in actin filament levels upon such temperature shifts, and are slower to recover to initial actin filament levels than are wild-type cells. Profilin null cells contain normal concentrations of actin filament while growing exponentially at room temperature, indicating that profilin is not essential for maintaining actin filament concentrations during steady-state growth (4).

Yeast cells can survive without detectable profilin, but such cells grow slowly, are temperature sensitive, lose the normal ellipsoidal shape of yeast cells, often become multinucleate, and generally grow much larger than wild-type cells. In addition, these cells exhibit delocalized deposition of cell wall chitin, have dramatically altered actin distributions, and exhibit abnormal bud formation, cytokinesis, and spore germination (9, 13, 14). Overexpression of profilin leads to no very obvious phenotype, but can compensate for the deleterious effects of too much actin in a profilin concentration-dependent manner (15). Mutations in the late secretory gene SEC3, and also in several other late secretory genes, are synthetically lethal with profilin mutations, suggesting a role for profilin in intracellular transport (14), and also cause defects in diploid-specific bud-site selection, indicating that the secretory pathway is especially crucial for maintaining budding polarity (16).

Profilin can be found in both the plasma membrane and cytosol. Actin is bound to the profilin localized in the cytosol. The association of profilin with the membrane is peripheral and mediated through interactions with phosphatidylinositol 4,5-bisphosphate. Depletion of plasma membrane phosphatidylinositol 4,5-bisphosphate levels results in translocation of profilin to the cytosol, suggesting that phosphoinositide metabolism plays a role in profilin localization (3).

Last updated: 2004-10-14 Contact SGD

References cited on this page View Complete Literature Guide for PFY1
1) Adams, A., et al.  (1989) Personal Communication, Mortimer Map Edition 10
2) Yoshida M, et al.  (2013) Profilin is required for Ca(2+) homeostasis and Ca (2+)-modulated bud formation in yeast. Mol Genet Genomics 288(7-8):317-28
3) Ostrander DB, et al.  (1995) Regulation of profilin localization in Saccharomyces cerevisiae by phosphoinositide metabolism. J Biol Chem 270(45):27045-50
4) Yeh J and Haarer BK  (1996) Profilin is required for the normal timing of actin polymerization in response to thermal stress. FEBS Lett 398(2-3):303-7
5) Eads JC, et al.  (1998) Structure determination and characterization of Saccharomyces cerevisiae profilin. Biochemistry 37(32):11171-81
6) 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
7) Figley MD, et al.  (2014) Profilin 1 Associates with Stress Granules and ALS-Linked Mutations Alter Stress Granule Dynamics. J Neurosci 34(24):8083-97
8) Marcoux N, et al.  (2000) Suppression of the profilin-deficient phenotype by the RHO2 signaling pathway in Saccharomyces cerevisiae. Genetics 156(2):579-92
9) Haarer BK, et al.  (1990) Purification of profilin from Saccharomyces cerevisiae and analysis of profilin-deficient cells. J Cell Biol 110(1):105-14
10) Sagot I, et al.  (2002) An actin nucleation mechanism mediated by Bni1 and profilin. Nat Cell Biol 4(8):626-31
11) Nefsky B and Bretscher A  (1992) Yeast actin is relatively well behaved. Eur J Biochem 206(3):949-55
12) Wolven AK, et al.  (2000) In vivo importance of actin nucleotide exchange catalyzed by profilin. J Cell Biol 150(4):895-904
13) Magdolen V, et al.  (1988) The intron-containing gene for yeast profilin (PFY) encodes a vital function. Mol Cell Biol 8(12):5108-15
14) Marcoux N, et al.  (1998) Overexpression of MID2 suppresses the profilin-deficient phenotype of yeast cells. Mol Microbiol 29(2):515-26
15) Magdolen V, et al.  (1993) High levels of profilin suppress the lethality caused by overproduction of actin in yeast cells. FEBS Lett 316(1):41-7
16) Haarer BK, et al.  (1996) SEC3 mutations are synthetically lethal with profilin mutations and cause defects in diploid-specific bud-site selection. Genetics 144(2):495-510