STE4/YOR212W Summary Help

Standard Name STE4 1
Systematic Name YOR212W
Alias HMD2 2
Feature Type ORF, Verified
Description G protein beta subunit; forms a dimer with Ste18p to activate the mating signaling pathway, forms a heterotrimer with Gpa1p and Ste18p to dampen signaling; may recruit Rho1p to the polarized growth site during mating; contains WD40 repeats (3, 4 and see Summary Paragraph)
Name Description STErile 1
Chromosomal Location
ChrXV:742910 to 744181 | ORF Map | GBrowse
Genetic position: 124 cM
Gene Ontology Annotations All STE4 GO evidence and references
  View Computational GO annotations for STE4
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 2 genes
Classical genetics
Large-scale survey
163 total interaction(s) for 68 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 24
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 22
  • Biochemical Activity: 1
  • Co-purification: 1
  • PCA: 1
  • Reconstituted Complex: 8
  • Two-hybrid: 33

Genetic Interactions
  • Dosage Growth Defect: 5
  • Dosage Lethality: 1
  • Dosage Rescue: 17
  • Phenotypic Enhancement: 15
  • Phenotypic Suppression: 12
  • Synthetic Growth Defect: 1
  • Synthetic Lethality: 1
  • Synthetic Rescue: 19

Expression Summary
Length (a.a.) 423
Molecular Weight (Da) 46,581
Isoelectric Point (pI) 6.11
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXV:742910 to 744181 | ORF Map | GBrowse
Genetic position: 124 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1272 742910..744181 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 SGDIDS000005738

STE4 encodes the beta subunit of the heterotrimeric G protein involved in the mating pathway (3). Yeast respond to mating pheromone by transducing the pheromone signal through a well-studied mitogen-activated protein kinase (MAPK) cascade (reviewed in 5, 6). The first step in the mating pathway is the binding of mating pheromone to its receptor; the pheromone receptors are encoded by STE2 in MATa cells and STE3 in MATalpha cells (7, 8). These receptors transmit their signals through a heterotrimeric G protein consisting of Gpa1p, the G-alpha subunit, Ste4p, the beta subunit, and Ste18p, the gamma subunit (9, 6, 5). After binding pheromone, the pheromone receptor undergoes a conformational change and there is an exchange of GDP for GTP on Gpa1p. In its GTP-bound form, Gpa1p has less affinity for the Ste4p-Ste18p (beta-gamma) complex, and the latter is released and able to activate downstream components of the pheromone response pathway (9, 6, 5). The beta-gamma complex binds to both the scaffolding protein Ste5p, facilitating recruitment of Ste5p and its associated kinases (Ste11p, Ste7p, and Fus3p) to the plasma membrane, and to the PAK kinase Ste20p (10, 11, 12, 13). The Ste4p-Ste18p dimer also interacts with a complex of Far1p and Cdc24p; in total, these interactions induce expression of genes involved in mating, polarization of cell growth, and ultimately cell and nuclear fusion (reviewed in 14).

ste4 null mutants do not accumulate Ste18p to normal levels, and Ste4p is not localized to the plasma membrane in ste18 null mutants, indicating that beta-gamma dimer formation is required for function (15). Ste4p is rapidly phosphorylated upon addition of pheromone to cells; it appears that this modification does not affect Ste4p's function in pheromone signaling (16, 17).

Last updated: 2007-06-03 Contact SGD

References cited on this page View Complete Literature Guide for STE4
1) Hartwell LH  (1980) Mutants of Saccharomyces cerevisiae unresponsive to cell division control by polypeptide mating hormone. J Cell Biol 85(3):811-22
2) Sugimoto K, et al.  (1995) Dosage suppressors of the dominant G1 cyclin mutant CLN3-2: identification of a yeast gene encoding a putative RNA/ssDNA binding protein. Mol Gen Genet 248(6):712-8
3) Whiteway M, et al.  (1989) The STE4 and STE18 genes of yeast encode potential beta and gamma subunits of the mating factor receptor-coupled G protein. Cell 56(3):467-77
4) Bar EE, et al.  (2003) Gbetagamma recruits Rho1 to the site of polarized growth during mating in budding yeast. J Biol Chem 278(24):21798-804
5) Herskowitz I  (1995) MAP kinase pathways in yeast: for mating and more. Cell 80(2):187-97
6) Konopka JB and Fields S  (1992) The pheromone signal pathway in Saccharomyces cerevisiae. Antonie Van Leeuwenhoek 62(1-2):95-108
7) Burkholder AC and Hartwell LH  (1985) The yeast alpha-factor receptor: structural properties deduced from the sequence of the STE2 gene. Nucleic Acids Res 13(23):8463-75
8) Hagen DC, et al.  (1986) Evidence the yeast STE3 gene encodes a receptor for the peptide pheromone a factor: gene sequence and implications for the structure of the presumed receptor. Proc Natl Acad Sci U S A 83(5):1418-22
9) Blumer KJ and Thorner J  (1990) Beta and gamma subunits of a yeast guanine nucleotide-binding protein are not essential for membrane association of the alpha subunit but are required for receptor coupling. Proc Natl Acad Sci U S A 87(11):4363-7
10) Mahanty SK, et al.  (1999) Nuclear shuttling of yeast scaffold Ste5 is required for its recruitment to the plasma membrane and activation of the mating MAPK cascade. Cell 98(4):501-12
11) Pryciak PM and Huntress FA  (1998) Membrane recruitment of the kinase cascade scaffold protein Ste5 by the Gbetagamma complex underlies activation of the yeast pheromone response pathway. Genes Dev 12(17):2684-97
12) Dowell SJ, et al.  (1998) Mapping of a yeast G protein betagamma signaling interaction. Genetics 150(4):1407-17
13) Leeuw T, et al.  (1998) Interaction of a G-protein beta-subunit with a conserved sequence in Ste20/PAK family protein kinases. Nature 391(6663):191-5
14) Bardwell L  (2005) A walk-through of the yeast mating pheromone response pathway. Peptides 26(2):339-50
15) Hirschman JE, et al.  (1997) The G beta gamma complex of the yeast pheromone response pathway. Subcellular fractionation and protein-protein interactions. J Biol Chem 272(1):240-8
16) Cole GM and Reed SI  (1991) Pheromone-induced phosphorylation of a G protein beta subunit in S. cerevisiae is associated with an adaptive response to mating pheromone. Cell 64(4):703-16
17) Li E, et al.  (1998) Phosphorylation of the pheromone-responsive Gbeta protein of Saccharomyces cerevisiae does not affect its mating-specific signaling function. Mol Gen Genet 258(6):608-18