FKS3/YMR306W Summary Help

Standard Name FKS3
Systematic Name YMR306W
Feature Type ORF, Verified
Description Protein involved in spore wall assembly; has similarity to 1,3-beta-D-glucan synthase catalytic subunits Fks1p and Gsc2p; the authentic, non-tagged protein is detected in highly purified mitochondria in high-throughput studies (1, 2, 3 and see Summary Paragraph)
Chromosomal Location
ChrXIII:881159 to 886516 | ORF Map | GBrowse
Gene Ontology Annotations All FKS3 GO evidence and references
  View Computational GO annotations for FKS3
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Regulators 12 genes
Classical genetics
Large-scale survey
20 total interaction(s) for 18 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 4
  • Affinity Capture-RNA: 1
  • PCA: 3

Genetic Interactions
  • Dosage Rescue: 1
  • Negative Genetic: 4
  • Positive Genetic: 3
  • Synthetic Lethality: 4

Expression Summary
Length (a.a.) 1,785
Molecular Weight (Da) 207,481
Isoelectric Point (pI) 8.06
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXIII:881159 to 886516 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..5358 881159..886516 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 | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000004923

FKS3 encodes a presumed subunit of 1,3-beta-D-glucan synthase, similar to Fks1p and Gsc2p. 1,3-beta-D-glucan synthase (GS) is an enzymatic complex in the plasma membrane responsible for the synthesis of 1,3-beta-D-glucan, a polysaccharide that is the main structural component of the cell wall (reviewed in 4). The GS complex consists of a catalytic subunit and a regulatory subunit, both of which are essential for the complex activity (5). The regulatory subunit is a GTP-binding protein encoded by RHO1, which acts as an activator responsive to cell morphogenesis signals (6, 7, 8). FKS1 and GSC2 are believed to encode the catalytic subunit with the activity of UDP-glucose:1,3-beta-D-glucan 3-beta-glucose transferase, which catalyzes the transfer of a glucose moiety from UDP-glucose to the glucan chain (9). The two genes encode closely related integral membrane proteins that appear to act as alternate subunits with overlapping functions. FKS1 is primarily expressed during vegetative growth, whereas GSC2 is induced under starvation, during sporulation, and in response to mating pheromones (1). Null mutation of either gene is not lethal, although the fks1 null mutant shows a decrease of glucan and an increase of the chitin and mannoprotein levels in the cell wall (10) and the gsc2 null mutant shows defects in spore wall formation (3). The double null mutant fks1 gsc2 is not viable, indicating that the GS function is essential (1). The third gene, FKS3, has been identified based on sequence similarity to FKS1 and GSC2 and shown to be involved in spore wall assembly by mutant analysis, but its exact function remains unclear (3).

Last updated: 2007-06-22 Contact SGD

References cited on this page View Complete Literature Guide for FKS3
1) Mazur P, et al.  (1995) Differential expression and function of two homologous subunits of yeast 1,3-beta-D-glucan synthase. Mol Cell Biol 15(10):5671-81
2) Reinders J, et al.  (2006) Toward the complete yeast mitochondrial proteome: multidimensional separation techniques for mitochondrial proteomics. J Proteome Res 5(7):1543-54
3) Ishihara S, et al.  (2007) Homologous subunits of 1,3-beta-glucan synthase are important for spore wall assembly in Saccharomyces cerevisiae. Eukaryot Cell 6(2):143-56
4) Klis FM, et al.  (2002) Dynamics of cell wall structure in Saccharomyces cerevisiae. FEMS Microbiol Rev 26(3):239-56
5) Mol PC, et al.  (1994) A GTP-binding protein regulates the activity of (1-->3)-beta-glucan synthase, an enzyme directly involved in yeast cell wall morphogenesis. J Biol Chem 269(49):31267-74
6) Drgonova J, et al.  (1996) Rho1p, a yeast protein at the interface between cell polarization and morphogenesis. Science 272(5259):277-9
7) Qadota H, et al.  (1996) Identification of yeast Rho1p GTPase as a regulatory subunit of 1,3-beta-glucan synthase. Science 272(5259):279-81
8) Mazur P and Baginsky W  (1996) In vitro activity of 1,3-beta-D-glucan synthase requires the GTP-binding protein Rho1. J Biol Chem 271(24):14604-9
9) Douglas CM, et al.  (1994) The Saccharomyces cerevisiae FKS1 (ETG1) gene encodes an integral membrane protein which is a subunit of 1,3-beta-D-glucan synthase. Proc Natl Acad Sci U S A 91(26):12907-11
10) Lesage G, et al.  (2004) Analysis of beta-1,3-glucan assembly in Saccharomyces cerevisiae using a synthetic interaction network and altered sensitivity to caspofungin. Genetics 167(1):35-49