UGA1/YGR019W Summary Help

Standard Name UGA1 1
Systematic Name YGR019W
Feature Type ORF, Verified
Description Gamma-aminobutyrate (GABA) transaminase; also known as 4-aminobutyrate aminotransferase; involved in the 4-aminobutyrate and glutamate degradation pathways; required for normal oxidative stress tolerance and nitrogen utilization; protein abundance increases in response to DNA replication stress (1, 2, 3, 4 and see Summary Paragraph)
Name Description Utilization of GAba 1
Chromosomal Location
ChrVII:525229 to 526644 | ORF Map | GBrowse
Gene Ontology Annotations All UGA1 GO evidence and references
  View Computational GO annotations for UGA1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 8 genes
Classical genetics
Large-scale survey
41 total interaction(s) for 35 unique genes/features.
Physical Interactions
  • Affinity Capture-RNA: 2
  • Two-hybrid: 1

Genetic Interactions
  • Negative Genetic: 23
  • Phenotypic Enhancement: 3
  • Positive Genetic: 3
  • Synthetic Growth Defect: 5
  • Synthetic Lethality: 4

Expression Summary
Length (a.a.) 471
Molecular Weight (Da) 52,946
Isoelectric Point (pI) 6.78
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrVII:525229 to 526644 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1416 525229..526644 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 SGDIDS000003251

In S. cerevisiae the non-protein amino acid gamma-aminobutyric acid (GABA) plays a role in nitrogen utilization and oxidative stress tolerance (2, 1). GABA accumulation occurs through permease-mediated uptake by Uga4p, Put4p, and Gap1p, or intracellular production via glutamate degradation by the glutamate decarboxylase Gad1p (5 and references therein). GABA degradation into succinate is a two-step process mediated by the gene products of UGA1 and UGA2. UGA1 encodes a 4-aminobutyrate aminotransferase that deaminates GABA to succinate semialdehyde which in turn is converted to succinate by the succinate semialdehyde dehydrogenase (SSADH) encoded by UGA2 (1). S. cerevisiae cells in which GABA degradation is blocked are more sensitive to oxidative stress and can no longer grow on GABA as their sole nitrogen source (2, 1).

The presence of GABA causes an increase in expression of UGA1 and UGA2 which is mediated by the transcriptional activators Uga3p, Dal81p, and Gln3p (1, 6, 7, 2). Uga3p and Dal81p bind to upstream activation sites called the UAS-GABA element found in the promoters of GABA regulated genes. (8, 6). Gln3p is involved in a more general nitrogen regulation of transcription through binding of the promoter element UAS-GATA (2 and references therein). Levels of UGA2 transcript are also upregulated under conditions of oxidative stress (2).

GABA-transaminases have been identified in various organisms, including UGA1 homologs from yeasts Ustilago maydis and Aspergillus nidulans (9). Mutations in the human GABA-aminotransferase gene, ABAT, have been associated with the disease GABA-transaminase deficiency (OMIM), the clinical features of which include developmental and neurological abnormalities.

About glutamate degradation

In S. cerevisiae, the main pathway for glutamate degradation is catalyzed by the glutamate dehydrogenase encoded by GDH2 (10). However, glutamate can also by degraded into gamma-aminobutyrate (GABA) by the glutamate decarboxylase Gad1p and then converted into succinate by the enzymes encoded by UGA1 and UGA2 (2). Glutamate degradation by this pathway and expression of its genes have been shown to be important for oxidative stress tolerance. Conditions of oxidative stress elevate the transcript levels of GAD1 and UGA2 (2). UGA1 and UGA2 expression is also upregulated in the presence of GABA which is mediated by the transcriptional activators Uga3p and Uga35p/Dal81p (1), 6). These transcription factors bind to upstream activation sites in the promoters of GABA-regulated genes known as the UAS-GABA (8, 6). Regulation of Gad1p is suggested to be linked to calcium levels as the protein is able to bind calmodulin (2). S. cerevisiae cells in which this pathway is blocked are more sensitive to oxidative stress and can no longer grow on GABA as their sole nitrogen source (2, 1).

Last updated: 2007-05-25 Contact SGD

References cited on this page View Complete Literature Guide for UGA1
1) Ramos F, et al.  (1985) Mutations affecting the enzymes involved in the utilization of 4-aminobutyric acid as nitrogen source by the yeast Saccharomyces cerevisiae. Eur J Biochem 149(2):401-4
2) Coleman ST, et al.  (2001) Expression of a glutamate decarboxylase homologue is required for normal oxidative stress tolerance in Saccharomyces cerevisiae. J Biol Chem 276(1):244-50
3) Tadi D, et al.  (1999) Selection of genes repressed by cAMP that are induced by nutritional limitation in Saccharomyces cerevisiae. Yeast 15(16):1733-45
4) 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
5) Andre B, et al.  (1993) Cloning and expression of the UGA4 gene coding for the inducible GABA-specific transport protein of Saccharomyces cerevisiae. Mol Gen Genet 237(1-2):17-25
6) Vissers S, et al.  (1989) Positive and negative regulatory elements control the expression of the UGA4 gene coding for the inducible 4-aminobutyric-acid-specific permease in Saccharomyces cerevisiae. Eur J Biochem 181(2):357-61
7) Talibi D, et al.  (1995) Cis- and trans-acting elements determining induction of the genes of the gamma-aminobutyrate (GABA) utilization pathway in Saccharomyces cerevisiae. Nucleic Acids Res 23(4):550-7
8) Idicula AM, et al.  (2002) Binding and activation by the zinc cluster transcription factors of Saccharomyces cerevisiae. Redefining the UASGABA and its interaction with Uga3p. J Biol Chem 277(48):45977-83
9) Straffon MJ, et al.  (1996) Characterization of the ugatA gene of Ustilago maydis, isolated by homology to the gatA gene of Aspergillus nidulans. Curr Genet 29(4):360-9
10) Miller SM and Magasanik B  (1990) Role of NAD-linked glutamate dehydrogenase in nitrogen metabolism in Saccharomyces cerevisiae. J Bacteriol 172(9):4927-35