SUMMARY PARAGRAPH for GAD1
About glutamate degradation
In S. cerevisiae, the main pathway for glutamate degradation is catalyzed by the glutamate dehydrogenase encoded by GDH2 (glutamate decarboxylase Gad1p and then converted into succinate by the enzymes encoded by UGA1 and UGA2 (1). 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 (1). UGA1 and UGA2 expression is also upregulated in the presence of GABA which is mediated by the transcriptional activators Uga3p and Uga35p/Dal81p (2), 3). These transcription factors bind to upstream activation sites in the promoters of GABA-regulated genes known as the UAS-GABA (4, 3). Regulation of Gad1p is suggested to be linked to calcium levels as the protein is able to bind calmodulin (1). 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 (1, 2).
Last updated: 2007-10-03