High impact information on ECM38

• During growth on a preferred nitrogen source like NH(4)(+), CIS2 expression is repressed through a mechanism involving (at least) the Gln3-binding protein Ure2/GdhCR [1].
• We further show that Gzf3, another GATA zinc-finger protein, acts as a negative regulator in nitrogen-source control of CIS2 expression [1].
• The promoter region of CIS2 contains one stress-response element (CCCCT) and eight GAT(T/A)A core sequences, probably involved in nitrogen-regulated transcription [1].
• The V(max) (app)-increasing effect of gamma-GT concerns only the YCF1 system. gamma-GT in the vacuolar membrane activates the Ycf1p transporter, either directly or indirectly [2].
• Excretion of glutamate from radiolabelled GSH in isolated vacuoles containing gamma-GT was also measured [2].

Biological context of ECM38

• Cloning and sequencing the genes from these yeasts indicated the presence of 11 single nucleotide polymorphisms in the coding region and eight single nucleotide polymorphisms in the promoter region of the ECM38 gene of YPH499 (but none in that of BY4742) [3].
• It is proposed that gamma-GT and a L-Cys-Gly dipeptidase catalyse the complete hydrolysis of GSH stored in the central vacuole of the yeast cell, prior to release of its constitutive amino acids L-glutamate, L-cysteine and glycine into the cytoplasm [2].

Anatomical context of ECM38

• Vacuoles containing gamma-GT displayed practically the same K(m), but a higher V(max) (app) (150+/-12 nmol of GSH/min per mg of protein) [2].
• CT120 can interact with SLC3A2 (member 2 of solute carrier family 3) and GGTL3B (isoform of gamma-glutamyltranspeptidase-like 3) in eukaryotic cells by yeast two-hybrid screen and co-immunoprecipitation assay, which suggested that CT120 may assume very essential physiological functions involved in amino acid transport and glutathione metabolism [4].

Associations of ECM38 with chemical compounds

• The ECM38 gene encodes the gamma-glutamyl transpeptidase enzyme, an enzyme involved in glutathione turnover [3].
• In the yeast Saccharomyces cerevisiae, the enzyme gamma-glutamyl transpeptidase (gamma-GT; EC 2.3.2.2) is a glycoprotein that is bound to the vacuolar membrane [2].
• The gamma-glutamyltranspeptidase appears to be repressed by NH+4 and escapes to the regulatory circuits under the control of glutamine and the glutamate-dehydrogenase . NH+4 complex [5].

Other interactions of ECM38

• Induction of CIS2 expression during nitrogen starvation is dependent on Gln3 and Nil1 [1].
• The effectors governing the biosynthesis of cysteine synthase and gamma-cystathionase seemed different from those playing a role in gamma-GT regulation and it was only under conditions of total sulphate deprivation that all these enzymes were derepressed [6].
• The thiol-alkylators at 20 microM failed to inhibit four key enzymes (gamma-glutamyltranspeptidase, glutathione reductase, glutathione S-transferase and glutathione peroxidase) involved in glutathione utilization indicating that the inhibition of yeast-to-mycelium conversion is not mediated by the inhibition of glutathione metabolic enzymes [7].

References