Human GAD2 blocking peptide

Pichia pastoris is greatly used as a protein expression system based on tightly regulated aldehyde oxidase 1 (AOX1) promoter (P-AOX1) that is induced by methanol; however, the use of methanol of highly expensive and dangerous. By deleting transcription repressors and overexpressing transcription activator of the P-AOX1, a methanol-independent strain MF1 (Delta mig1 Delta mig2 Delta nrg1-Mit1) has been previously constructed. This study investigated the transcriptomic and metabolomic profiles of the MF1 strain in response to different carbon sources, including methanol, glucose, and glycerol, in comparison with the wild-type strain. AOX expression was observed in all groups except the wild-type strains cultured in glucose and glycerol. Genes involved in methanol utilization and peroxisome biosynthesis were mainly upregulated in the mutant strain grown on glucose or glycerol. Metabolomics data showed significant increase of the products related to metabolic pathways in amino acid and energy metabolism in the mutant strain grown in glycerol. Genes such as glutamic acid decarboxylase (GAD) and some metabolites were both involved in the pathways such as GABAergic synapse. GAD1, GAD2, and succinate may be associated with the recombinant protein expression system of the mutant MF1 strain of P. pastoris grown on glucose or glycerol.

4-Aminobutyrate (GABA) is a nonproteinogenic amino acid that functions in stress tolerance and signaling. Here, we report that salinity stress and elevated GABA levels coincided with the induction of glutamate decarboxylase 4 (GAD4) expression in Arabidopsis thaliana (L.) Heynh. ecotype Col-0. In-silico and microarray analysis revealed the over-representation of binding sites for WRKY and MYB transcription factors in the GAD4 promoter, as well as their co-expression with GAD4. Transcript profiling of liquid culture-grown, wild-type plantlets subjected to salinity stress for up to two days confirmed that GAD4 expression is associated with the inducible co-expression of WRKY28, WRKY30, WRKY40, MYB2, MYB15, and MYB108, as well as calmodulin-like 37 and aluminum-activated malate transporter 2, suggesting the involvement of gene regulation, protein activation, and anion transport in GABA accumulation. Transcript profiling of shoots from soil-grown, wild-type plants and corresponding single and double GAD mutants subjected to two days of salinity stress suggests that the GABA accumulation could involve post-translational activation of pre-existing GAD1 and GAD2 by elevated cytosolic calmodulin, as well as induction of GAD4 expression.