Modulation of GCN2 activity under excess light stress by osmoprotectants and amino acids

The protein kinase GCN2 (General Control Nonderepressible2) and its phosphorylation target, the eukaryotic translation initiation factor (eIF)2 alpha represent the core module of the plant's integrated stress response, a signaling pathway widely conserved in eukaryotes that can rapidly regulate translation in response to stressful conditions. Recent findings indicate that the Arabidopsis thatiana GCN2 protein operates under the command of reactive oxygen species (ROS) emanating from the chloroplast under a variety of abiotic stresses such as excess light. To get deeper insights into the mechanism of GCN2 activation under excess light, we assessed the role of amino acids in view of the classic function of GCN2 as a sensor of amino acid status. Additionally, given that osmoprotectants can counteract ROS-related stresses, we tested their ability to mitigate GCN2 activity. Our results demonstrate that certain amino acids and osmoprotectants attenuate eIF2 alpha-phosphorylation under excess light stress to some degree. Future investigations into the biochemical mechanisms of these natural compounds on GCN2 signaling activity will provide better insights into the GCN2-eIF2 alpha regulation.

Automated summary

The protein kinase GCN2 and its phosphorylation target eIF2 alpha play a key role in the plant's integrated stress response, regulating translation under stressful conditions. Recent studies show that GCN2 in Arabidopsis is controlled by reactive oxygen species from the chloroplast under various abiotic stresses like excess light.