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  • The functional role of Ire1...
    Das, Eshita; Sahu, Kiran Kumari; Roy, Ipsita

    The FEBS journal, June 2023, 2023-Jun, 2023-06-00, 20230601, Letnik: 290, Številka: 12
    Journal Article

    Inhibition of endoribonuclease/kinase Ire1 has shown beneficial effects in many proteotoxicity‐induced pathology models. The mechanism by which this occurs has not been elucidated completely. Using a proteotoxic yeast model of Huntington's disease, we show that the deletion of Ire1 led to lower protein aggregation at longer time points. The rate of protein degradation was higher in ΔIre1 cells. We monitored the two major protein degradation mechanisms in the cell. The increase in expression of Rpn4, coding for the transcription factor controlling proteasome biogenesis, was higher in ΔIre1 cells. The chymotrypsin‐like proteasomal activity was also significantly enhanced in these cells at later time points of aggregation. The gene and protein expression levels of the autophagy gene Atg8 were higher in ΔIre1 than in wild‐type cells. Significant increase in autophagy flux was also seen in ΔIre1 cells at later time points of aggregation. The results suggest that the deletion of Ire1 activates UPR‐independent arms of the proteostasis network, especially under conditions of aggravated stress. Thus, the inhibition of Ire1 may regulate UPR‐independent cellular stress‐response pathways under prolonged stress. The role of endoribonuclease/kinase Ire1 in cellular proteostasis has been investigated. Deletion of Ire1 led to lower protein aggregation at longer time points in a yeast model of Huntington's disease. Activation of unfolded protein response (UPR)‐independent arms of the proteostasis network was observed under conditions of aggravated stress. Proteasomal activity and autophagy were enhanced. Thus, the inhibition of Ire1 may regulate UPR‐independent cellular stress‐response pathways under prolonged stress.