Cell competition is driven by Xrp1-mediated phosphorylation of eukaryotic initiation factor 2α


生体から不良細胞を除去する「細胞競合」の仕組みの一端を解明 --不良細胞は小胞体ストレス応答機構を使ってタンパク質合成量を低下させ除去される--. 京都大学プレスリリース. 2021-12-08.Cell competition is a context-dependent cell elimination via cell-cell interaction whereby unfit cells (‘losers’) are eliminated from the tissue when confronted with fitter cells (‘winners’). Despite extensive studies, the mechanism that drives loser’s death and its physiological triggers remained elusive. Here, through a genetic screen in Drosophila, we find that endoplasmic reticulum (ER) stress causes cell competition. Mechanistically, ER stress upregulates the bZIP transcription factor Xrp1, which promotes phosphorylation of the eukaryotic translation initiation factor eIF2α via the kinase PERK, leading to cell elimination. Surprisingly, our genetic data show that different cell competition triggers such as ribosomal protein mutations or RNA helicase Hel25E mutations converge on upregulation of Xrp1, which leads to phosphorylation of eIF2α and thus causes reduction in global protein synthesis and apoptosis when confronted with wild-type cells. These findings not only uncover a core pathway of cell competition but also open the way to understanding the physiological triggers of cell competition

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