Miwa Tsukumi, Taguchi Hideki
Cell Biology Center, Institute of Integrated Research, Institute of Science Tokyo (Formerly Tokyo Institute of Technology), S2-19, Nagatsuta 4259, Midori-ku, Yokohama, 226-8501, Japan.
Biol Chem. 2025 Jan 7;406(1-2):29-33. doi: 10.1515/hsz-2024-0140. Print 2025 Jan 29.
The heat stress response is an essential defense mechanism in all organisms. Heat shock proteins (Hsps) are produced in response to thermal stress, with their expression levels regulated by heat shock transcription factors. In the key transcription factor σ positively regulates Hsp expression. Studies from over two decades ago revealed that σ abundance is negatively controlled under normal conditions, mainly through degradation mechanisms involving DnaK, GroEL, and FtsH. Beyond this established mechanism, recent findings indicate that a small heat shock protein IbpA also plays a role in the translational regulation of σ, adding a new layer to the established model. This review highlights the role of a new actor, IbpA, which strongly suppresses σ expression under non-stress conditions and markedly increases it during heat shock.
热应激反应是所有生物体中一种重要的防御机制。热休克蛋白（Hsps）是在热应激反应中产生的，其表达水平受热休克转录因子调控。在 中，关键转录因子σ正向调节Hsp的表达。二十多年前的研究表明，在正常条件下，σ的丰度受到负调控，主要通过涉及DnaK、GroEL和FtsH的降解机制。除了这种已确立的机制外，最近的研究结果表明，一种小热休克蛋白IbpA在σ的翻译调控中也发挥作用，为已确立的模型增添了新的层面。本综述重点介绍了新角色IbpA的作用，它在非应激条件下强烈抑制σ的表达，而在热休克期间显著增加其表达。
