Fig. 2

Overview of the heat shock response (HSR), from stress induction to the chaperoning action of heat shock proteins (HSPs). (A) HSR is activated by various stressors, including heat [30], cold [31], acid [32], base [33], inflammation [34, 35], increased reactive oxygen species [36, 37], heavy metals and toxins [38, 39], as well as mechanical stress [40]. (B) Stress triggers the trimerization of HSF1, which leads to its strong nuclear localization and increased DNA-binding capacity [16]. (C) Trimerized HSF1 binds the heat shock elements (HSEs) within target gene promoters, driving the transcription of HSP genes [1]. (D) HSPs, often in collaboration with co-chaperones, mitigate proteotoxic stress through diverse mechanisms, including protein repair, folding, degradation, transport, and complex formation. While a basal level of HSPs supports cellular housekeeping, the HSR significantly upregulates their inducible expression [41]