HSP

Heat shock proteins (HSPs) are molecular chaperones that support proteostasis by preventing protein misfolding and aggregation during nascent-chain folding and cellular stress^[1]. Mechanistically, HSP70 acts upstream on nascent and newly synthesized polypeptides, while HSP90 supports folding and maturation of selected client proteins through coordinated chaperone cycles^[1][2]. In cancer models, HSP90 buffers oncogenic signaling proteins and enables malignant cells to tolerate imbalanced signaling, making HSP90 inhibition a practical strategy for disrupting multiple client pathways^[3][4]. Compared with ATP-dependent HSP70/HSP90 systems, HSP27/HSPB1 is a small heat shock protein whose oligomer-monomer dynamics regulate chaperone activity and whose redox-sensitive monomers suppress aggregation in vitro^[5]. HSP27 also regulates apoptosis by interacting with cytochrome c and blocking downstream apoptotic complex formation, supporting its use in cell-death and stress-response experiments^[6]. For experimental applications, HSP90 inhibitors provide tools to test client-protein dependence, while HSP27-focused assays can examine aggregation control, redox stress, and apoptosis regulation^[4][5][6].