Hsp70 and Hsp60 Chaperone Mechanisms: Orchestrating Proteostasis in Health and Disease

This article provides a comprehensive analysis of the Hsp70 and Hsp60 molecular chaperone systems, which are fundamental to maintaining cellular protein homeostasis (proteostasis). It elucidates their distinct structural and mechanistic strategies for managing client proteins. The Hsp70 system acts as a central triage hub, featuring a nucleotide-binding domain (NBD) and a substrate-binding domain (SBD) whose functions are coupled through a bidirectional allosteric mechanism. This ATP-driven cycle, tightly regulated by J-domain proteins and nucleotide exchange factors, allows Hsp70 to transiently bind hydrophobic segments of client proteins, deciding their fate between folding, trafficking, or degradation. In contrast, the Hsp60 chaperonin system, exemplified by mitochondrial Hsp60 and its co-chaperone Hsp10, forms a large, double-ring oligomeric complex. This structure creates an isolated "Anfinsen cage" that encapsulates entire unfolded proteins, providing a protected environment for them to fold without aggregating. The review details the dysregulation of these chaperone networks in human pathologies. In cancer, chaperones are often overexpressed and form pathological "epichaperome" assemblies that rewire cellular networks to support malignancy. In neurodegenerative diseases, chaperone systems become overwhelmed, leading to the accumulation of toxic protein aggregates. The article also explores the challenges and evolution of therapeutic strategies. Initial efforts focused on ATP-competitive inhibitors, but these were hampered by issues of isoform selectivity, functional redundancy, and toxicity. Advanced strategies now target less conserved allosteric sites and specific protein-protein interactions to achieve greater specificity. Advanced research methodologies, including cryo-EM, X-ray crystallography, and high-throughput screening platforms, are crucial for advancing these therapeutic endeavors. Source: https://www.proteinqc.com/posts/hsp70-and-hsp60-chaperone-mechanisms-orchestrating-proteostasis-in-health-and-disease