Heat shock protein 70 in Cynops orientalis: bidirectional thermal regulation and metabolic optimization in amphibian climatic adaptation

This study investigates the molecular mechanisms underlying thermal resilience in the Cynops orientalis (Chinese fire-bellied newt) through functional characterization of CoHsp70, a cytosolic heat shock protein 70 homolog. Comparative genomic analysis revealed conserved structural domains (ATPase, substrate-binding domain, and EEVD motif) and > 80% sequence identity with amphibian orthologs. Tissue-specific profiling identified fat tissue as the predominant site of CoHsp70 expression. Temperature-dependent transcriptional regulation exhibited bidirectional dynamics: rapid induction under acute heat stress versus progressive suppression during chronic cold exposure. CoHsp70 overexpression enhanced hyperthermic survival while reducing metabolic expenditure (SMR, REE) and oxygen consumption rate (OCR). Taken together, these results suggest that CoHsp70 is a critical modulator of amphibian temperature resilience, balancing proteostatic fidelity with energy conservation under thermal extremes.