Our study reveals that the reduction of HSP90B1 in human 293T cells leads to increased ROS production, JNK activation, and apoptosis, while transgenic expression of HSP90B1 inhibits these processes in Drosophila. Additionally, we observed a decrease in Gp93 mRNA levels in aging fly brains, suggesting that human HSP90B1 may serve as a biomarker for the early stages of neurodegenerative diseases. The gene discussed is MAPK8; the disease is neurodegenerative disease.