IU1 is a selective, reversible USP14 inhibitor with an IC50 of 4-5 μM. IU1 binds USP14’s catalytic cleft to block deubiquitinase activity. IU1 induces calpain-dependent Tau cleavage, causes ATP deficits, reduces E1~Ub thioester levels and 26S proteasome assembly. IU1 enhances 26S proteasome chymotrypsin-like activity, modulates LC3B-dependent autophagy flux, reduces cancer cell proliferation and migration, and blocks G0/G1 to S phase cell cycle transition in follicular thyroid cancer cells. IU1 activates autophagy-lysosomal and ubiquitin-proteasome pathways, triggers apoptosis, and reduces cervical cancer cell growth. IU1 enhances degradation of proteasome substrates linked to neurodegenerative disease, accelerates oxidized protein degradation, and increases oxidative stress resistance. IU1 can be used for the research of Alzheimer’s disease, follicular thyroid cancer, ischemic stroke, cervical cancer, and neurodegenerative disease .
