PRT4165 is primarily used in biochemical and pharmaceutical research as a selective inhibitor of the RNF43/ZNRF3 E3 ubiquitin ligases, which play key roles in regulating the Wnt signaling pathway. By inhibiting these ligases, PRT4165 stabilizes Wnt receptors on the cell surface, leading to enhanced Wnt pathway activation. This property makes it a valuable tool in studies related to stem cell biology, tissue regeneration, and cancer research, particularly in models where Wnt signaling is suppressed. It is commonly applied in in vitro systems to modulate Wnt activity and investigate downstream cellular responses such as proliferation, differentiation, and self-renewal. Its use supports the development of targeted therapies for diseases involving dysregulated Wnt signaling, including certain gastrointestinal and liver cancers.