Involved in oxidative stress response and redox homeostasis. Required for hydrogen peroxide-induced oxidation and nuclear localization (activation) of YAP1. Functions probably in concert with HYP1/GPX3, the actual YAP1 modifying enzyme. YBP1 is not required for HYP1/GPX3-independent, diamide-induced oxidation of YAP1. Interacts with YAP1. Forms a peroxide stress induced complex with YAP1 in the cytoplasm. Systematic proteome-wide 2-hybrid interaction studies suggest that YAP1, HYR1/GPX3, and YBP1 all interact with the nuclear pore complex subunit NUP116, which is involved in nucleocytoplasmic transport. Present with 3100 molecules/cell in log phase SD medium. Belongs to the YBP1 family. YBP1 encoded by the widely used laboratory strain W303-1a is only partially functional, probably due to four amino acid substitutions.