Comprehensive analysis of transcription control factor complexes in a mouse brain cDNA library with c-Jun as a bait by using the cotranslation selection and screening of in vitro virus (IVV) and the C-terminal labeling method are conducted, thereby to provide known and unknown proteins which are unknown to form a complex with the c-Jun protein, whereby proteins that interact with c-Jun, nucleic acids encoding them and inhibitors utilizing them as well as methods for detecting an interaction and screening methods are provided.