The present invention relates to methods for screening molecules and methods to detect protein-protein interactions and means used therein. More specifically, the present invention relates to methods for screening candidate drugs for treating or detecting MIF (macrophage migration inhibitor factor) related diseases. In certain aspects, the present invention involves detecting MIF/Jab1 (c-Jun activation domain binding protein) interactions as a basis for modulating cellular regulatory pathways and for identifying candidate drugs for MIF-related diseases. The invention also provides methods for the identification of molecules which dissociate or prevent interaction or binding between MIF and Jab1.