Prof. Janssen is Head of the Molecular Immunology Group at the Institute for Immunology. Since 1995, Prof. Janssen chairs the DGfI Study Group Signal Transduction. Since 2012, he serves as coordinator of the DGfI study groups. He has been nominated as a Co-Organizer of the annual Spring School on Immunology and served as Chair of the Adaptive Immunity Session from 2005-2008. Prof. Janssen established the Signal Transduction Society and served as President an Vice-President for more than 10 years. He established and co-organized the successful Meeting Series "Signal Transduction- Receptors, Mediators and Genes" and since August 2008, he is an Associate Editor of the BMC Open Access Journal "Cell Communication and Signaling"