1 Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.
2 Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; nikolaus.pfanner@biochemie.uni-freiburg.de.
3 BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.