1. Cell Signaling Research Group, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), E-08003 Barcelona, Spain
2. European Molecular Biology Laboratory, Genome Biology Unit, 69117 Heidelberg, Germany
3. Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
4. Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, IL 60611, USA