1986-1989 Ph.D. student, Spanish Research Council, CID-CSIC, Barcelona, Spain. 1990-1991 Postdoctoral fellow of the Spanish Research Council, CID-CSIC, Barcelona, Spain. 1991-1993 Human Frontiers and Science Program postdoctoral fellow. The Center for Blood Research and Harvard Medical School, Boston, MA. 1994-1997 Research Associate, The Center for Blood Research and Harvard Medical School, Boston, MA. 1997-2002 Group leader, Karolinska Institute, Department of Biosciences at NOVUM, Huddinge, Sweden. 2002-2009 Group leader, Spanish Research Council, CNB-CSIC, Madrid, Spain. 2010- Professor, Spanish Research Council, CNB-CSIC, Madrid, Spain.