1. Department of Anatomy, Biomedical Center, Faculty of Medicine, University of Iceland, Sturlugata 8, 102, Reykjavik, Iceland
2. Department of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
3. Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 102 Reykjavik, Iceland