Many Thanks also to… …the whole PEX-lab group for the nice working atmosphere and all the scientific and nonscientific discussions. I especially thank Jenny Günther, the good soul of the group, for her comprehensive and patient help with technical issues. …the EM facility, Torben Ruhwedel, Dr. Wiebke Möbius and Boguslawa Sadowski for teaching and helping me a lot with the electron microscopy. …Dr. Judith Blanz and Meryem Senkara for their great help with lysosomal enzyme assays and providing antibodies. I'm especially grateful for welcoming and teaching me this technique. …Dr. Britta Brügger for her collaboration and doing lipid mass spectrometry. …Dr. Rhona McGonigal and Prof. Hugh Willison for providing antibodies and their great technical and theoretical support regarding gangliosides. …Dr. Livia de Hoz for advices and analysis of electrophysiological data. …Prof. Myriam Baes for her collaboration and providing mice. …Dr. Susanne Quintes, Dr. Theresa Kungl, and Dr. Julia Patzig for their advices and help concerning PNS biology. …Annette Fahrenholz, Ramona Jung, and Ulli Bode for technical help in many ways. …the animal caretakers for looking after my mice and thereby providing the basis of this work. …Michaela Schmalstieg and Gabriele Endo for organizational help. …Lothar Demel, Hans-Joachim Horn, Rolf Merker, and Harry Scherer for technical help concerning IT issues. …the whole Neurogenetics department for the great working atmosphere. I especially want to thank Sina, Jenny, Sarah, Dinah, Tim, and Jan for the great time in the lab and all the fun we had during the retreats. Abschließend geht ein großer Dank an meine Familie, die mich immer unterstützt hat und ohne die dies alles nicht möglich gewesen wäre. Ein besonderer Dank geht an Andreas Schmidt, der mir immer zu Seite stand und auch in schwierigen Phasen immer die richtigen Worte gefunden hat um mich zu motivieren. Content List of figures .