Peter Deen is a molecular cell biologist interested in the physiology of the renal vasopressin V2 receptor and Aquaporin (AQP) water channels in health and disease. During the last decade, his team cloned the several renal AQPs and was, in collaboration with other groups, the first to identify mutations in the AQP2 gene, leading to Nephrogenic Diabetes Insipidus (NDI), a disease in which humans can not concentrate their urine and consequently void 10-15 liters of urine daily. By expression of the encoded mutant AQP2 proteins in oocytes and MDCK cells, his team has been able to decipher the underlying mechanisms causing recessive and dominant NDI. At present, his research also focuses on elements and proteins involved in the routing of AQP2, resolving its structure and identifying inhibitors of this channel. For his research, he obtained a KNAW fellowship and was the first European recipient of the prestigious Young Investigator Award of the American Physiological Society in 2001. In May 2010, he was promoted to full professor in Cellular Physiology.