My research focusses on the function of the PKD1 gene family. Mutations in PKD1 cause autosomal dominant polycystic kidney disease (ADPKD). PKD1 encodes polycystin-1, a large cell-surface protein of unknown function. Using biochemical, molecular and structural techniques we aim to identify extracellular and intracellular ligands and show how they interact with protein domains found in polycystin-1. In addition, mechanisms that target polycystin-1 to the cell surface are being identified. The polycystins have been shown to function as mechanosensitive calcium channels localised to the renal primary cilium. We have shown that members of the classical receptor protein tyrosine phosphatase family interact with the polycystins in the primary cilium. This identifies a novel mechanism for mechanoregulation of ion channel function. Elucidation of the normal function of polycystin-1 will identify key steps in the pathogenesis of ADPKD and potential ways of modifying disease progression.