Podocytes are terminally differentiated epithelial-derived cells that are responsible for blood filtration in the kidney. They exhibit a characteristic morphology with interdigitating foot-processes that are connected to the neighboring cell by specialized cell-cell junctions. These slit diaphragms (SD) act as selective filtration barrier that prevent larger particles such as proteins from entering the urinary space. Recent work indicates that SDs are mainly composed of two interacting proteins, Nephrin and Nephrin-like1 (NEPH1) that form multiple extracellular interactions via their immunoglobulin-like domains.
Our goal is to study the formation, dynamics and regulation of SDs by using a bottom up approach in heterotypic cell types that are not typically able to form such junctions. We will express fluorescently tagged fusion proteins of the key SD molecules in different combinations to determine the requirements for their correct expression, folding and surface delivery. We will also study the link of SD components to the actin cytoskeleton and in particular a role for cortical actin in SD stabilization.