The main interests of our cell biology lab are focused on the interplay between cell signaling and protein trafficking. Recently we have discovered a number of new molecules involved in G-protein mediated signaling pathways, including GAIP, RGS-PX1, GIPC and calnuc. These new proteins serve to modulate G protein signaling and to link G protein signaling to growth factor receptor trafficking. To define the molecular mechanisms involved we are using a combination of molecular (yeast two hybrid, phage display), proteomics (mass spec), biochemical (cell fractionation, in vitro assays), bioinformatics, and morphologic (immunofluorescence, immunoelectron microscopy, confocal and deconvolution microscopy) approaches to study a variety of mammalian systems including cells in culture, mouse mutants and mammalian tissues. Another long standing interest of our lab is in understanding the cellular and molecular mechanisms of glomerular filtration and protein absorption under normal and pathogenic conditions. Our current research in this area focuses on trafficking and signaling of megalin-- an endocytic receptor involved in protein absorption and signaling, the role of podocalyxin in the regulation of the podocyte's architecture in normal and nephrotic animals and the interactions and pathology of nephrin.