A truncated version of sdk-1 that is unable to bind to MAGI-1 does not induce podocyte dysfunction when overexpressed. A, as shown in the schematic representation, sdk-1 ΔSSFV is identical to full-length sdk-1 except for a deletion of its last four amino acids. B, podocyte cell lines stably transfected with full-length sdk-1 or the truncated version express similar levels of sdk-1 protein. C, podocytes stably transfected with the full-length sdk-1 expression plasmid show dramatic loss of normal actin cytoskeletal structure characterized by a centrifugal distribution of actin filaments as determined by phalloidin staining as compared with podocytes expressing sdk-1 ΔSSFV. D, two blinded observers each counted from random fields the number of cells containing substantial stress fibers throughout the entire cell (in a non-centrifugal distribution). The percentage of positive cells was calculated per observer and then averaged (*, p < 0.01). Error bars indicate S.E.