(A) Podocytes were treated with Rp-cAMPs or U0126, or transfected with PKA-insensitive PTP-SL-S231A mutant, and then stimulated with 10 μM isoproterenol (ISO). Synaptopodin mRNA abundance was quantified using RT-PCR and normalized against the amount of tubulin mRNA (all values are means ± SEM; *P < 0.001, one-way ANOVA; n = 3). (B) Cells transfected with dominant-negative K-CREB (or empty vector) and stimulated with 10 μM isoproterenol. Isoproterenol stimulation led to no change in synaptopodin expression in the K-CREB group, where significant increase was observed in vector-transfected cells (*P < 0.001, one-way ANOVA; n = 3). (C) Representative immunofluorescence images of cultured podocytes that have been treated with 10 μM isoproterenol. Colocalization of synaptopodin (green pseudocolor) with actin bundles (red pseudocolor) is indicated with a yellow arrow. Red arrow indicates loss of bundling in cells treated with isoproterenol and Rp-cAMPs. Scale bar, 50 μm. (D) Quantification of immunofluorescence images in (C) (*P < 0.05, one-way ANOVA; n = 18 cells over five slides in two experiments).