FIGURE 1.

PDE expression pattern in MEF cells. A, PDE activity in detergent extracts prepared from wild type MEFs was measured in the absence or presence of the PDE4-selective inhibitor rolipram and the PDE3-selective inhibitor milrinone to determine the contribution of PDE4 and PDE3 to the overall PDE activity, respectively. B and C, detergent extracts prepared from wild type MEFs were subjected to immunoprecipitation with PDE4 subtype-selective (B) or PDE4D variant-selective antibodies (C). The PDE activity recovered in the IP pellets was corrected for the amount of protein used as IP input. All data represent means ± S.E. of at least three experiments. C, inset, 50 μg of detergent extract prepared from wild type and PDE4DKO MEFs was separated on SDS-PAGE and probed in Western blotting using α-PAN-PDE4D (Icos4D) antibody.