Fig. 6.

Alterations of G protein content and cAMP formation in NDPK A/B double-knockout and Gβ subunit knockdown MEFs. (A) Membrane fraction of mouse embryonic fibroblasts (MEFs) from wild-type (WT), heterozygous (+/−), and homozygous (−/−) NDPK A/B mice were subjected to immunoblot analysis with the indicated antibodies, showing the loss of G protein α and β subunits as well as caveolin-1 in the membrane fraction of NDPK A/B KO MEFs. Positions of Gα_s splice variants (long, α_sL, short, α_sS) are indicated. (B) Basal cAMP production in WT, (+/−) and (−/−) NDPK A/B MEFs in the presence of 1 mM IBMX and 1 μM propranolol. Data are means ± SEM, n = 3, *, P < 0.05 vs. WT. (C) Immunoblot analysis of WT MEFs transfected with scrambled siRNA (si-Ctrl) and specific siRNA (si-) against Gβ₁ and Gβ₂ as indicated, demonstrating reduced expression of NDPK B and caveolin-1 in MEFs following Gβ₁ or Gβ₂ depletion. Expression levels of β-actin served as loading control. (D) Basal cAMP contents were measured 72 h after transfection with the indicated siRNA in the presence of 1 mM IBMX and 1 μM propranolol. Data are means ± SEM, n = 3, *, P < 0.05 vs. si-Ctrl.