Fig. 1. (A) Enhancement of membrane cGMP levels following CNP-stimulation of natriuretic peptide receptor GC-B in untransfected and VILIP-1-transfected neural C6 cells. In VILIP-1-transfected glioma cells (C6-V1) and non-transfected C6 control cells (C6) cGMP accumulation was measured in unstimulated (Ctr) and CNP-stimulated (CNP, 0.2 µM) cells in the presence of the PDE inhibitor IBMX. (B) Time course of cGMP accumulation in non-transfected and VILIP-1-transfected C6 cells. Kinetic analysis of cGMP accumulation of non-transfected C6 cells (C6) and VILIP-1-transfected C6 cells (C6-V1) after CNP stimulation for various time points in the presence of IBMX. (C) Comparison of membrane cGMP levels following CNP-stimulation of natriuretic peptide receptor GC-B in untransfected, wild-type VILIP-1-, and myristoylation mutant-VILIP-1-transfected neural C6 cells. In wild-type VILIP-1-transfected glioma cells (C6-V1), myristoylation mutant VILIP-1-transfected (C6-V1M) and nontransfected C6 control cells (C6) cGMP accumulation was measured in unstimulated (Ctr) and CNP-stimulated (CNP, 0.2 µM) cells in the presence of the PDE inhibitor IBMX. (D) Expression of VILIP-1 and GC-B in non-transfected C6 and VILIP-1-transfected C6-V1 cells. Western blot analysis shows that no VILIP-1 expression can be detected in non-transfected C6 cells (lane 1), but can be detected as a 22 kDa protein in stably transfected C6-V1 cells (lane 2). The amount of GC-B protein with a M_r of 130 kDa (lanes 3, 4) does not differ between C6 cells (lane 3) and C6-V1 cells (lane 4) when compared with tubulin (50 kDa) as control. Mean values±s.d. are from two experiments for A and one representative experiment out of two for B and C carried out in triplicate.