TABLE 5

Emax and EC50 values of ligand-stimulated [35S]GTPγS binding in N18TG2 cells with and without stable overexpression or knockdown of CRIP1a

Varying concentrations of WIN55,212-2 or MAEA were incubated with membranes prepared from the indicated cell lines in the presence of 20 μM GDP and 0.1 nM [35S]GTPγS, as described in Materials and Methods. Emax and EC50 values were derived from nonlinear regression analysis of ligand concentration-effect curves. Data are mean values ± S.E.M. (n = 5–9). Significance of Emax and EC50 values between cell types were determined by one-way ANOVA with posthoc Newman-Keuls test.

WIN55,212-2MAEA
Cell lineEmaxEC50EmaxEC50
% StimnM% StimnM
WT-N18TG245.1 ± 5.553.8 ± 12.240.1 ± 5.3497 ± 197
N18-CRIP1a-OX26.0 ± 3.5*82.5 ± 8.930.2 ± 3.5594 ± 178
N18-CRIP1a-KD64.0 ± 8.5*,§§40.9 ± 8.356.2 ± 5.3*,§322 ± 71
  • * P < 0.05 different from WT-N18TG2 cells. §P < 0.05, §§P < 0.01 different from N18-CRIP1a-OX cells.

  • Key: N18-CRIP1a-OX, N18TG2 cells overexpressing CRIP1a (clone 1); N18-CRIP1a-KD, N18TG2 cells with siRNA-mediated knockdown of CRIP1a (clone 2C).