Fig. 4. Concentration/response curves for the effects of SDF-1α and AMD3100 on GTPase activity in Sf9 membranes expressing CXCR4.
High-affinity GTPase activity was determined as described in Materials and Methods in Sf9 membrane 1182 (CXCR4 + Gαi2 + Gβ1γ2). A, Effects of SDF-1αand AMD3100 on basal GTPase activity. B, Inhibitory effect of AMD3100 on GTPase activity stimulated by SDF-1α (10 nM). Data shown are the means ± SD of a representative experiment performed in triplicates. Similar results were obtained in two independent experiments with different membrane preparations.