A Dictyostelium chalone uses G proteins to regulate proliferation

Table 4 Binding kinetics of rAprA to cells

Cell type	K_D, μg/ml	K_D, nM	Bmax, ng/5 × 10⁵ cells	Bmax, molecules/cell
Wild-type	0.16 ± 0.05	2.7 ± 0.8	3.1 ± 0.4	62,000 ± 8,000
gα5 ^-	0.54 ± 0.21	9.0 ± 3.5	2.6 ± 0.4	52,000 ± 10,000
gα8 ^-	0.56 ± 0.28	9.3 ± 4.7	3.8 ± 0.9	76,000 ± 18,000
gα9 ^-	0.16 ± 0.06	2.7 ± 1.0	0.7 ± 0.1*	14,000 ± 2,000*
gβ ^-	0.85 ± 0.33	14.2 ± 5.5	1.0 ± 0.2*	20,000 ± 4,000*

For the indicated cell lines, the K_D in μg/ml and the Bmax in ng/5 × 10⁵ cells was obtained from the curve fits in Fig 4. The K_D in nM and Bmax in molecules/cell were calculated using a molecular mass of 60 kDa for rAprA. All values are mean ± SEM, n = 3. A * after a value indicates that the value was significantly different from the wild-type value with p < 0.05 (1-way ANOVA, Dunnett's test).

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