Dictyostelium cells bind a secreted autocrine factor that represses cell proliferation

BMC Biochemistry

Table 1 rAprA and wild-type conditioned growth medium slow the proliferation of wild-type (WT) and aprA^- cells.

	rAprA		WT conditioned growth medium (CGM)
Cell type	Activity, units/μg	Proliferation as percent of control at high rAprA	Activity, units/ml	Proliferation as percent of control at high CGM	Activity, units/μg AprA
WT	3.7 ± 0.9	71 ± 1	1.5 ± 0.5	64 ± 8	4.9 ± 1.7
*aprA* ^-	10.7 ± 2.8	70 ± 1	1.4 ± 0.5	60 ± 6	4.5 ± 1.7
*cfaD* ^-	0 ± 0	97 ± 1	ND	ND	ND
*crlA* ^-	0 ± 0	97 ± 1	ND	ND	ND

Cells of the indicated strain were grown in the presence of different concentrations of rAprA, and cells were counted after 12 hours. After fitting sigmoidal dose response curves (Figure 2), the activity of rAprA and the proliferation as a percent of control at high concentrations of rAprA were calculated. Similar fits were done for cells grown in different dilutions of wild-type conditioned growth medium (Figure 3). The activity of the AprA in conditioned growth medium was calculated using the observed AprA concentration of 0.3 μg/ml. All values are mean ± SEM from 3 independent experiments. ND indicates not determined.

ISSN: 1471-2091