Table 2.

Effects of phorbol ester on CD4 endocytosis and phosphate incorporation

Construct	Endocytosis ratea			Relative phosphate incorporationb
	−PMA (%/min)	+PMA (%/min)	+PMA:−PMA	−PMA	+PMA	+PMA:−PMA
wtCD4	5 ± 0.9	19.2  ± 3.3	3.8	1	6.1	6.1
	n = 11	n = 8		n = 7	n = 7
K418	4.2  ± 0.9	18.2  ± 3.4	4.3	1.2	6.3	5.2
	n = 3	n = 3		n = 7	n = 7
R412	2.4  ± 0.2	2.3  ± 0.4	1	0.9	4.4	4.9
	n = 3	n = 3		n = 1	n = 1
H399	1.2  ± 0.4	1.0  ± 0.2	1	NDc	ND
	n = 10	n = 8
Mutations in K418 background
K418 S408A/S415A	1.7  ± 1.0	4.2  ± 0.2	2.4	ND	ND
	n = 3	n = 4
K418 S408E/S415E	1.9  ± 0.8	4.1  ± 0.1	2.2	ND	ND
	n = 3	n = 3
K418 S408A	1.7  ± 1.0	7.1  ± 1.7	4.1	0.7	4.0	5.7
	n = 3	n = 3		n = 4	n = 4
K418 S408E	2.7  ± 0.5	13.7  ± 4.5	5	2.0	8.3	4.1
	n = 7	n = 7		n = 3	n = 3
K418 S415A	2.1  ± 0.4	6.6  ± 1.2	3.1	0.1	2.4	24
	n = 3	n = 3		n = 1	n = 1
K418 S415E	2.0  ± 0.3	5.0  ± 0.6	2.5	0.1	2.5	25
	n = 3	n = 2		n = 2	n = 2
K418 L413A/L414A	2.2  ± 0.7	2.5  ± 0.4	1	1.1	7.1	6.5
	n = 4	n = 3		n = 3	n = 3
K418 L413V	1.6  ± 0.4	1.9  ± 0.2	1	2.7	5.9	0.5
	n = 2	n = 3		n = 2	n = 1
K418 L413V/L414V	1.9  ± 0.5	2.3  ± 0.4	1	1.7	7.3	4.4
	n = 2	n = 3		n = 1	n = 1

^aEndocytosis rates were normally calculated over the first 4 min after warmup except in PE-treated cells. Because the effects of PE were observed after a lag of ∼1 min (see Fig. 2A), the rates for these cells were calculated 1–4 min after warmup. The effects of PE on CD4 endocytosis are given as the ratio of the rates +PMA:−PMA. 

^bPhosphate incorporation for each construct (− and +PMA) is compared with wt CD4 immunoprecipitated from untreated cells (see MATERIALS AND METHODS). Wild-type CD4 is set to 1. n, number of experimental data sets used in these calculations. 

^cND, not detected.