Table I. Rates of forward and reverse translocation of γ subunit types on activation of endogenous receptors in HeLa cells.
t1/2 values are in seconds. F - forward translocation. Increase in intracellular membrane FP-γ subunit fluorescence intensity on agonist activation was plotted and t1/2 determined. R- reverse translocation. Decrease in intracellular membrane FP-γ subunit fluorescence intensity on antagonist addition was plotted and t1/2 determined. CXCR4 receptors were activated with 100 ng/ml SDF-1α and deactivated with 20 µM AMD 3100. α2-AR receptors were activated with 10 µM norepinephrine and deactivated with 60 µM yohimbine.
| CXCR4 | α2-AR | CXCR4 | α2-AR | CXCR4 | α2-AR | |||
|---|---|---|---|---|---|---|---|---|
| γ9-F γ9-R |
10±2(10) 19±2 |
14±2(7) 19±4 |
γ5-F γ5-R |
66±5(5) 167± |
65±3(9) 127±8 |
γ8-F γ8-R |
123±5(6) 111±3 |
N.D. N.D. |
| γ1-F γ1-R |
20±1(6) 22±1 |
N.D. N.D. |
γ12-F γ12-R |
89±2(6) 104±4 |
61±3(10) 87±11 |
γ4-F γ4-R |
118±6(7) 143±19 |
N.D. N.D. |
| γ11F γ11-R |
36±3(7) 65±9 |
15±3(4) 28±1 |
γ10-F γ10-R |
95±3(8) 95±3 |
48±5(7) 60±9 |
γ2-F γ2-R |
161±13(6) 145±5 |
191±25(6) N.D. |
| γ7-F γ7-R |
45±1(5) 74±3 |
58±12(6) 100±27 |
γ13-F γ13-R |
100±2(7) 212±2 |
56±7(6) 53±3 |
γ3-F γ3-R |
286±17(10) 296±9 |
219±61(6) N.D. |
Mean ± SEM (no. of cells).
N.D. - not done. Cells were from multiple dishes.