Figure 3.

Calcium signaling was induced by gp120 and blocked by pertussis toxin, U73122, and anti-Bob antibodies. Treatment with gp120_IIIB (50 pmol/L in Locke’s buffer) induced an immediate calcium signal (A). Similar signals (not shown) were seen with gp120_CM235 (10 nmol/L). No significant gp120_IIIB-induced calcium signaling was seen after pretreatment with pertussis toxin (500 ng/ml for 18 hours) (B) or U73122 (10 μmol/L for 30 minutes) (C). U73343, an inactive analog of U73122, had no inhibitory effect (data not shown). Anti-Bob37 (100 μg/ml for 18 hours) also inhibited the gp120_IIIB-induced calcium signaling (D). These cells were then treated with SDF-1, causing a substantial calcium signal (E). Calcium signals were observed in Ghost (3) cell Bob cells with 15 fmol/L gp120_IIIB (F). Original magnifications, ×160.