Calcium signaling inhibitors but not PTX block gp120-induced tyrosine phosphorylation of Pyk2.

MDMs were exposed for 5 minutes to JRFL gp120 (2.5 μg/mL) following (A) pretreatment for 20 minutes with or without 2 mM EGTA or (B) following pretreatment for 20 minutes with 100 nM lanthanum or for 18 hours with 100 ng/mL PTX. Whole cell lysates were then analyzed by immunoblotting with an antibody specific for the phosphorylated form of Pyk2 (upper panels, P-Pyk2) or with an antibody specific for total Pyk2 (lower panels). Blots shown are representative of 4 independent experiments using different donors.