Skip to main content
. 2010 Jan 4;285(10):7805–7817. doi: 10.1074/jbc.M109.091173

FIGURE 4.

FIGURE 4.

GRK6 contributes to Ser-324/5 phosphorylation after CXCL12 stimulation. A, shown is a representative Western blot (WB) demonstrating specific and efficient knockdown of GRKs endogenously expressed in HEK293 cells 72 h post-transfection. B, knockdown of GRK6, but not GRK2, GRK3, or GRK5 led to a significant reduction in phosphorylation of Ser-324/5. Left panel, shown is a representative Western blot using purified anti-Ser(P)-324/5. Right panel, shown is a comparison of Ser(P)-324/5 phosphorylation after a 5-min stimulation with CXCL12. Ser(P)-324/5 was normalized to total CXCR4, and data are presented as the percent of control at 5 min (±S.E., n = 4). C, GRK6 knockdown and PKC inhibition almost completely abolished phosphorylation of Ser-324/5. Cells transfected with GRK6 siRNA were pretreated with 2.5 μm Bis I or Bis V 30 min before stimulation with CXCL12. Left panel, shown is a representative Western blot using purified anti-Ser(P)-324/5. Right panel, Ser(P)-324/5 was normalized to total CXCR4, and data are presented as -fold increase over basal in control/Bis V-treated cells (±S.E., n = 3; *. p ≤ 0.05; **, p ≤ 0.01; ***, p ≤ 0.001).