A, ghrelin induces membrane ruffling and actin polymerization in U-87 cells. Cells were fixed, permeabilized, and stained with Alexa Fluor 488-labeled phalloidin 20 min after ghrelin treatment (100 ng/ml). B, ghrelin treatment induces a time-dependent increase in PKC phosphorylation in U-87 cells. pPKC, phospho-PKC; T-PKC, total PKC. C, ghrelin elicits intracellular calcium release in control (C) scrambled siRNA-transfected U-87 cells, but not in cells subjected to GHS-R silencing by RNA interference. FL, fluorescence. D, ghrelin activates PKC via a GHS-R-dependent pathway. There was an increase in PKC phosphorylation 10 min after ghrelin treatment in cells transfected with control siRNA, but no induction in GHS-R siRNA-transfected U-87 cells.