Recently, we isolated a subset of glycolipoproteins from Panax ginseng, that we designated gintonin, and demon-strated that it induced [Ca2+]i transients in cells via G-protein-coupled receptor (GPCR) signaling pathway(s). However, active components responsible for Ca2+ mobili-zation and the corresponding receptor(s) were unknown. Active component(s) for [Ca2+]i transients of gintonin were analyzed by liquid chromatography-electrospray ioniza-tion-tandem mass spectrometry and ion-mobility mass spectrometry, respectively. The corresponding receptor(s) were investigated through gene expression assays. We found that gintonin contains LPA C18:2 and other LPAs. Proteomic analysis showed that ginseng major latex-like protein and ribonuclease-like storage proteins are protein components of gintonin. Gintonin induced [Ca2+]i tran-sients in B103 rat neuroblastoma cells transfected with human LPA receptors with high affinity in order of LPA2 > LPA5 > LPA1 > LPA3 > LPA4. The LPA1/LPA3 receptor antagonist Ki16425 blocked gintonin action in cells ex-pressing LPA1 or LPA3. Mutations of binding sites in the LPA3 receptor attenuated gintonin action. Gintonin acted via pertussis toxin (PTX)-sensitive and -insensitive G pro-tein-phospholipase C (PLC)-inositol 1,4,5-trisphosphate (IP3)- Ca2+ pathways. However, gintonin had no effects on other receptors examined. In human umbilical vein endothelial cells (HUVECs) gintonin stimulated cell proliferation and migration. Gintonin stimulated ERK1/2 phosphorylation. PTX blocked gintonin-mediated migration and ERK1/2 phosphorylation. In PC12 cells gintonin induced morpho-logical changes, which were blocked by Rho kinase inhibi-tor Y-27632. Gintonin contains GPCR ligand LPAs in com-plexes with ginseng proteins and could be useful in the development of drugs targeting LPA receptors.

Keywords: ginseng, gintonin, LPA-protein complexes, LPA receptors