title: AKT-independent Reelin signaling requires interactions of heterotrimeric Go and Src.
abstract: Reelin, a large secreted extracellular matrix glycoprotein, plays a key role in neuronal migration during cortical development and promotes neuronal maturation. The signaling pathway regulating neuronal maturation in the postnatal period are relatively less well understood. In this study, we demonstrated that a heterotrimeric G protein, Go, is a novel target of Reelin-induced signaling to promote neurite outgrowth. In primary hippocampal neurons of Reelin-deficient reeler mice, neurite outgrowth was significantly reduced and rescued upon addition of Reelin. Pertussis toxin (PTX) treatment or transfection with Gαo-siRNA suppressed Reelin-mediated neurite outgrowth in wild-type neurons. Additionally, Reelin treatment led to increased phosphorylation of AKT, GSK3β, and JNK, which were all effectively blocked by the PI3K inhibitor, LY294002. By comparison, PTX specifically blocked JNK activation, but not AKT and GSK3β. Immunoprecipitation assays disclosed that Reelin increases the active forms of both Src and Gαo and promotes their direct association. Notably, Dab1, a cytoplasmic adaptor molecule that mediates Reelin signaling, did not interact with Gαo. Neurite outgrowth by Reelin was induced via activating Src kinase, which directly stimulated Gαo, activity, leading to JNK activation. Based on the collective findings, we suggest that Reelin-dependent signaling mechanisms may be split into Src-AKT-dependent and Src-Go-dependent pathways. Our results additionally provide evidence that Reelin receptors cross-communicate with heterologous G protein-coupled receptors (GPCR) independently of the cognate ligands of GPCR.
authors.affiliation: Department of Anatomy, Ajou University School of Medicine, Suwon 16499, South Korea; Center for Cell Death Regulating Bio-drug, Ajou University School of Medicine, Suwon 16499, South Korea.
authors.forename: Sung-Kuk
authors.initials: SK
authors.lastname: Cho
authors.affiliation: Department of Anatomy, Ajou University School of Medicine, Suwon 16499, South Korea.
authors.forename: Jung-Mi
authors.initials: JM
authors.lastname: Choi
authors.affiliation: Department of Anatomy, Ajou University School of Medicine, Suwon 16499, South Korea; Center for Cell Death Regulating Bio-drug, Ajou University School of Medicine, Suwon 16499, South Korea.
authors.forename: Jong-Mu
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Deparment of Genetic Engineering, Sungkyunkwan University, Suwon 16419, South Korea.
authors.forename: Jae Youl
authors.initials: JY
authors.lastname: Cho
authors.affiliation: Department of Anatomy, Ajou University School of Medicine, Suwon 16499, South Korea.
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Kim
authors.affiliation: Deparment of Genetic Engineering, Sungkyunkwan University, Suwon 16419, South Korea.
authors.forename: Sungyoul
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Anatomy, Ajou University School of Medicine, Suwon 16499, South Korea. Electronic address: hysuh@ajou.ac.kr.
authors.forename: Haeyoung
authors.initials: H
authors.lastname: Suh-Kim
authors.affiliation: Department of Anatomy, Ajou University School of Medicine, Suwon 16499, South Korea; Center for Cell Death Regulating Bio-drug, Ajou University School of Medicine, Suwon 16499, South Korea. Electronic address: ydl1217@ajou.ac.kr.
authors.forename: Young-Don
authors.initials: YD
authors.lastname: Lee
mesh_terms: D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D000091042:Reelin Protein; D012697:Serine Endopeptidases / Q000378:metabolism*; D015398:Signal Transduction; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D000091042:Reelin Protein; D019061:src-Family Kinases; D051057:Proto-Oncogene Proteins c-akt; C000717128:Reln protein, mouse; D012697:Serine Endopeptidases; D020962:Heterotrimeric GTP-Binding Proteins
keywords: Dab1; Gα(i/o); Neurite outgrowth; Reelin; Src