title: Slit2 inactivates GSK3β to signal neurite outgrowth inhibition.
abstract: Slit molecules comprise one of the four canonical families of axon guidance cues that steer the growth cone in the developing nervous system. Apart from their role in axon pathfinding, emerging lines of evidence suggest that a wide range of cellular processes are regulated by Slit, ranging from branch formation and fasciculation during neurite outgrowth to tumor progression and to angiogenesis. However, the molecular and cellular mechanisms downstream of Slit remain largely unknown, in part, because of a lack of a readily manipulatable system that produces easily identifiable traits in response to Slit. The present study demonstrates the feasibility of using the cell line CAD as an assay system to dissect the signaling pathways triggered by Slit. Here, we show that CAD cells express receptors for Slit (Robo1 and Robo2) and that CAD cells respond to nanomolar concentrations of Slit2 by markedly decelerating the rate of process extension. Using this system, we reveal that Slit2 inactivates GSK3β and that inhibition of GSK3β is required for Slit2 to inhibit process outgrowth. Furthermore, we show that Slit2 induces GSK3β phosphorylation and inhibits neurite outgrowth in adult dorsal root ganglion neurons, validating Slit2 signaling in primary neurons. Given that CAD cells can be conveniently manipulated using standard molecular biological methods and that the process extension phenotype regulated by Slit2 can be readily traced and quantified, the use of a cell line CAD will facilitate the identification of downstream effectors and elucidation of signaling cascade triggered by Slit.
authors.affiliation: Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Byun
authors.forename: Bo Taek
authors.initials: BT
authors.lastname: Kim
authors.forename: Yun Tai
authors.initials: YT
authors.lastname: Kim
authors.forename: Zhongxian
authors.initials: Z
authors.lastname: Jiao
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Hur
authors.forename: Feng-Quan
authors.initials: FQ
authors.lastname: Zhou
mesh_terms: D000818:Animals; D002460:Cell Line; D059290:Dopaminergic Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism* / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011971:Receptors, Immunologic / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D015398:Signal Transduction; D000098552:Slit Homolog 2 Protein
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic; D011994:Recombinant Proteins; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3; D000098552:Slit Homolog 2 Protein