title: ARF6 regulates neuron differentiation through glucosylceramide synthase.
abstract: The small GTPase ADP ribosylation factor 6 (ARF6) mediates endocytosis and has in addition been shown to regulate neuron differentiation. Here we investigated whether ARF6 promotes differentiation of Neuro-2a neuronal cells by modifying the cellular lipid composition. We showed that knockdown of ARF6 by siRNA in Neuro-2a cells increased neuronal outgrowth as expected. ARF6 knockdown also resulted in increased glucosylceramide levels and decreased sphingomyelin levels, but did not affect the levels of ceramide or phospholipids. We speculated that the ARF6 knockdown-induced increase in glucosylceramide was caused by an effect on glucosylceramide synthase and, in agreement, showed that ARF6 knockdown increased the mRNA levels and activity of glucosylceramide synthase. Finally, we showed that incubation of Neuro-2a cells with the glucosylceramide synthase inhibitor D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) normalized the increased neuronal outgrowth induced by ARF6 knockdown. Our results thus show that ARF6 regulates neuronal differentiation through an effect on glucosylceramide synthase and glucosylceramide levels.
authors.affiliation: Wallenberg Laboratory, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Lu
authors.initials: L
authors.lastname: Li
authors.forename: Marcus
authors.initials: M
authors.lastname: Ståhlman
authors.forename: Mikael
authors.initials: M
authors.lastname: Rutberg
authors.forename: Liliana
authors.initials: L
authors.lastname: Håversen
authors.forename: Per
authors.initials: P
authors.lastname: Fogelstrand
authors.forename: Linda
authors.initials: L
authors.lastname: Andersson
authors.forename: Malin
authors.initials: M
authors.lastname: Levin
authors.forename: Jan
authors.initials: J
authors.lastname: Borén
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D005963:Glucosylceramides / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013109:Sphingomyelins / Q000378:metabolism
chemical_list: D000089982:ADP-Ribosylation Factor 6; D005963:Glucosylceramides; D013109:Sphingomyelins; D005964:Glucosyltransferases; C023246:ceramide glucosyltransferase; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human
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