title: The Coffin-Lowry syndrome-associated protein RSK2 regulates neurite outgrowth through phosphorylation of phospholipase D1 (PLD1) and synthesis of phosphatidic acid.
abstract: More than 80 human X-linked genes have been associated with mental retardation and deficits in learning and memory. However, most of the identified mutations induce limited morphological alterations in brain organization and the molecular bases underlying neuronal clinical features remain elusive. We show here that neurons cultured from mice lacking ribosomal S6 kinase 2 (Rsk2), a model for the Coffin-Lowry syndrome (CLS), exhibit a significant delay in growth in a similar way to that shown by neurons cultured from phospholipase D1 (Pld1) knock-out mice. We found that gene silencing of Pld1 or Rsk2 as well as acute pharmacological inhibition of PLD1 or RSK2 in PC12 cells strongly impaired neuronal growth factor (NGF)-induced neurite outgrowth. Expression of a phosphomimetic PLD1 mutant rescued the inhibition of neurite outgrowth in PC12 cells silenced for RSK2, revealing that PLD1 is a major target for RSK2 in neurite formation. NGF-triggered RSK2-dependent phosphorylation of PLD1 led to its activation and the synthesis of phosphatidic acid at sites of neurite growth. Additionally, total internal reflection fluorescence microscopy experiments revealed that RSK2 and PLD1 positively control fusion of tetanus neurotoxin insensitive vesicle-associated membrane protein (TiVAMP)/VAMP-7 vesicles at sites of neurite outgrowth. We propose that the loss of function mutations in RSK2 that leads to CLS and neuronal deficits are related to defects in neuronal growth due to impaired RSK2-dependent PLD1 activity resulting in a reduced vesicle fusion rate and membrane supply.
authors: Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique UPR-3212, Université de Strasbourg, 67084 Strasbourg, France, Institut Interdisciplinaire de Neuroscience, Centre National de la Recherche Scientifique UMR-5297, Université de Bordeaux, 33077 Bordeaux Cedex, France, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, UMR-7104/U964 Université de Strasbourg, 67404 Illkirch Cedex, France, and University Hospital and Rudolf Virchow Center, Deutsche Forschungsgemeinschaft Research Center for Experimental Biomedicine, 97080 Würzburg, Germany.
authors: Mohamed-Raafet
authors: MR
authors: Ammar
authors: Yann
authors: Y
authors: Humeau
authors: André
authors: A
authors: Hanauer
authors: Bernard
authors: B
authors: Nieswandt
authors: Marie-France
authors: MF
authors: Bader
authors: Nicolas
authors: N
authors: Vitale
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D038921:Coffin-Lowry Syndrome / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D020932:Nerve Growth Factor / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D016716:PC12 Cells; D010712:Phosphatidic Acids / Q000096:biosynthesis*; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000235:genetics / Q000378:metabolism*
chemical_list: D010712:Phosphatidic Acids; D020932:Nerve Growth Factor; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C069330:ribosomal protein S6 kinase, 90kDa, polypeptide 3; D010739:Phospholipase D; C106801:phospholipase D1