title: Mutation of a putative MAP kinase consensus site regulates NCAM endocytosis and NCAM-dependent neurite outgrowth.
abstract: The cytoplasmic domain of the neural cell adhesion molecule NCAM contains several putative serine/threonine phosphorylation sites whose functions are largely unknown. Human NCAM140 (NCAM140) possesses a potential MAP kinase phosphorylation site at threonine (T) 803. The aim of this study was to analyze a possible phosphorylation of NCAM140 by MAP kinases and to identify the functional role of T803. We found that NCAM140 is phosphorylated by the MAP kinase ERK2 in vitro. Exchange of T803 to aspartic acid (D) which mimics constitutive phosphorylation at the respective position resulted in increased endocytosis compared to NCAM140 in neuroblastoma cells and primary neurons. Consistently, NCAM140 endocytosis was inhibited by the MEK inhibitor U0126 in contrast to NCAM140-T803D or NCAM140-T803A endocytosis supporting a role of a potential ERK2 mediated phosphorylation at this site in endocytosis. Furthermore, cells expressing NCAM140-T803D developed significantly shorter neurites than NCAM140 expressing cells indicating that a potential phosphorylation of NCAM by ERK2 also regulates NCAM-dependent neurite outgrowth.
authors.affiliation: Institute of Nutrition and Food Sciences, Human Metabolomics, University of Bonn, Katzenburgweg 9a, 53115 Bonn, Germany. Electronic address: tobiasgoschzik@web.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Goschzik
authors.affiliation: IBDM-Developmental Biology Institute of Marseille, UMR 7288, Case 907-Parc Scientifique de Luminy, 13288 Marseille Cedex 9, France. Electronic address: harold.cremer@univ-amu.fr.
authors.forename: Harold
authors.initials: H
authors.lastname: Cremer
authors.affiliation: Institute for Physiological Chemistry, Martin-Luther-University, Halle-Wittenberg, Hollystr. 1, 06114 Halle, Saale, Germany. Electronic address: vinayaga.gnanapragassam@medizin.uni-halle.de.
authors.forename: Vinayaga S
authors.initials: VS
authors.lastname: Gnanapragassam
authors.affiliation: Institute for Physiological Chemistry, Martin-Luther-University, Halle-Wittenberg, Hollystr. 1, 06114 Halle, Saale, Germany. Electronic address: ruediger.horstkorte@medizin.uni-halle.de.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Horstkorte
authors.affiliation: Institute for Physiological Chemistry, Martin-Luther-University, Halle-Wittenberg, Hollystr. 1, 06114 Halle, Saale, Germany. Electronic address: kaya.bork@medizin.uni-halle.de.
authors.forename: Kaya
authors.initials: K
authors.lastname: Bork
authors.affiliation: Institute of Nutrition and Food Sciences, Human Metabolomics, University of Bonn, Katzenburgweg 9a, 53115 Bonn, Germany. Electronic address: s.diestel@uni-bonn.de.
authors.forename: Simone
authors.initials: S
authors.lastname: Diestel
mesh_terms: D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D002478:Cells, Cultured; D004705:Endocytosis; D006801:Humans; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D009154:Mutation; D000071446:Neuronal Outgrowth; D010766:Phosphorylation
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; C520249:NCAM140, human; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1
keywords: ERK phosphorylation; Endocytosis; Human NCAM140; Neurite outgrowth