title: Binding of alphaII spectrin to 14-3-3beta is involved in NCAM-dependent neurite outgrowth.
abstract: Members of the 14-3-3 protein family have been implicated in neuronal migration, synaptic plasticity and learning. Using affinity chromatography followed by mass spectrometry analysis, we show here that the cytoskeletal protein alphaII spectrin is a novel ligand of 14-3-3beta. We found that 14-3-3beta interacts with alphaII spectrin via the mode 2 14-3-3 binding motif RLIQS(1302)HP. Binding required phosphorylation of Ser(1302) by casein kinase II and was enhanced in the presence of calmodulin. Co-immunoprecipitation of alphaII spectrin and 14-3-3beta with the neural cell adhesion molecule NCAM suggested that the 14-3-3-spectrin-interaction affects NCAM function. Indeed, disruption of the 14-3-3beta/alphaII spectrin interaction by mutating Ser(1302) to Ala enhanced NCAM-dependent neurite outgrowth. Our results indicate that the phosphorylation-dependent interaction between 14-3-3beta and alphaII spectrin acts as a switch between positive and negative regulation of neurite outgrowth stimulated by NCAM, representing a novel and acute mechanism preventing uncontrolled elongation of neuronal processes.
authors.affiliation: Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany.
authors.forename: Elisa M
authors.initials: EM
authors.lastname: Ramser
authors.forename: Friedrich
authors.initials: F
authors.lastname: Buck
authors.forename: Melitta
authors.initials: M
authors.lastname: Schachner
authors.forename: Thomas
authors.initials: T
authors.lastname: Tilling
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism; D047390:Casein Kinase II / Q000378:metabolism; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013049:Spectrin / Q000235:genetics / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D002147:Calmodulin; D019006:Neural Cell Adhesion Molecules; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D013049:Spectrin; D047390:Casein Kinase II