title: Astrocytes express Mxi2, a splice isoform of p38MAPK.
abstract: Mitogen-activated protein kinases (MAPKs) are a superfamily of cytoplasmic serine/threonine kinases that transduce many types of extracellular stimuli into cellular responses. p38MAPK is a member of this family with its active form in a diphosphorylated state (p38MAPKdiP). Two strong anti-p38MAPKdiP immunoreactive bands (apparent molecular weight 38 and 34 kDa) were detected by Western blotting in cultured astrocytes. Using a specific antibody and employing immunoprecipitation procedures and SELDI-TOF analysis, the 34 kDa band was found to correspond to Mxi2, a splice variant of p38MAPK; cultured astrocytes therefore express Mxi2. Separate protein extractions of different subcellular fractions, and fluorescent immunovisualisation employing confocal microscopy, showed Mxi2 to have a non-nuclear, cytosolic distribution in the studied cells. ERK1/2, protein whose intracellular distribution is influenced by Mxi2, showed the same cytoplasmic pattern than Mxi2.
authors.affiliation: Departamento de Biología Celular y Genética, Facultad de Biología, Universidad de Alcalá, Alcalá de Henares, 28871 Madrid, Spain. guillermo.bodega@uah.es
authors.forename: Guillermo
authors.initials: G
authors.lastname: Bodega
authors.forename: Sergio
authors.initials: S
authors.lastname: Ciordia
authors.forename: Isabel
authors.initials: I
authors.lastname: Suárez
authors.forename: Luis Andrés
authors.initials: LA
authors.lastname: López-Fernández
authors.forename: Enrique
authors.initials: E
authors.lastname: Vacas
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Sánchez-Tejeda
authors.forename: María Amparo
authors.initials: MA
authors.lastname: Albert
authors.forename: Silvia
authors.initials: S
authors.lastname: Juárez
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Albar
authors.forename: Benjamín
authors.initials: B
authors.lastname: Fernández
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001253:Astrocytes / Q000201:enzymology*; D015153:Blotting, Western; D047468:Immunoprecipitation; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048308:Mitogen-Activated Protein Kinase 14 / Q000737:chemistry / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D021381:Protein Transport; D051381:Rats; D017208:Rats, Wistar; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D020033:Protein Isoforms; D019950:Mitogen-Activated Protein Kinase 1; D048308:Mitogen-Activated Protein Kinase 14; D048052:Mitogen-Activated Protein Kinase 3