Astrocytes express Mxi2, a splice isoform of p38MAPK.
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.
Bodega
Guillermo
G
Departamento de Biología Celular y Genética, Facultad de Biología, Universidad de Alcalá, Alcalá de Henares, 28871 Madrid, Spain. guillermo.bodega@uah.es
Ciordia
Sergio
S
Suárez
Isabel
I
López-Fernández
Luis Andrés
LA
Vacas
Enrique
E
Sánchez-Tejeda
Gonzalo
G
Albert
María Amparo
MA
Juárez
Silvia
S
Albar
Juan Pablo
JP
Fernández
Benjamín
B
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
D020033:Protein Isoforms; D019950:Mitogen-Activated Protein Kinase 1; D048308:Mitogen-Activated Protein Kinase 14; D048052:Mitogen-Activated Protein Kinase 3