title: Metabotropic glutamate type 1alpha receptor localizes in low-density caveolin-rich plasma membrane fractions.
abstract: Recent evidence suggest that many G protein-coupled receptors (GPCR) and signalling molecules localize in microdomains of the plasma membrane. In this study, flotation gradient analysis in the absence of detergents demonstrated the presence of the metabotropic glutamate receptor type 1alpha (mGlu1alpha) in low-density caveolin-enriched membrane fractions (CEMF) in permanently transfected BHK cells. BHK-1alpha cells exhibit a similar pattern of staining for caveolin-1 and caveolin-2, and these two proteins show a high degree of co-localization with mGlu1alpha receptor as demonstrated by immunogold and confocal laser microscopy. The presence of mGlu1alpha in CEMF was also demonstrated by co-immunoprecipitation of mGlu1alpha receptor using antibodies against caveolin proteins. Activation of the mGlu1alpha receptor by agonist increased extracellular signal-regulated kinases phosphorylation in CEMF and not in high-density membrane fractions (HDMF), suggesting that mGlu1alpha receptor-mediated signal transduction could occur in caveolae-like domains. Overall, these results clearly show a molecular and functional association of mGlu1alpha receptor with caveolins.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Química, IDIBAPS, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Burgueño
authors.forename: Carlos
authors.initials: C
authors.lastname: Enrich
authors.forename: Enric I
authors.initials: EI
authors.lastname: Canela
authors.forename: Josefa
authors.initials: J
authors.lastname: Mallol
authors.forename: Carmen
authors.initials: C
authors.lastname: Lluis
authors.forename: Rafael
authors.initials: R
authors.lastname: Franco
authors.forename: Francisco
authors.initials: F
authors.lastname: Ciruela
mesh_terms: D000818:Animals; D051242:Caveolin 1; D051243:Caveolin 2; D022461:Caveolins / Q000032:analysis / Q000096:biosynthesis*; D002458:Cell Fractionation; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D006224:Cricetinae; D007150:Immunohistochemistry; D007668:Kidney / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D018094:Receptors, Metabotropic Glutamate / Q000032:analysis / Q000096:biosynthesis*; D013347:Subcellular Fractions / Q000737:chemistry
chemical_list: D051242:Caveolin 1; D051243:Caveolin 2; D022461:Caveolins; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1