title: Conventional protein kinase C isoforms mediate phorbol ester-induced lysophosphatidic acid LPA1 receptor phosphorylation.
abstract: Using C9 cells stably expressing LPA1 receptors fused to the enhanced green fluorescent protein, it was observed that activation of protein kinase C induced a rapid and strong increase in the phosphorylation state of these receptors. Overnight incubation with phorbol esters markedly decreased the amount of conventional (α, βI, βII and γ) and novel (δ) but not atypical (ζ) immunodetected PKC isoforms, this treatment blocks the action of protein kinase on receptor function and phosphorylation. Bis-indolylmaleimide I a general, non-subtype selective protein kinase C inhibitor, and Gö 6976, selective for the isoforms α and β, were also able to block LPA1 receptor desensitization and phosphorylation; hispidin, isoform β-selective blocker partially avoided receptor desensitization. Expression of dominant-negative protein kinase C α or β II mutants and knocking down the expression of these kinase isozymes markedly decreased phorbol ester-induced LPA1 receptor phosphorylation without avoiding receptor desensitization. This effect was blocked by bis-indolyl-maleimide and Gö 6976, suggesting that these genetic interventions were not completely effective. It was also observed that protein kinase C α and β II isozymes co-immunoprecipitate with LPA1 receptors and that such an association was further increased by cell treatments with phorbol esters or lysophosphatidic acid. Our data suggest that conventional protein kinase C α and β isozymes modulate LPA1 receptor phosphorylation state. Receptor desensitization appears to be a more complex process that might involve additional elements.
authors.affiliation: Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México D. F-04510, Mexico.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Hernández-Méndez
authors.affiliation: Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México D. F-04510, Mexico.
authors.forename: Rocío
authors.initials: R
authors.lastname: Alcántara-Hernández
authors.affiliation: Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México D. F-04510, Mexico.
authors.forename: Germán C
authors.initials: GC
authors.lastname: Acosta-Cervantes
authors.affiliation: Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México D. F-04510, Mexico.
authors.forename: Javier
authors.initials: J
authors.lastname: Martínez-Ortiz
authors.affiliation: Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México D. F-04510, Mexico.
authors.forename: S Eréndira
authors.initials: SE
authors.lastname: Avendaño-Vázquez
authors.affiliation: Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México D. F-04510, Mexico. Electronic address: agarcia@ifc.unam.mx.
authors.forename: J Adolfo
authors.initials: JA
authors.lastname: García-Sáinz
mesh_terms: D000818:Animals; D002460:Cell Line; D007527:Isoenzymes / Q000378:metabolism; D008246:Lysophospholipids / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D049368:Receptors, Lysophosphatidic Acid / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D007527:Isoenzymes; D008246:Lysophospholipids; D049368:Receptors, Lysophosphatidic Acid; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; C032881:lysophosphatidic acid
keywords: LPA(1); Lysophosphatidic acid; Protein kinase C; Receptor phosphorylation