Agonist-induced internalization and mitogen-activated protein kinase activation of the human prostaglandin EP4 receptor.
We examined the pathway of prostaglandin E(2) (PGE(2))-induced internalization of the prostaglandin EP4 receptor in HEK 293 cells. Co-expression of dominant negative beta-arrestin (319-418) or dynamin I (K44A) with the EP4 receptor reduced internalization. The activated receptor co-localized with GFP-arrestin 2 and GFP-arrestin 3, confirming the requirement for beta-arrestins in internalization. Inhibition of clathrin-coated vesicle-mediated internalization resulted in inhibition of sequestration, whereas inhibition of caveola-mediated internalization had no effect. PGE(2) stimulation of the EP4 receptor resulted in rapid mitogen-activated protein (MAP) kinase activation. Examination of an internalization-resistant mutant and co-expression of mutant accessory proteins with EP4 revealed that MAP kinase activation proceeds independently of internalization.
Desai
S
S
Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
Ashby
B
B
D019342:Acetic Acid / Q000494:pharmacology; D019390:Arrestins / Q000494:pharmacology*; D002478:Cells, Cultured; D034284:Dynamin I; D034281:Dynamins; D004705:Endocytosis / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D020558:GTP Phosphohydrolases / Q000494:pharmacology*; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010750:Phosphoproteins / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D018078:Receptors, Prostaglandin E / Q000819:agonists* / Q000378:metabolism; D058309:Receptors, Prostaglandin E, EP4 Subtype; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000071557:beta-Arrestins
D019390:Arrestins; D008164:Luminescent Proteins; C545650:PTGER4 protein, human; D010750:Phosphoproteins; D018078:Receptors, Prostaglandin E; D058309:Receptors, Prostaglandin E, EP4 Subtype; C082333:arrestin3; D000071557:beta-Arrestins; D049452:Green Fluorescent Proteins; D020928:Mitogen-Activated Protein Kinases; D034284:Dynamin I; D020558:GTP Phosphohydrolases; D034281:Dynamins; D013755:Tetradecanoylphorbol Acetate; D019342:Acetic Acid