| Autor: |
Kathleen M. Metters, Natalie Brewer, Deborah Slipetz, Stephanie Buchanan, Cameron D. Mackereth, Vanessa Pellow, Mark Abramovitz, Chuan-ming Hao, Mohammed Adam |
| Rok vydání: |
2001 |
| Předmět: |
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| Zdroj: |
Biochemical Pharmacology. 62:997-1012 |
| ISSN: |
0006-2952 |
| DOI: |
10.1016/s0006-2952(01)00742-0 |
| Popis: |
The prostaglandin E 2 (PGE 2 ) EP 4 subtype is one of four prostanoid receptors that use PGE 2 as the preferred ligand. We have investigated the agonist-mediated regulation of EP 4 using a multifaceted approach. Short-term (30 min) agonist challenge of recombinant EP 4 expressed in human embryonic kidney 293 cells (EP 4 -HEK293 cells) with PGE 2 (1 μM) resulted in the desensitization of intracellular cyclic AMP (cAMP) accumulation and a reduction in cell surface [ 3 H]PGE 2 specific binding sites. These events correlated with sequestration of EP 4 , as visualized by immunofluorescence confocal microscopy and phosphorylation, as shown by [ 32 P]orthophosphate labeling of the receptor. Stimulation of protein kinase A activity in EP 4 -HEK293 cells (10 μM forskolin or 1 mM 8-bromo-cAMP) did not induce EP 4 desensitization, sequestration, or phosphorylation. In contrast, stimulation of protein kinase C activity (100 nM phorbol 12-myristate 13-acetate) attenuated PGE 2 -induced adenylyl cyclase activity and increased EP 4 phosphorylation, but did not induce sequestration or a reduction in [ 3 H]PGE 2 specific binding sites. EP 4 receptors containing a third intracellular loop deletion [EP 4 (del. 215–263)] or a carboxyl-terminal tail truncation [EP 4 (del. 355)] of EP 4 were used to demonstrate that the C-terminal tail governs sequestration as well as phosphorylation of the receptor. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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