Homocysteine effects classical pathway of GPCR down regulation: Galpha(q/11), Galpha(12/13), G(i/o)
| Autor: | T P, Vacek, U, Sen, N, Tyagi, M, Kumar, K S, Moshal, J C, Passmore, S C, Tyagi |
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| Rok vydání: | 2008 |
| Předmět: |
Dose-Response Relationship
Drug G-Protein-Coupled Receptor Kinase 2 Down-Regulation Endothelial Cells GTP-Binding Protein alpha Subunits Gi-Go GTP-Binding Protein alpha Subunits G12-G13 Article Rats Receptors G-Protein-Coupled Animals GTP-Binding Protein alpha Subunits Gq-G11 Extracellular Signal-Regulated MAP Kinases Homocysteine Cells Cultured Signal Transduction |
| Zdroj: | Molecular and cellular biochemistry. 321(1-2) |
| ISSN: | 1573-4919 |
| Popis: | G protein-coupled receptors (GPCRs) are known to modulate intracellular effectors involved in cardiac function. We recently reported homocysteine (Hcy)-induced ERK-phosphorylation was suppressed by pertussis toxin (PTX), which suggested the involvement of GPCRs in initiating signal transduction. An activated GPCR undergoes down regulation via a known mechanism involving ERK, GRK2, beta-arrestin1: ERK activity increases; GRK2 activity increases; beta-arrestin1 is degraded. We hypothesized that Hcy treatment leads to GPCR activation and down regulation. Microvascular endothelial cells were treated with Hcy. Expression of phospho-ERK1 and phospho-GRK2 was determined using Western blot, standardized to ERK1, GRK2, and beta-actin. Hcy was shown to dephosphorylate GRK2, thereby enhancing the activity. The results provided further evidence that Hcy acts as an agonist to activate GPCRs, followed by their down regulation. Hcy was also shown to decrease the content of the following G proteins and other proteins: beta-arrestin1, Galpha(q/11), Galpha(12/13), G(i/o). |
| Databáze: | OpenAIRE |
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