Lysophosphatidylcholines activate G2A inducing G(αi)₋₁-/G(αq/)₁₁- Ca²(+) flux, G(βγ)-Hck activation and clathrin/β-arrestin-1/GRK6 recruitment in PMNs
| Autor: | Samina Y, Khan, Nathan J D, McLaughlin, Marguerite R, Kelher, Phillip, Eckels, Fabia, Gamboni-Robertson, Anirban, Banerjee, Christopher C, Silliman |
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| Rok vydání: | 2010 |
| Předmět: |
Time Factors
Arrestins Neutrophils Blotting Western Cell Cycle Proteins Article Receptors G-Protein-Coupled Cytosol GTP-Binding Protein gamma Subunits Fluorescence Resonance Energy Transfer Humans Phosphorylation Cells Cultured beta-Arrestins Ion Transport GTP-Binding Protein beta Subunits Lysophosphatidylcholines G-Protein-Coupled Receptor Kinases Heterotrimeric GTP-Binding Proteins Clathrin GTP-Binding Protein alpha Subunits Enzyme Activation beta-Arrestin 1 Microscopy Fluorescence Proto-Oncogene Proteins c-hck lipids (amino acids peptides and proteins) Calcium Protein Kinases Signal Transduction |
| Zdroj: | The Biochemical journal. 432(1) |
| ISSN: | 1470-8728 |
| Popis: | Lyso-PCs (lysophosphatidylcholines) are a mixture of lipids that accumulate during storage of cellular blood components, have been implicated in TRALI (transfusion-related acute lung injury) and directly affect the physiology of neutrophils [PMNs (polymorphonuclear leucocytes)]. Because the G2A receptor, expressed on PMNs, has been reported to recognize lyso-PCs, we hypothesize that lyso-PC activation of G2A causes the increases in cytosolic Ca²(+) via release of G(α) and G(βγ) subunits, kinase activation, and the recruitment of clathrin, β-arrestin-1 and GRK6 (G-protein receptor kinase 6) to G2A for signal transduction. PMNs were isolated by standard techniques, primed with lyso-PCs for 5-180 s, and lysed for Western blot analysis, immunoprecipitation or subcellular fractionation, or fixed and smeared on to slides for digital microscopy. The results demonstrated that lyso-PCs cause rapid activation of the G2A receptor through S-phosphorylation and internalization resulting in G(αi)₋₁ and G(αq/)₁₁ release leading to increases in cytosolic Ca²(+), which was inhibited by an antibody to G2A or intracellular neutralization of these subunits. Lyso-PCs also caused the release of the G(βγ) subunit which demonstrated a physical interaction (FRET+) with activated Hck (haemopoietic cell kinase; Tyr⁴¹¹). Moreover, G2A recruited clathrin, β-arrestin-1 and GRK6: clathrin is important for signal transduction, GRK6 for receptor de-sensitization, and β-arrestin-1 both propagates and terminates signals. We conclude that lyso-PC activation of G2A caused release of G(αi)₋₁, G(αq/)₁₁ and G(βγ), resulting in cytosolic Ca²(+) flux, Hck activation, and recruitment of clathrin, β-arrestin-1 and GRK6. |
| Databáze: | OpenAIRE |
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