Lysophosphatidylcholines activate G2A inducing G(αi)â1-/G(αq/)11- Ca²(+) flux, G(ßγ)-Hck activation and clathrin/ß-arrestin-1/GRK6 recruitment in PMNs.
Biochem J
; 432(1): 35-45, 2010 Nov 15.
Article
em En
| MEDLINE
| ID: mdl-20799926
ABSTRACT
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(ßγ) subunits, kinase activation, and the recruitment of clathrin, ß-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)â1 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(ßγ) subunit which demonstrated a physical interaction (FRET+) with activated Hck (haemopoietic cell kinase; Tyr4¹¹). Moreover, G2A recruited clathrin, ß-arrestin-1 and GRK6 clathrin is important for signal transduction, GRK6 for receptor de-sensitization, and ß-arrestin-1 both propagates and terminates signals. We conclude that lyso-PC activation of G2A caused release of G(αi)â1, G(αq/)11 and G(ßγ), resulting in cytosolic Ca²(+) flux, Hck activation, and recruitment of clathrin, ß-arrestin-1 and GRK6.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Quinases
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Lisofosfatidilcolinas
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Cálcio
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Proteínas de Ciclo Celular
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Proteínas Heterotriméricas de Ligação ao GTP
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Receptores Acoplados a Proteínas G
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Neutrófilos
Limite:
Humans
Idioma:
En
Revista:
Biochem J
Ano de publicação:
2010
Tipo de documento:
Article