Human kidney-2 cells harbor functional dopamine D1 receptors that require Giα for Gq/11α signaling.
Am J Physiol Renal Physiol
; 305(4): F560-7, 2013 Aug 15.
Article
en En
| MEDLINE
| ID: mdl-23698121
A recent study demonstrated that the dopamine D1 receptor (D1R) is nonfunctional in human kidney cells, HK2 cells, in terms of their inability to couple to Gs protein in response to the D1R agonist fenoldopam. Since D1R also couples to Gq protein, we tested whether D1R is functional in HK2 cells in terms of their ability to couple to Gq and produce downstream signaling. For comparison, we also studied another receptor, angiotensin II type 1 receptor (AT1R) known to couple to Gq. Protein kinase C (PKC) and (86)rubidium transport activities were determined as surrogate downstream signaling markers. Fenoldopam and angiotensin II increased PKC activity, which decreased in the presence of respective receptor antagonists (SCH23390 for D1R; candesartan for AT1R), PKC (chelerythrine chloride) and Gi protein (pertussis toxin) inhibitors and Gq/11α siRNA. Furthermore, fenoldopam and angiotensin II increased (35)S-GTPγS binding, an index of receptor-G protein coupling, which decreased with pertussis toxin and in Gq/11α-depleted cells. Also, fenoldopam-mediated inhibition of (86)rubidium transport (an index of Na-K-ATPase activity) was attenuated with SCH23390, chelerythrine chloride, pertussis toxin, and Gq/11α siRNA. Moreover, fenoldopam caused a decrease in cytosolic and increase in membranous abundance of Gq/11α. The immunoprecipitated levels of Gq/11α in the membranes were greater in fenoldopam-treated cells, and Giα coimmunoprecipitated with Gq/11α. Our results suggest that both D1R and AT1R are functional in HK2 cells, enabling Gq-mediated downstream signaling in a Gi dependent manner.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptores de Dopamina D1
/
Subunidades alfa de la Proteína de Unión al GTP Gi-Go
/
Subunidades alfa de la Proteína de Unión al GTP Gq-G11
/
Riñón
/
Túbulos Renales Proximales
Límite:
Humans
Idioma:
En
Revista:
Am J Physiol Renal Physiol
Asunto de la revista:
FISIOLOGIA
/
NEFROLOGIA
Año:
2013
Tipo del documento:
Article
Pais de publicación:
Estados Unidos