beta1-Adrenergic Receptor Signaling Activates the Epithelial Calcium Channel, Transient Receptor Potential Vanilloid Type 5 (TRPV5), via the Protein Kinase A Pathway.
SourceJournal of Biological Chemistry, 289, 26, (2014), pp. 18489-18496
Article / Letter to editor
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Journal of Biological Chemistry
SubjectRadboudumc 11: Renal disorders RIMLS: Radboud Institute for Molecular Life Sciences
Epinephrine and norepinephrine are present in the pro-urine. beta-Adrenergic receptor (beta-AR) blockers administered to counteract sympathetic overstimulation in patients with congestive heart failure have a negative inotropic effect, resulting in reduced cardiac contractility. Positive inotropes, beta1-AR agonists, are used to improve cardiac functions. Active Ca2+ reabsorption in the late distal convoluted and connecting tubules (DCT2/CNT) is initiated by Ca2+ influx through the transient receptor potential vanilloid type 5 (TRPV5) Ca2+ channel. Although it was reported that beta-ARs are present in the DCT2/CNT region, their role in active Ca2+ reabsorption remains elusive. Here we revealed that beta1-AR, but not beta2-AR, is localized with TRPV5 in DCT2/CNT. Subsequently, treatment of TRPV5-expressing mouse DCT2/CNT primary cell cultures with the beta1-AR agonist dobutamine showed enhanced apical-to-basolateral transepithelial Ca2+ transport. In human embryonic kidney (HEK293) cells, dobutamine was shown to stimulate cAMP production, signifying functional beta1-AR expression. Fura-2 experiments demonstrated increased activity of TRPV5 in response to dobutamine, which could be prevented by the PKA inhibitor H89. Moreover, nonphosphorylable T709A-TRPV5 and phosphorylation-mimicking T709D-TRPV5 mutants were unresponsive to dobutamine. Surface biotinylation showed that dobutamine did not affect plasma membrane abundance of TRPV5. In conclusion, activation of beta1-AR stimulates active Ca2+ reabsorption in DCT2/CNT; an increase in TRPV5 activity via PKA phosphorylation of residue Thr-709 possibly plays an important role. These data explicate a calciotropic role in addition to the inotropic property of beta1-AR.
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