γ-Adducin stimulates the thiazide-sensitive NaCl cotransporter

J Am Soc Nephrol. 2011 Mar;22(3):508-17. doi: 10.1681/ASN.2010060606. Epub 2010 Dec 16.

Abstract

The thiazide-sensitive NaCl cotransporter (NCC) plays a key role in renal salt reabsorption and the determination of systemic BP, but the molecular mechanisms governing the regulation of NCC are not completely understood. Here, through pull-down experiments coupled to mass spectrometry, we found that γ-adducin interacts with the NCC transporter. γ-Adducin colocalized with NCC to the distal convoluted tubule. (22)Na(+) uptake experiments in the Xenopus laevis oocyte showed that γ-adducin stimulated NCC activity in a dose-dependent manner, an effect that occurred upstream from With No Lysine (WNK) 4 kinase. The binding site of γ-adducin mapped to the N terminus of NCC and encompassed three previously reported phosphorylation sites. Supporting this site of interaction, competition with the N-terminal domain of NCC abolished the stimulatory effect of γ-adducin on the transporter. γ-Adducin failed to increase NCC activity when these phosphorylation sites were constitutively inactive or active. In addition, γ-adducin bound only to the dephosphorylated N terminus of NCC. Taken together, our observations suggest that γ-adducin dynamically regulates NCC, likely by amending the phosphorylation state, and consequently the activity, of the transporter. These data suggest that γ-adducin may influence BP homeostasis by modulating renal NaCl transport.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption / physiology
  • Animals
  • Blood Pressure / physiology*
  • Calmodulin-Binding Proteins / metabolism*
  • Calmodulin-Binding Proteins / pharmacology
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Kidney Tubules, Distal / cytology
  • Kidney Tubules, Distal / metabolism*
  • Models, Animal
  • Oocytes / cytology
  • Oocytes / drug effects
  • Oocytes / metabolism
  • Phosphorylation
  • Sodium Chloride / metabolism
  • Sodium Chloride Symporters / metabolism*
  • Xenopus laevis

Substances

  • Calmodulin-Binding Proteins
  • Sodium Chloride Symporters
  • adducin
  • Sodium Chloride