title: γ-Adducin stimulates the thiazide-sensitive NaCl cotransporter.
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.
authors.affiliation: Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Henrik
authors.initials: H
authors.lastname: Dimke
authors.forename: Pedro
authors.initials: P
authors.lastname: San-Cristobal
authors.forename: Mark
authors.initials: M
authors.lastname: de Graaf
authors.forename: Jacques W
authors.initials: JW
authors.lastname: Lenders
authors.forename: Jaap
authors.initials: J
authors.lastname: Deinum
authors.forename: Joost G J
authors.initials: JG
authors.lastname: Hoenderop
authors.forename: René J M
authors.initials: RJ
authors.lastname: Bindels
mesh_terms: D000042:Absorption / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007686:Kidney Tubules, Distal / Q000166:cytology / Q000378:metabolism*; D023421:Models, Animal; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D012965:Sodium Chloride / Q000378:metabolism; D049992:Sodium Chloride Symporters / Q000378:metabolism*; D014982:Xenopus laevis; D000099291:Adducins
chemical_list: D002148:Calmodulin-Binding Proteins; D012965:Sodium Chloride; D049992:Sodium Chloride Symporters; D000099291:Adducins