title: Insulin increases the functional activity of the renal NaCl cotransporter.
abstract: OBJECTIVE
  Insulin is recognized to increase renal salt reabsorption in the distal nephron and hyperinsulinemic states have been shown to be associated with increased expression of the renal NaCl cotransporter (NCC). However, the effect of insulin on NCC functional activity has not been reported.
  
  
  METHODS
  Using a heterologous expression system of Xenopus laevis oocytes, a mouse distal convoluted cell line, mDCT15 cells, endogenously expressing NCC, and an ex-vivo kidney perfusion technique, we assessed the effect of insulin on the activity and phosphorylation of NCC. The signaling pathway involved was analyzed.
  
  
  RESULTS
  In Xenopus oocytes insulin increases the activity of NCC together with its phosphorylation at threonine residue 58. Activation of NCC by insulin was also observed in mDCT15 cells. Additionally, insulin increased the NCC phosphorylation in kidney under the ex-vivo perfusion technique. In oocytes and mDCT15 cells, insulin effect on NCC was prevented with inhibitors of phosphatidylinositol 3-kinase (PI3K), mTORC2, and AKT1 kinases, but not by inhibitors of MAP or mTORC1 kinases, suggesting that PI3K-mTORC2-AKT1 is the intracellular pathway required. Additionally, activation of NCC by insulin was not affected by wild-type or mutant versions of with no lysine kinase 1, with no lysine kinase 4, or serum glucocorticoid kinase 1, but it was no longer observed in the presence of wild-type or the dominant negative, catalytically inactive with no lysine kinase 3, implicating this kinase in the process.
  
  
  CONCLUSIONS
  Insulin induces activation and phosphorylation of NCC. This effect could play an important role in arterial hypertension associated with hyperinsulinemic states, such as obesity, metabolic syndrome, or type 2 diabetes mellitus.
authors.affiliation: Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico.
authors.forename: María
authors.initials: M
authors.lastname: Chávez-Canales
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Arroyo
authors.forename: Benajmin
authors.initials: B
authors.lastname: Ko
authors.forename: Norma
authors.initials: N
authors.lastname: Vázquez
authors.forename: Rocio
authors.initials: R
authors.lastname: Bautista
authors.forename: María
authors.initials: M
authors.lastname: Castañeda-Bueno
authors.forename: Norma A
authors.initials: NA
authors.lastname: Bobadilla
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hoover
authors.forename: Gerardo
authors.initials: G
authors.lastname: Gamba
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D007328:Insulin / Q000494:pharmacology*; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D000076225:Mechanistic Target of Rapamycin Complex 2; D051379:Mice; D046912:Multiprotein Complexes / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D049992:Sodium Chloride Symporters / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D007328:Insulin; D000076225:Mechanistic Target of Rapamycin Complex 2; D046912:Multiprotein Complexes; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D049992:Sodium Chloride Symporters; D058570:TOR Serine-Threonine Kinases