Defective processing and expression of thiazide-sensitive Na-Cl cotransporter as a cause of Gitelman's syndrome

Shanti Kunchaparty, Matthew Palcso, Jennifer Berkman, Heino Velázquez, Gary V. Desir, Paul Bernstein, Robert F. Reilly, David Ellison

Research output: Contribution to journalArticle

120 Citations (Scopus)

Abstract

Gitelman's syndrome is an autosomal recessive disorder of salt wasting and hypokalemia caused by mutations in the thiazide-sensitive Na-Cl cotransporter. To investigate the pathogenesis of Gitelman's syndrome, eight disease mutations were introduced into the mouse thiazide-sensitive Na-Cl cotransporter and studied by functional expression in Xenopus oocytes. Sodium uptake into oocytes that expressed the wild-type clone was more than sevenfold greater than uptake into control oocytes. Uptake into oocytes that expressed the mutated transporters was not different from control. Hydrochlorothiazide reduced Na uptake by oocytes expressing the wild-type gene to control values but had no effect on oocytes expressing the mutant clones. Western blots of oocytes injected with the wild-type clone showed bands representing glycosylated (125 kDa) and unglycosylated (110 kDa) forms of the transport protein. Immunoblot of oocytes expressing the mutated clones showed only the unglycosylated protein, indicating that protein processing was disrupted. Immunocytochemistry with an antibody against the transport protein showed intense membrane staining of oocytes expressing the wild-type protein. Membrane staining was completely absent from oocytes expressing mNCC(R948x); instead, diffuse cytoplasmic staining was evident. In summary, the results show that several mutations that cause Gitelman's syndrome are nonfunctional because the mutant thiazide-sensitive Na-Cl cotransporter is not processed normally, probably activating the 'quality control' mechanism of the endoplasmic reticulum.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Physiology
Volume277
Issue number4 46-4
StatePublished - Oct 1999
Externally publishedYes

Fingerprint

Gitelman Syndrome
Oocytes
Clone Cells
Staining and Labeling
Mutation
Carrier Proteins
thiazide receptor
Proteins
Hydrochlorothiazide
Membranes
Hypokalemia
Xenopus
Endoplasmic Reticulum
Quality Control

Keywords

  • Blood pressure
  • Distal
  • Distal convoluted tubule
  • Diuretics
  • Familial hypokalemia-hypomagnesemia
  • Kidney tubules
  • Thiazide
  • Thiazide- sensitive sodium-chloride cotransporter

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Defective processing and expression of thiazide-sensitive Na-Cl cotransporter as a cause of Gitelman's syndrome. / Kunchaparty, Shanti; Palcso, Matthew; Berkman, Jennifer; Velázquez, Heino; Desir, Gary V.; Bernstein, Paul; Reilly, Robert F.; Ellison, David.

In: American Journal of Physiology - Renal Physiology, Vol. 277, No. 4 46-4, 10.1999.

Research output: Contribution to journalArticle

Kunchaparty, S, Palcso, M, Berkman, J, Velázquez, H, Desir, GV, Bernstein, P, Reilly, RF & Ellison, D 1999, 'Defective processing and expression of thiazide-sensitive Na-Cl cotransporter as a cause of Gitelman's syndrome', American Journal of Physiology - Renal Physiology, vol. 277, no. 4 46-4.
Kunchaparty, Shanti ; Palcso, Matthew ; Berkman, Jennifer ; Velázquez, Heino ; Desir, Gary V. ; Bernstein, Paul ; Reilly, Robert F. ; Ellison, David. / Defective processing and expression of thiazide-sensitive Na-Cl cotransporter as a cause of Gitelman's syndrome. In: American Journal of Physiology - Renal Physiology. 1999 ; Vol. 277, No. 4 46-4.
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