Na+-Ca2+ exchanger of rat proximal tubule: Gene expression and subcellular localization

Jesus Dominguez, Magdalena Juhaszova, Steven B. Kleiboeker, Calvin C. Hale, Hilary A. Feister

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The activity of the Na+-Ca2+ exchanger, a membrane transporter that mediates Ca2+ efflux, has been described in amphibian and mammalian renal proximal tubules. However, demonstration of cell-specific expression of the Na+-Ca2+ exchanger in proximal renal tubules has been restricted to functional assays. In this work, Na+-Ca2+ exchanger gene expression in rat proximal tubules was characterized by three additional criteria: functional assay of transport activity in membrane vesicles derived from proximal tubules, expression of specific Na+-Ca2+ exchanger protein detected on Western blots, and determination of specific mRNA encoding Na+-Ca2+ exchanger protein on Northern blots. A new transport activity assay showed that proximal tubule membranes contained the highest Na+-Ca2+ exchanger transport activity reported in renal tissues. In dog renal proximal tubules and sarcolemma, a specific protein of ∼70 kDa was detected, whereas in rat proximal tubules and sarcolemma, the specific protein approximated 65 kDa and was localized to the basolateral membrane. On Northern blots, a single 7-kb transcript isolated from rat proximal tubules, whole kidney, and heart hybridized under high-stringency conditions with rat heart cDNA. These data indicate that Na+-Ca2+ exchanger protein expressed in rat proximal tubule is similar, if not identical, to the cardiac protein. We suggest that the tubular Na+-Ca2+ exchanger characterized herein represents the Na+-Ca2+ exchanger described in functional assays of renal proximal tubules.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume263
Issue number5 32-5
StatePublished - Nov 1992

Fingerprint

Proximal Kidney Tubule
Gene Expression
Sarcolemma
Proteins
Northern Blotting
Membranes
Membrane Transport Proteins
Amphibians
Complementary DNA
Western Blotting
Dogs
Kidney
Messenger RNA

Keywords

  • Calcium efflux
  • Sodium-calcium exchanger

ASJC Scopus subject areas

  • Physiology
  • Medicine(all)

Cite this

Na+-Ca2+ exchanger of rat proximal tubule : Gene expression and subcellular localization. / Dominguez, Jesus; Juhaszova, Magdalena; Kleiboeker, Steven B.; Hale, Calvin C.; Feister, Hilary A.

In: American Journal of Physiology - Renal Fluid and Electrolyte Physiology, Vol. 263, No. 5 32-5, 11.1992.

Research output: Contribution to journalArticle

Dominguez, Jesus ; Juhaszova, Magdalena ; Kleiboeker, Steven B. ; Hale, Calvin C. ; Feister, Hilary A. / Na+-Ca2+ exchanger of rat proximal tubule : Gene expression and subcellular localization. In: American Journal of Physiology - Renal Fluid and Electrolyte Physiology. 1992 ; Vol. 263, No. 5 32-5.
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