Isolation of putative voltage-gated epithelial K-channel isoforms from rabbit kidney and LLC-PKi cells

Gary V. Desir, Henry A. Hamlin, Elaine Puente, Robert F. Reilly, Friedhelm Hildebrandt, Peter Igarashi

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Epithelial voltage-gated potassium (K) channels have been well studied using electrophysiological methods, but little is known about their structures. We tested the hypothesis that some of these channels belong to the Shaker gene family, which encodes voltage-gated K channels in excitable tissues. From published sequences of Shaker proteins in Drosophila, rat, and mouse brain, we chose regions that were conserved between species. Based on these protein sequences, degenerate oligonucleotides flanking the putative voltage sensor (S4) were synthesized and used as primers for the polymerase chain reaction. Five Shaker-like cDNAs were amplified from rabbit kidney cortex and three from LLC-PK1, an epithelial cell line derived from pig kidney. Each partial-length rabbit kidney cDNA is ∼850 base pairs (bp) long. The deduced amino acid sequences contain five putative transmembrane segments and are 79-97% identical to two Shaker isoforms expressed in rat brain (RBK1 and RBK2). Sequence similarity is greatest in the putative transmembrane segments S1-S5. Importantly, the S4 segment, the putative voltage gate is highly conserved in all 5 cDNAs. Southern analysis of rabbit genomic DNA suggests that each isoform is encoded by a different gene. The partial length LLC-PKi cDNAs are 450-bp long, and the deduced amino acid sequences are 77-99% identical to the rabbit cDNAs. This is, to our knowledge, the first demonstration that Shaker-like genes are expressed in renal epithelial cells. These genes most likely encode voltage-gated K channels involved in renal epithelial K transport.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume262
Issue number1
StatePublished - 1992

Fingerprint

Voltage-Gated Potassium Channels
Protein Isoforms
Complementary DNA
Rabbits
Kidney
Base Pairing
Genes
Amino Acid Sequence
Epithelial Cells
LLC-PK1 Cells
Kidney Cortex
Brain
Oligonucleotides
Swine
Cell Line
Polymerase Chain Reaction
DNA
Proteins

Keywords

  • Conductance
  • Gene expression
  • Kidney epithelia
  • Potassium channel

ASJC Scopus subject areas

  • Physiology

Cite this

Isolation of putative voltage-gated epithelial K-channel isoforms from rabbit kidney and LLC-PKi cells. / Desir, Gary V.; Hamlin, Henry A.; Puente, Elaine; Reilly, Robert F.; Hildebrandt, Friedhelm; Igarashi, Peter.

In: American Journal of Physiology - Renal Fluid and Electrolyte Physiology, Vol. 262, No. 1, 1992.

Research output: Contribution to journalArticle

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