Cyclic AMP stimulates K+ channel activity in mesophyll cells of Vicia faba L.

Weiwei Li, Sheng Luan, Stuart L. Schreiber, Sarah M. Assmann

Research output: Contribution to journalArticlepeer-review

62 Scopus citations

Abstract

Whole-cell patch-clamp recordings from Vicia faba mesophyll protoplasts reveal that outward K+ current is increased in a dose-dependent fashion by intracellular application of cAMP. The enhancement of the outward current by cAMP is specific and it cannot be mimicked by a series of nucleotides that includes AMP, cGMP, and GMP. The enhancement is evoked by micromolar concentrations of cAMP in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine. PKI or Walsh inhibitor, a specific peptide inhibitor of cAMP-dependent protein kinase (PKA), inhibits the outward K+ current. Adenosine 3′,5′-phosphothioate, a competitive inhibitor of PKA, has a similar effect. Conversely, the catalytic subunit of PKA (cAMP independent) from bovine brain enhances the magnitude of the outward K+ current in the absence of added cAMP. Our results indicate that cAMP modulates K+ channel activity in mesophyll cells and suggest that this modulation occurs through a cAMP-regulated protein kinase.

Original languageEnglish (US)
Pages (from-to)957-961
Number of pages5
JournalPlant physiology
Volume106
Issue number3
DOIs
StatePublished - Nov 1994

All Science Journal Classification (ASJC) codes

  • Physiology
  • Genetics
  • Plant Science

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