Elevated K+ induces myristoylated alanine-rich C-kinase substrate phosphorylation and phospholipase D activation in glomerulosa cells

Soraya Betancourt-Calle, Eun Mi Jung, Stephanie White, Sagarika Ray, Xiangjian Zheng, Roberto A. Calle, Wendy B. Bollag

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Elevated extracellular potassium concentrations ([K+]e) are known to stimulate aldosterone secretion from adrenal glomerulosa cells in vivo and in vitro. The mechanism is thought to involve depolarization-elicited activation of voltage-dependent calcium channels and an increase in calcium influx. Until now protein kinase C (PKC) was thought not to play a role in the steroidogenic response to elevated [K+]e. In this report, we provide evidence in bovine adrenal glomerulosa cells to suggest that elevated [K+]e increases PKC activity, as shown by an enhancement in the phosphorylation of myristoylated alanine-rich C-kinase substrate (MARCKS). Elevated [K+]e-induced MARCKS phosphorylation was delayed and transient and was not the result of a local production of angiotensin II (AngII). MARCKS phosphorylation in response to elevated [K+]e was not accompanied by phosphoinositide hydrolysis but was inhibited by a selective PKC inhibitor. Elevated [K+]e also activated phospholipase D (PLD) in a delayed but sustained manner. We propose that the observed PLD activation mediates the elevated [K+]e-induced MARCKS phosphorylation via PKC, although other factors may modulate this phosphorylation event.

Original languageEnglish (US)
Pages (from-to)65-76
Number of pages12
JournalMolecular and Cellular Endocrinology
Volume184
Issue number1-2
DOIs
StatePublished - Nov 26 2001

Keywords

  • Aldosterone
  • Angiotensin II
  • Calcium channels
  • Protein kinase C

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology

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