PKCα regulates TMEM16A-mediated Cl- secretion in human biliary cells

Amal K. Dutta, Al Karim Khimji, Songling Liu, Zemfira Karamysheva, Akiko Fujita, Charles Kresge, Don C. Rockey, Andrew P. Feranchak

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

TMEM16A is a newly identified Ca2+-activated Cl channel in biliary epithelial cells (BECs) that is important in biliary secretion. While extracellular ATP stimulates TMEM16A via binding P2 receptors and increasing intracellular Ca2+ concentration ([Ca2+]i), the regulatory pathways have not been elucidated. Protein kinase C (PKC) contributes to ATP-mediated secretion in BECs, although its potential role in TMEM16A regulation is unknown. To determine whether PKCα regulates the TMEM16A-dependent membrane Cltransport in BECs, studies were performed in human biliary Mz-cha-1 cells. Addition of extracellular ATP induced a rapid translocation of PKCα from the cytosol to the plasma membrane and activation of whole cell Ca2+-activated Cl currents. Currents demonstrated outward rectification and reversal at 0 mV (properties consistent with TMEM16A) and were inhibited by either molecular (siRNA) or pharmacologic (PMA or Gö6976) inhibition of PKCα. Intracellular dialysis with recombinant PKCα activated Cl currents with biophysical properties identical to TMEM16A in control cells but not in cells after transfection with TMEM16A siRNA. In conclusion, our studies demonstrate that PKCα is coupled to ATP-stimulated TMEM16A activation in BECs. Targeting this ATP-Ca2+-PKCα signaling pathway may represent a therapeutic strategy to increase biliary secretion and promote bile formation.

Original languageEnglish (US)
Pages (from-to)G34-G42
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume310
Issue number1
DOIs
StatePublished - Jan 1 2016

Keywords

  • ATP
  • Cl channel
  • PKCα
  • TMEM16A
  • cholangiocytes

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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