Cholangiocytes exhibit dynamic, actin-dependent apical membrane turnover

R. Brian Doctor, Rolf Dahl, Laura Fouassier, Gordan Kilic, J. Gregory Fitz

Research output: Contribution to journalArticle

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Abstract

The present studies of cholangiocytes used complementary histological, biochemical, and electrophysiological methods to identify a dense population of subapical vesicles, quantify the rates of vesicular trafficking, and assess the contribution of the actin cytoskeleton to membrane trafficking. FM 1-43 fluorescence measured significant basal rates of total exocytosis (1.33 ± 0.16% plasma membrane/min) in isolated cholangiocytes and apical exocytosis in cholangiocyte monolayers. Cell surface area remained unchanged, indicating that there was a concurrent, equivalent rate of endocytosis. FM 1-43 washout studies showed that 36% of the endocytosed membrane was recycled to the plasma membrane. 8-(4-Chlorophenylthio)adenosine 3′,5′-cyclic monophosphate (CPT-cAMP; cAMP analog) increased exocytosis by 71 ± 31%, whereas the Rp diastereomer of adenosine 3′,5′-cyclic monophosphothioate (Rp-cAMPS; protein kinase A inhibitor) diminished basal exocytosis by 53 ± 11%. A dense population of 140-nm subapical vesicles arose, in part, from apical membrane endocytosis. Phalloidin staining showed that a sub-population of the endocytosed vesicles was encapsulated by F-actin. Furthermore, membrane trafficking was inhibited by disrupting the actin cytoskeleton with cytochalasin D (51 ± 13% of control) or jasplakinolide (58 ± 9% of control). These studies indicate that there is a high rate of vesicular trafficking at the apical membrane of cholangiocytes and suggest that both cAMP and the actin cytoskeleton contribute importantly to these events.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume282
Issue number5 51-5
StatePublished - 2002

Fingerprint

Exocytosis
Actins
Endocytosis
Membranes
Actin Cytoskeleton
jasplakinolide
Cell membranes
Adenosine
Cell Membrane
Population
Phalloidine
Cytochalasin D
Protein Kinase Inhibitors
Cyclic AMP-Dependent Protein Kinases
Monolayers
Fluorescence
Staining and Labeling
FM1 43

Keywords

  • Endocytosis
  • Exocytosis
  • Vesicular trafficking

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology

Cite this

Cholangiocytes exhibit dynamic, actin-dependent apical membrane turnover. / Brian Doctor, R.; Dahl, Rolf; Fouassier, Laura; Kilic, Gordan; Gregory Fitz, J.

In: American Journal of Physiology - Cell Physiology, Vol. 282, No. 5 51-5, 2002.

Research output: Contribution to journalArticle

Brian Doctor, R. ; Dahl, Rolf ; Fouassier, Laura ; Kilic, Gordan ; Gregory Fitz, J. / Cholangiocytes exhibit dynamic, actin-dependent apical membrane turnover. In: American Journal of Physiology - Cell Physiology. 2002 ; Vol. 282, No. 5 51-5.
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