cAMP-dependent exocytosis and vesicle traffic regulate CFTR and fluid transport in rat jejunum in vivo

The cystic fibrosis transmembrane conductance regulator (CFTR) channel is regulated by cAMP-dependent vesicle traffic and exocytosis to the apical membrane in some cell types, but this has not been demonstrated in the intestinal crypt. The distribution of CFTR, lactase (control), and fluid secretion...

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Bibliographic Details
Published inAmerican Journal of Physiology: Cell Physiology Vol. 53; no. 2; pp. C429 - C438
Main Authors AMEEN, Nadia A, MARINO, Christopher, SALAS, Pedro J. I
Format Journal Article
LanguageEnglish
Published Bethesda, MD American Physiological Society 01.02.2003
Subjects
Biological and medical sciences
Cells
Cystic fibrosis
Fundamental and applied biological sciences. Psychology
Intestine. Mesentery
Membranes
Rodents
Vertebrates: digestive system
intestine
Rat
Digestive system
Secretion
Mucosa
Biological transport
Rodentia
Cyclic AMP
Exocytosis
Small intestine
Apical membrane
Vertebrata
Mammalia
Jejunum
Animal
Cystic fibrosis transmembrane conductance regulator
Cytoplasmic vesicle
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Summary:The cystic fibrosis transmembrane conductance regulator (CFTR) channel is regulated by cAMP-dependent vesicle traffic and exocytosis to the apical membrane in some cell types, but this has not been demonstrated in the intestinal crypt. The distribution of CFTR, lactase (control), and fluid secretion were determined in rat jejunum after cAMP activation in the presence of nocodazole and primaquine to disrupt vesicle traffic. CFTR and lactase were localized by immunofluorescence, and surface proteins were detected by biotinylation of enterocytes. Immunoprecipitates from biotinylated and nonbiotinylated cells were analyzed by streptavidin detection and immunoblots. Immunolocalization confirmed a cAMP-dependent shift of CFTR but not lactase from a subapical compartment to the apical surface associated with fluid secretion that was reduced in the presence of primaquine and nocodazole. Analysis of immunoblots from immunoprecipitates after biotinylation revealed a 3.8 ± 1.7-fold (P < 0.005) increase of surface-exposed CFTR after vasoactive intestinal peptide (VIP). These measurements provide independent corroboration supporting a role for vesicle traffic in regulating CFTR and cAMP-induced fluid transport in the intestine.
ISSN:0363-6143
1522-1563