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CFTR and V‐ATPase trafficking and function in the intestinal brush border membrane
Author(s) -
Collaco Anne,
Geibel Peter,
Kravtsov Dmitri,
Ghantaphang Sayali,
Lee Beth,
Geibel John,
Ameen Nadia
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.913.10
Subject(s) - cystic fibrosis transmembrane conductance regulator , apical membrane , chemistry , brush border , intracellular , atpase , ion transporter , enterocyte , epithelial polarity , endosome , intracellular ph , microbiology and biotechnology , v atpase , biochemistry , biology , membrane , small intestine , enzyme , vesicle , gene
The multi‐subunit proton pump, vacuolar ATPase (V‐ATPase) and the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel are both regulated by cAMP‐dependent traffic from endosomes to the plasma membrane in ion transporting epithelia. We hypothesized that V‐ATPase traffic and function are linked to CFTR in the intestine. The distribution of V‐ATPase V o a 1, V o a 2 and V 1 E subunits and CFTR were examined in wild‐type (WT), CFTR −/− mouse intestine and polarized intestinal CaCo‐2 BB e cells following cAMP stimulation. Functional dependence of V‐ATPase on CFTR was determined in CaCo‐2 BB e cells using the pH sensitive dye BCECF. Co‐immunoprecipitation confirmed V o a 1, V o a 2 and V 1 E interaction with CFTR. V‐ATPase V o a 1 and V o a 2 subunits were localized to the apical and basolateral domains in CaCo‐2 BB e cells. V‐ATPase V o a 1 and V o a 2 subunits were localized to distinct domains in untreated and treated enterocytes from WT and CFTR −/− intestine. Following cAMP activation, both transporters co‐localized in the apical membrane. Inhibition of V‐ATPase or CFTR significantly decreased proton efflux in CaCo2 BB e cells. These studies suggest functional synergy between both transporters in maintaining intracellular pH; and localization in the intestinal brush border membrane. NIH Grants: R01‐DK‐077065 to N. Ameen and P30‐DK‐34989 to the Yale Liver Center.