TY - JOUR
T1 - Effects of lovastatin on trafficking of cystic fibrosis transmembrane conductance regulator in human tracheal epithelium
AU - Shen, Ben Quan
AU - Widdicombe, Jonathan H.
AU - Mrsny, Randall J.
PY - 1995/10/20
Y1 - 1995/10/20
N2 - Genetic defects in the cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated chloride channel, cause cystic fibrosis. Most defective forms of CFTR show improper intracellular trafficking. Because isoprenylated, small GTP-binding proteins are involved in the vesicular trafficking of other integral membrane proteins, we have investigated the role of isoprenylation in the trafficking of CFTR to the apical membranes of primary cultures of human airway epithelium and of Calu-3 cells, a human lung carcinoma cell line. CFTR function was measured as short circuit current. 125I efflux, and conductance of cell sheets with permeabilized basolateral membranes. Lovastatin, an inhibitor of isoprenyl lipid biosynthesis, markedly inhibited all measures of CFTR function. The lovastatin, induced declines in CFTR function were corrected by the simultaneous addition of mevalonate or the isoprenyl lipids geranylgeranyl and farnesyl but not cholesterol. Lovastatin reduced total cellular CFTR as assessed by immunoprecipitation. Mevalonate or isoprenyl lipids protected CFTR levels from the actions of lovastatin. Together, these results suggest a role for isoprenyl lipids, presumably through the actions of small GTP-binding proteins, in the trafficking of CFTR to the apical membrane of human airway epithelium.
AB - Genetic defects in the cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated chloride channel, cause cystic fibrosis. Most defective forms of CFTR show improper intracellular trafficking. Because isoprenylated, small GTP-binding proteins are involved in the vesicular trafficking of other integral membrane proteins, we have investigated the role of isoprenylation in the trafficking of CFTR to the apical membranes of primary cultures of human airway epithelium and of Calu-3 cells, a human lung carcinoma cell line. CFTR function was measured as short circuit current. 125I efflux, and conductance of cell sheets with permeabilized basolateral membranes. Lovastatin, an inhibitor of isoprenyl lipid biosynthesis, markedly inhibited all measures of CFTR function. The lovastatin, induced declines in CFTR function were corrected by the simultaneous addition of mevalonate or the isoprenyl lipids geranylgeranyl and farnesyl but not cholesterol. Lovastatin reduced total cellular CFTR as assessed by immunoprecipitation. Mevalonate or isoprenyl lipids protected CFTR levels from the actions of lovastatin. Together, these results suggest a role for isoprenyl lipids, presumably through the actions of small GTP-binding proteins, in the trafficking of CFTR to the apical membrane of human airway epithelium.
UR - http://www.scopus.com/inward/record.url?scp=0028792383&partnerID=8YFLogxK
U2 - 10.1074/jbc.270.42.25102
DO - 10.1074/jbc.270.42.25102
M3 - Article
C2 - 7559642
AN - SCOPUS:0028792383
SN - 0021-9258
VL - 270
SP - 25102
EP - 25106
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 42
ER -