Abstract |
Autosomal dominant polycystic kidney disease ( ADPKD) is caused by genetic mutations in either PKD1 or PKD2, the genes that encode polycystin-1 (PC-1) and polycystin-2 (PC-2), respectively. ADPKD is characterized by the formation of multiple, progressive, fluid-filled renal cysts. To elucidate the mechanism of fluid secretion by ADPKD cysts, we examined the effect of PC-1 on the plasma membrane expression of cystic fibrosis transmembrane conductance regulator (CFTR), a key Cl(-) secretory protein. Five stably transfected MDCK lines were used in this study: two transfected with empty vector (control cells) and three expressing human PC-1 (PC-1 cells). The cAMP-induced endogenous short circuit currents (I(sc)) were smaller in PC-1 cells than in control cells. Compared to control cells, PC-1 cells transiently expressing pEGFP-CFTR showed significant reduction of whole cell cAMP-activated Cl(-) currents. Cell surface biotinylation experiments also indicated a reduction in surface expression of CFTR in PC-1 cells compared to control. Furthermore, studies using CHO cells transiently expressing PC-1 and CFTR suggest the importance of the PC-1 COOH-terminus in the observed reduction of CFTR plasma membrane expression. No differences in either endogeneous K(+) currents or P2Y receptor responses were observed between PC-1 and control cells, indicating the specificity of PC-1's action. These results indicate that PC-1 selectively maintains low cell surface expression of CFTR. Moreover, these findings suggest that the malfunction of PC-1 enhances plasma membrane expression of CFTR, thus causing abnormal Cl(-)secretion into the cyst lumen.
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Authors | Masahiro Ikeda, Peying Fong, Jie Cheng, Alessandra Boletta, Feng Qian, Xue-Mei Zhang, Hui Cai, Gregory G Germino, William B Guggino |
Journal | Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology
(Cell Physiol Biochem)
Vol. 18
Issue 1-3
Pg. 9-20
( 2006)
ISSN: 1015-8987 [Print] Germany |
PMID | 16914886
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- Chloride Channels
- Recombinant Fusion Proteins
- TRPP Cation Channels
- polycystic kidney disease 1 protein
- Cystic Fibrosis Transmembrane Conductance Regulator
- Green Fluorescent Proteins
- Hepatocyte Growth Factor
- Cyclic AMP
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Topics |
- Animals
- CHO Cells
- Cell Line
- Cell Membrane
(metabolism, physiology)
- Chloride Channels
(genetics, physiology)
- Cricetinae
- Cricetulus
- Cyclic AMP
(pharmacology)
- Cystic Fibrosis Transmembrane Conductance Regulator
(genetics, physiology)
- Gene Expression
- Green Fluorescent Proteins
(genetics)
- Hepatocyte Growth Factor
(pharmacology)
- Humans
- Membrane Potentials
(drug effects)
- Recombinant Fusion Proteins
(genetics)
- TRPP Cation Channels
(metabolism)
- Transfection
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