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CFTR and ClC‐5 Chloride Channels Modulate Plasma Membrane H+‐ATPase in Proximal Tubule Cells
Author(s) -
CarraroLacroix Luciene Regina,
Lessa Lucília M.,
Pessoa Thaíssa D.,
Nogueira Camila,
SouzaMenezes Jackson,
Morales Marcelo M.,
Girardi Adriana C.,
Malnic Gerhard
Publication year - 2010
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.24.1_supplement.815.11
Subject(s) - chemistry , biophysics , membrane , valinomycin , reabsorption , atpase , endocytosis , chloride channel , membrane potential , biochemistry , cell , enzyme , sodium , biology , organic chemistry
H+ transport across membranes by H‐ATPase creates a lumen‐positive voltage, generating an electrochemical potential gradient that limits pump activity. This DP is normally dissipated by a Cl‐ movement, which provides an electric shunt compensating for the transferred positive charge. This work was performed to identify the associated Cl−‐conducting proteins involved in the regulation of plasma membrane (PM) H‐ATPase from rat kidney proximal tubule (PT). Through in vivo stationary microperfusion, it was observed that ATPase‐mediated HCO3− reabsorption was significantly reduced in the presence of the Cl− channels inhibitor NPPB. This effect was confirmed in vitro by measuring the cell pH recovery rates after NH4Cl pulse in a cultured cell line derived from PT, IRPTC. In these cells, even after abolishing the membrane potential with valinomycin, ATPase activity was seen to be still dependent on Cl−. siRNA‐mediated CFTR and ClC‐5 channels knockdown significantly reduced H‐ATPase activity. These results indicate that PM H‐ATPase activity from PT depends on both CFTR and ClC‐5 chloride channels. Supported by FAPESP