Cyclic AMP increases cell surface expression of functional Na,K-ATPase units in mammalian cortical collecting duct principal cells

• Published in: Molecular biology of the cell 2001-02, Vol.12 (2), p.255-264
• Main Authors: Gonin, S, Deschênes, G, Roger, F, Bens, M, Martin, P Y, Carpentier, J L, Vandewalle, A, Doucet, A, Féraille, E
• Format: Article
• Language: English
• Subjects: Animals; Brefeldin A - pharmacology; Bucladesine - pharmacology; Calcium - metabolism; Cell Membrane - drug effects; Cell Membrane - metabolism; Cell Membrane Permeability - drug effects; Cells, Cultured; Cellular Biology; Chelating Agents - pharmacology; Cyclic AMP - metabolism; Egtazic Acid - analogs & derivatives; Egtazic Acid - pharmacology; In Vitro Techniques; Kidney Cortex - cytology; Kidney Cortex - drug effects; Kidney Cortex - metabolism; Life Sciences; Male; Mammals; Mice; Protein Synthesis Inhibitors - pharmacology; Rats; Rats, Wistar; Saponins - pharmacology; Sodium-Potassium-Exchanging ATPase - drug effects; Sodium-Potassium-Exchanging ATPase - metabolism; Temperature
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.12.2.255

Cyclic AMP (cAMP) stimulates the transport of Na(+) and Na,K-ATPase activity in the renal cortical collecting duct (CCD). The aim of this study was to investigate the mechanism whereby cAMP stimulates the Na,K-ATPase activity in microdissected rat CCDs and cultured mouse mpkCCD(c14) collecting duct cells. db-cAMP (10(-3) M) stimulated by 2-fold the activity of Na,K-ATPase from rat CCDs as well as the ouabain-sensitive component of (86)Rb(+) uptake by rat CCDs (1.7-fold) and cultured mouse CCD cells (1.5-fold). Pretreatment of rat CCDs with saponin increased the total Na,K-ATPase activity without further stimulation by db-cAMP. Western blotting performed after a biotinylation procedure revealed that db-cAMP increased the amount of Na,K-ATPase at the cell surface in both intact rat CCDs (1.7-fold) and cultured cells (1.3-fold), and that this increase was not related to changes in Na,K-ATPase internalization. Brefeldin A and low temperature (20 degrees C) prevented both the db-cAMP-dependent increase in cell surface expression and activity of Na,K-ATPase in both intact rat CCDs and cultured cells. Pretreatment with the intracellular Ca(2+) chelator bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid also blunted the increment in cell surface expression and activity of Na,K-ATPase caused by db-cAMP. In conclusion, these results strongly suggest that the cAMP-dependent stimulation of Na,K-ATPase activity in CCD results from the translocation of active pump units from an intracellular compartment to the plasma membrane.