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Stimulation of ouabain‐sensitive 86 Rb + uptake and Na + ,K + ‐ATPase α‐subunit phosphorylation by a cAMP‐dependent signalling pathway in intact cells from rat kidney cortex
Author(s) -
Carranza Maria Luisa,
Féraille Eric,
Kiroytcheva Militza,
Rousselot Martine,
Favre Hervé
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)01121-0
Subject(s) - ouabain , phosphorylation , protein subunit , stimulation , chemistry , atpase , biophysics , microbiology and biotechnology , biochemistry , biology , enzyme , endocrinology , sodium , organic chemistry , gene
We investigated in intact cortical kidney tubules the role of PKA‐mediated phosphorylation in the short‐term control of Na + ,K + ‐ATPase activity. The phosphorylation level of Na + ,K + ‐ATPase was evaluated after immunoprecipitation of the enzyme from 32 P‐labelled cortical tubules and the cation transport activity of Na + ,K + ‐ATPase was measured by ouabain‐sensitive 86 Rb + uptake. Incubation of cells with CAMP analogues (8‐bromo‐cAMP, dibutyryl‐cAMP) or with forskolin plus 3‐isobutyl‐1‐methylxanthine increased the phosphorylation level of the Na + ,K + ‐ATPase α‐subunit and stimulated ouabain‐sensitive 86 Rb + uptake. Inhibition of PKA by H‐89 blocked the effects of dibutyryl‐cAMP on both phosphorylation and 86 Rb + uptake processes. The results suggest that phosphorylation by PKA stimulates the Na + ,K + ‐ATPase activity.