The Na+/K+-ATPase and the amyloid-beta peptide aβ1–40 control the cellular distribution, abundance and activity of TRPC6 channels

•Inhibition of the Na+/K+-ATPase changes the subcellular distribution of TRPC6 and triggers their degradation;•This is associated with reduced TRPC6-mediated Ca signals;•The amyloid beta peptide Aβ1–40, which inhibits the Na+/K+-ATPase, but not Aβ1–16, modifies TRPC6 distribution and activity;•In cortical neurons in cultures, ouabain and Aβ1–40 depress hyperforin-activated Ca responses;•Our data show the existence of a functional coupling between the Na+/K+-ATPase and TRPC6 channels

ABSTRACTThe Na+/K+-ATPase interacts with the non-selective cation channels TRPC6 but the functional consequences of this association are unknown. Experiments performed with HEK cells over-expressing TRPC6 channels showed that inhibiting the activity of the Na+/K+-ATPase with ouabain reduced the amount of TRPC6 proteins and depressed Ca2 + entry through TRPC6. This effect, not mimicked by membrane depolarization with KCl, was abolished by sucrose and bafilomycin-A, and was partially sensitive to the intracellular Ca2 + chelator BAPTA/AM. Biotinylation and subcellular fractionation experiments showed that ouabain caused a multifaceted redistribution of TRPC6 to the plasma membrane and to an endo/lysosomal compartment where they were degraded. The amyloid beta peptide Aβ1–40, another inhibitor of the Na+/K+-ATPase, but not the shorter peptide Aβ1–16, reduced TRPC6 protein levels and depressed TRPC6-mediated responses. In cortical neurons from embryonic mice, ouabain, veratridine (an opener of voltage-gated Na+ channel), and Aβ1–40 reduced TRPC6-mediated Ca2 + responses whereas Aβ1–16 was ineffective. Furthermore, when Aβ1–40 was co-added together with zinc acetate it could no longer control TRPC6 activity. Altogether, this work shows the existence of a functional coupling between the Na+/K+-ATPase and TRPC6. It also suggests that the abundance, distribution and activity of TRPC6 can be regulated by cardiotonic steroids like ouabain and the naturally occurring peptide Aβ1–40 which underlines the pathophysiological significance of these processes.