FRET analysis reveals a critical conformational change within the Na,K‐ATPase α1 subunit N‐terminus during GPCR‐dependent endocytosis

Abstract
Dopamine is a major regulator of sodium reabsorption in proximal tubule epithelia. It induces the endocytosis of plasma membrane Na,K‐ATPase molecules, and this results in a reduced capacity of the cells to transport sodium. Dopamine induces the phosphorylation of Ser‐18 in the α1‐subunit of Na,K‐ATPase. Fluorescence resonance energy transfer analysis of cells expressing YFP‐α1 and β1‐CFP reveals that treatment of the cells with dopamine increases energy transfer between CFP and YFP. This is consistent with a protein conformational change that results in the N‐terminal end of α1 moving closer to the internal face of the plasma membrane.