Arrestins and spinophilin competitively regulate Na+,K+-ATPase trafficking through association with a large cytoplasmic loop of the Na+,K+-ATPase.
The activity and trafficking of the Na(+),K(+)-ATPase are regulated by several hormones, including dopamine, vasopressin, and adrenergic hormones through the action of G-protein-coupled receptors (GPCRs). Arrestins, GPCR kinases (GRKs), 14-3-3 proteins, and spinophilin interact with GPCRs and modulate the duration and magnitude of receptor signaling. We have found that arrestin 2 and 3, GRK 2 and 3, 14-3-3 epsilon, and spinophilin directly associate with the Na(+),K(+)-ATPase and that the associations with arrestins, GRKs, or 14-3-3 epsilon are blocked in the presence of spinophilin. In COS cells that overexpressed arrestin, the Na(+),K(+)-ATPase was redistributed to intracellular compartments. This effect was not seen in mock-transfected cells or in cells expressing spinophilin. Furthermore, expression of spinophilin appeared to slow, whereas overexpression of beta-arrestins accelerated internalization of the Na(+),K(+)-ATPase endocytosis. We also find that GRKs phosphorylate the Na(+),K(+)-ATPase in vitro on its large cytoplasmic loop. Taken together, it appears that association with arrestins, GRKs, 14-3-3 epsilon, and spinophilin may be important modulators of Na(+),K(+)-ATPase trafficking.
Kimura
Tohru
T
Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026, USA.
Allen
Patrick B
PB
Nairn
Angus C
AC
Caplan
Michael J
MJ
D048948:14-3-3 Proteins / Q000378:metabolism; D000818:Animals; D019393:Arrestin / Q000378:metabolism*; D001667:Binding, Competitive; D002460:Cell Line; D002522:Chlorocebus aethiops; D002831:Choroid Plexus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism*; D054768:G-Protein-Coupled Receptor Kinases / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D011817:Rabbits; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism*; D000099273:Neurabins