Association of renal Na,K-ATPase alpha-subunit with the beta- and gamma-subunits based on cryoelectron microscopy.
Na,K-ATPase transports Na(+) and K(+) across cell membranes and consists of alpha- and beta-subunits. Na,K-ATPase also associates with small FXYD proteins that regulate the activity of the pump. We have used cryoelectron microscopy of two-dimensional crystals including data to 8 A resolution to determine the three-dimensional (3-D) structure of renal Na,K-ATPase containing FXYD2, the gamma-subunit. A homology model for the alpha-subunit was calculated from a Ca(2+)-ATPase structure and used to locate the additional beta- and gamma-subunits present in the 3-D map of Na,K-ATPase. Based on the 3-D map, the beta-subunit is located close to transmembrane helices M8 and M10 and the gamma-subunit is adjacent to helices M2 and M9 of the alpha-subunit.
Purhonen
P
P
Department of Biosciences and Nutrition and School of Technology and Health, Karolinska Institutet, Royal Institute of Technology, S-141 57, Huddinge, Sweden.
Thomsen
K
K
Maunsbach
A B
AB
Hebert
H
H
D000818:Animals; D020285:Cryoelectron Microscopy; D007668:Kidney / Q000737:chemistry*; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000648:ultrastructure*; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry*; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry*; D013552:Swine
D046912:Multiprotein Complexes; D021122:Protein Subunits; D000254:Sodium-Potassium-Exchanging ATPase