The Na,K-ATPase beta 2 subunit is expressed in rat brain and copurifies with Na,K-ATPase activity.
We have used a cloned fusion protein as antigen to generate an antiserum specific for the rat Na,K-ATPase beta 2 subunit. Utilizing this antiserum, we analyzed some of the structural features and tissue distribution of the beta 2 subunit. Treatment of a rat brain microsomal membrane fraction with N-glycanase F revealed that the beta 2 subunit is composed of an approximately 32 kDa core protein and at least two N-linked carbohydrate chains. The beta 2 subunit also was found to copurify with ouabain-inhibitable Na,K-ATPase activity from rat brain. Western blot analysis of rat tissue microsomes showed that beta 2 subunits were expressed in brain, pineal gland, and thymus. However, no beta 2 subunits were detected in kidney, heart, spleen, liver, mammary gland, or lung. These results suggest that the beta 2 subunit is a functional component of the rat brain Na,K-ATPase. The restricted tissue distribution of beta 2 subunits may reflect important differences in the functions of individual beta subunit isoforms.
Shyjan
A W
AW
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510.
Gottardi
C
C
Levenson
R
R
D000818:Animals; D000918:Antibody Specificity; D001921:Brain / Q000201:enzymology*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D007106:Immune Sera; D046911:Macromolecular Substances; D008861:Microsomes / Q000201:enzymology; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
D007106:Immune Sera; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins; D010042:Ouabain; D004247:DNA; D000254:Sodium-Potassium-Exchanging ATPase