Immunochemical demonstration of a novel beta-subunit isoform of X, K-ATPase in human skeletal muscle.
Recently we have identified mRNA encoding a hitherto unknown mammalian X,K-ATPase beta-subunit expressed predominantly in muscle tissue (Pestov, N. B. et al. (1999) FEBS Lett. 456, 243-248). Here we demonstrate the existence of the predicted protein, designated as beta(m) (beta(muscle)), in human adult skeletal muscle membranes using immunoblotting with beta(m)-specific antibodies generated against recombinant polypeptide formed by extramembrane beta(m) domains. The electrophoretic mobility of beta(m) was shown to be abnormally low due to the presence of Glu-rich sequences. In contrast to mature forms of other known X,K-ATPase beta-subunits, carbohydrate moiety of beta(m) is sensitive to endoglycosidase H and appears to be composed of short high-mannose or hybrid N-glycans. This finding argues in favor of an intracellular location of beta(m) in human skeletal muscle.
Pestov
N B
NB
Department of Pharmacology, Medical College of Ohio, Toledo, Ohio 43614, USA.
Korneenko
T V
TV
Zhao
H
H
Adams
G
G
Shakhparonov
M I
MI
Modyanov
N N
NN
D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002384:Catalysis; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D018698:Glutamic Acid / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000378:metabolism; D006031:Glycosylation; D017506:H(+)-K(+)-Exchanging ATPase / Q000096:biosynthesis* / Q000737:chemistry*; D006801:Humans; D015151:Immunoblotting; D008358:Mannose / Q000737:chemistry; D008875:Middle Aged; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D000254:Sodium-Potassium-Exchanging ATPase / Q000096:biosynthesis* / Q000737:chemistry*
D011134:Polysaccharides; D020033:Protein Isoforms; D011994:Recombinant Proteins; D018698:Glutamic Acid; D006026:Glycoside Hydrolases; D017506:H(+)-K(+)-Exchanging ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D008358:Mannose