Direct evidence for in vivo reversible tyrosine phosphorylation of the N-terminal domain of the H/K-ATPase alpha-subunit in mammalian stomach cells.
In vivo reversible phosphorylation of Tyr-7 and Tyr-10 of the pig stomach H/K-ATPase alpha-chain was initially demonstrated in mammals, rat, rabbit, and pig, in the presence of vanadate + H(2)O(2). In vitro phosphorylation has also been unequivocally demonstrated via the use of protease inhibitors during membrane H/K-ATPase preparation. An amphoretic detergent permitted each intrinsic kinase to phosphorylate each fusion protein containing the requisite Tyr residues, along with a reduction in alpha-chain phosphorylation. These and other data suggest that some important enzyme systems are present in the apical membrane and that they are in sufficient proximity to participate in the reversible phosphorylation of the amino terminal soluble domain of the alpha-chain with an unknown physiological function in the membrane embedded H/K-ATPase.
Kanagawa
M
M
Biological Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan.
Kaya
S
S
Umezu
H
H
Watanabe
S
S
Togawa
K
K
Shimada
A
A
Imagawa
T
T
Mårdh
S
S
Taniguchi
K
K
D000818:Animals; D002793:Cholic Acids / Q000494:pharmacology; D046508:Culture Techniques; D003902:Detergents / Q000494:pharmacology; D017506:H(+)-K(+)-Exchanging ATPase / Q000378:metabolism*; D008297:Male; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013270:Stomach / Q000201:enzymology*; D013552:Swine
D002793:Cholic Acids; D003902:Detergents; D011993:Recombinant Fusion Proteins; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases; D017506:H(+)-K(+)-Exchanging ATPase; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate