| Budget Amount *help |
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1987: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1986: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
Parietal cell seretes HC19 H,K-ATPase is an active H^+ pump in the apical membranes of the parietal cell. We found that tubulovesicles in the cell at the resting state C1^- channel in abbition to the H,K-ATPase and that the C1^- channel can be repoened by S-S cross-linking. We raised several monoclonal antibodies against tubulovesicles. One of them desiganted HK2032 partially inhibited H,K-ATPase and completely inhibited the C1^- channel. Present inhibition og both H,K-ATPade activity and the C1^- channel was direct evidence for that the C1^- channel was oart of the function of H,K-ATPase. Since Since Na,K-ATPase and Ca^<2+>-ATPase do not contain anion channel, the nature of H,K-ATPase is very specific. The C-terminal regions of the amino acid sequence of H,K-ATPase is very rich in cystein, which may engage in S-S<-->2SH (open<-->close) transformation of the C1 channel. The property of tubulovesicles in which C1^- channel was opened by cross-linking was the same as that of apical membrane vesicles in which C1^- channel was opened (without chemical modifications), indicationg that the fusion of tubulocesicles with the apical membrane occurs in the process of atimulation and it accompanies increase in C1^- conductance. An immunological study also showed that both H,K-ATPases in tubulovesicles and the apical membrane were wht same. %furthermore we obtained monoclonal antibodu HK4001 which completely inhibited H,K-ATPase activity and partially inhibited the C1^- conductance. Finally patch clamp study with monoclonal antibodies are in progress.
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