2001 Fiscal Year Final Research Report Summary
Mechanism, Intracellular Transport and Physiological Function of P-type ATPase
| Project/Area Number |
10480168
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Functional biochemistry
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
MAEDA Masatomo Osaka University, Graduate School of pharmaceutical Sciences, Professor, 薬学研究科, 教授 (80190297)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Ayako Osaka University, Graduate School of pharmaceutical Sciences, Lecturer, 薬学研究科, 講師 (90272484)
|
|---|
| Project Period (FY) |
1998 – 2001
|
| Keywords | P-ATPase / H^+ / K^+-ATPase / Cl^--channel / Intracellular Transport / Proton Pump / Mat-8 / gastric Mucosal Cells |
|---|
| Research Abstract |
1) The gastric proton pump was expressed in CHO-K1 cells. Such cell could grow in the presence of ouabain, since proton pump functions in place of sodium pump. Proton pump inhibitor, omeprazol, together with ouabain inhibited the cell growth, consisting with their inhibitory effects on proton pump and sodium pump, respectively. This system would be useful for study the effect of proton pump inhibitor.
2) Primary structure of pig Mat-8 that highly expresses in stomach was determined. This single transmembrane protein mainly expresses in mucous cells but not parietal cells. Thus it is interesting to know how Mat-8 functions in Cl^- transport in gastric acid (HCl) secretion and mucous secretion, since Xenopus oocyte injected with Mat-8 mRNA showed Cl^- channel activity. Examination of cellular distribution demonstrated that the fusion protein of Mat-8 with DS-Red localized in endoplasmic reticulum and cytoplasmic vesicles. We further studied to find the component(s) interacting with Mat-8 by yeast two-hybrid system. At present we found several clones that interact with cytoplasmic domain of Mat-8. We are interested in what proteins are encoded by these clones.
3) Effect of K^+ concentration on the degradation of EP was determined with the αβ complex expressed in insect cells. Comparison of hybrids with pig and rat subunits demonstrated that the complex with rat β subunit degraded EP in the presence of lower concentration of K^+. The β subunit has a role in K^+ sensitivity in the reaction cycle of the gastric proton pump.
|
