| Project/Area Number |
17580259
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Basic veterinary science/Basic zootechnical science
|
|---|
| Research Institution | University of Miyazaki |
|---|
Principal Investigator |
IKEDA Masahiro University of Miyazaki, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (60281218)
|
|---|
| Project Period (FY) |
2005 – 2006
|
| Project Status |
Completed (Fiscal Year 2006)
|
| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
|
|---|
| Keywords | aquaporin / water channel / AQP11 / intracellular localization / endoplasmic reticulum / cross-linker / multimer |
|---|
| Research Abstract |
Aquaporin-11 (AQP11) was recently identified and shown to be expressed at the proximal tubule in the kidney. AQP11-null mice do not survive past the neonatal period, presumably due to renal failure associated with renal cysts. AQP11 has several unique amino acid sequence patterns including an asparagine-proline-cysteine (NPC) motif that corresponds to the N-terminal asparagine-proline-alanine (NPA) motif of conventional AQPs, a signature motif of the AQPs, as well as a C-terminal di-lysine motif (NKKE) which resembles the KKXX ER-retention signal. In this study we evaluated the roles of NPC and NKKE motifs in the subcellular localization and oligomerization of AQP11. Western blotting of protein fractions resulting from differential centrifugation of the whole kidney homogenate revealed the intracellular localization of AQP11. Both confocal microscopic studies and cell surface biotinylation experiments with cells transiently expressing AQP11 also supported the intracellular, especially ER-located AQP11. Co-immunoprecipitation and chemical cross-linking experiments showed the oligomeric structure of AQP11. Site-directed mutation at the NPC or the NKKE motif did not direct AQPll to the plasma membrane. Mutation at the NKKE motif had no significant effect on oligomerization, while the C101A mutation in the NPC motif reduced oligomerization of AQPll. Although the NPA motif is known to be important for a water-permeable pore formation, our observations suggest that the corresponding NPC motif of AQP11 also has a role in its 3-D protein structure.
|
