| Project/Area Number |
18590380
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Experimental pathology
|
|---|
| Research Institution | Juntendo University |
|---|
Principal Investigator |
KOBAYASHI Toshiyuki Juntendo University, Grad. Sch. Med., Associate Professor (40260070)
|
|---|
| Project Period (FY) |
2006 – 2007
|
| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥4,020,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Keywords | BHDsyndrome / FnipL / mTOR / AMPK / Tsc2 / Fnip 1 / Bhd症候群 / Fnip1 / 腎癌 / Bhd / Nihonラット / Ekerラット / 動物モデル / リン酸化 |
|---|
| Research Abstract |
In this study, a novel Bhd product (Flcn)-binding protein (Fnipl-like protein = FnipL) was identified by homology search and its binding with Flcn and AMPK was characterized. The interaction between FnipL and Flcn may be mediated mainly by the C-terminal domains of each proteins as well as Flcn-Fnipl interaction. Ectopically expressed Flcn was localized mainly in the nucleus. Co-transfection analysis revealed that Hen is localized to the cytoplasm by FnipL or Fnipl. A deletion of carboxy-terminal Flcn-binding domain in FnipL cancelled cytoplasmic localization of Flcn, suggesting that the Fnip proteins regulate localization of Flcn through the complex formation. By the employment of siRNA, a decrease in S6K1 phosphorylation in the BHD-suppressed cell was observed. A decrease in S6K1 phosphorylation in FNIPL- or FN/P/ -suppressed cells was also observed. These results suggest that Flcn-FnipL and Flcn-Fnipl complexes positively regulate S6K1 phosphorylation. We also analyzed phosphorylation of Flcn. Phosphorylation of Flcn was suppressed by rapamycin-treatment or expression of Tsc2 in the Tsc2-deficient renal carcinoma cells. Forced expression of Rheb in 293 cells induced Flcn phosphorylation. Conversely, RNAi-mediated inhibition of raptor reduced Flcn phosphorylation. These results suggest that Tsc2-mTOR pathway regulates Flcn phosphorylation. By site-directed mutagenesis and mass spectrometry revealed that a serine residue in the amino-terminal region is a major phosphorylation site. However phosphorylation of this site was thought to be not regulated by Tsc2-mTOR. Several other candidate phosphorylation sites were identified. Together, in this study, reciplocal functional relationship between Flcn and mTOR has been revelead as a clue to elucidate the molecular mechanism of carcinogenesis associated with BHD-deficiency.
|
