| 1.Research Institution | The University of Tokyo | |
| 2.Research Area | Life Sciences | |
| 3.Research Field | Cellular Signaling | |
| 4.Term of Project | FY1996〜FY2000 | |
| 5.Project Number | 96L00308 | |
| 6.Title of Project | Molecular interaction of inositolphospholipids with signal proteins |
| Name | Institution,Department | Title of Position |
| Tadaomi, Takenawa | The University of Tokyo, The Institute of Medical Science | Professor |
8.Core Members
| Names | Institution,Department | Title of Position |
| Kiyoko, Fukami | The University of Tokyo, The Institute of Medical Science | Lecture |
9.Cooperating Researchers
| Names | Institution,Department | Title of Position |
| Yasuhiro, Mochizuki | The University of Tokyo, The Institute of Medical Science | Post Doctor |
10.Summary of Research Results
|
To elucidate the new functions of PI(4,5)P2, we surveyed the new PI(4,5)P2 binding domains. It is already well known that PH domains act as PI(4,5)P2 binding domains, which are contained in a variety of proteins. Here, we found that ENTH domain contained in epsin bound to PI(4,5)P2. The ENTH domain also bound to PI(3,4,5)P3 but not other inositolphosphatides. We further investigated the 3 dimentional structure of the ENTH domain by NMR. The ENTH domain consists of 6 a-helix. In the binding to PI(4,5)P2, N-terminal unstructural region and the loop between helix 3 and 4 play important roles. Substitution of basic amino acids including those areas to alanine completely diminished the binding activity. Epsin was known to be essential for the vesicle formation induced by clathrin complexes. To demonstrate PI(4,5)P2 binding is crucial for the vesicle formation, we studied the effect on the internalization of EGF in PI(4,5)P2-bining lost mutant expressing cells. That mutant inhibited the internalization strongly. All these data show that Epsin ENTH domain is PI(4,5)P2 binding domain and its binding is essential for endocytosis. |
11.Key Words
(1)PI(4,5)P2 binding、(2)Endocytosis、(3)Epsin
(4)ENTH domain、(5)Domain structure
12.References
| Author | Title of Article | |||
| Park, S | Phosphatidylinositol 4-phosphate 5-kinase type I is regulated through phosphorylation response by extracellular stimuli | |||
| Journal | Volume | Year | Pages Concerned | |
| J. Biol. Chem. | 274 | 2001 | 4781-4787 | |
| Author | Title of Article | |||
| Itoh, T. | The Epsin N-terminal homology(ENTH) domain:a Phosphatidylinositol 4, 5-bisphosphate binding domain esential for endocytosis | |||
| Journal | Volume | Year | Pages Concerned | |
| Science | 291 | 2001 | 1047-1051 | |
| Author | Title of Article | |||
| Zhang, Y. | Phosphatidylinositol 4-phosphate 5-kinase its3 and calcineurin ppb1 coordinately regulate cytokinesis in fission yeast. | |||
| Journal | Volume | Year | Pages Concerned | |
| J. Biol. Chem. | 275 | 2000 | 35600-35606 | |
| Author | Title of Article | |||
| Ijyuuin, T. | Identification and characterization of a novel inositol polyphosphate 5-phosphatase. | |||
| Journal | Volume | Year | Pages Concerned | |
| J. Biol. Chem. | 275 | 2000 | 10870-10875 | |
| Author | Title of Article | |||
| Fukami, K. | Growth factor-induced promoter activation of murine phospholipase C delta4 gene. | |||
| Journal | Volume | Year | Pages Concerned | |
| Eur J Biochem. | 267 | 2000 | 28-36 | |