2006 Fiscal Year Final Research Report Summary
Molecular Mechanisms of Intracellular Sorting and Transport of Membrane Proteins
| Project/Area Number |
14104023
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (S)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Cell biology
|
|---|
| Research Institution | The University of Tokyo (2003-2006)
The Institute of Physical and Chemical Research (2002) |
|---|
Principal Investigator |
NAKANO Akihiko The University of Tokyo, Graduate School of Science, Department of Biological Sciences, Professor, 大学院理学系研究科, 教授 (90142140)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HIGASHIYAMA Tetsuya The University of Tokyo, Graduate School of Science, Department of Biological Sciences, Research Associate, 大学院理学系研究科, 助手 (00313205)
HIRATA Ryogo RIKEN Discovery Research Institute, Molecular Membrane Biology Laboratory, Senior Research Scientist, 中野生体膜研究室, 先任研究員 (60260197)
SATO Ken RIKEN Discovery Research Institute, Molecular Membrane Biology Laboratory, Research Scientist, 中野生体膜研究室, 研究員 (00303602)
|
|---|
| Project Period (FY) |
2002 – 2006
|
| Keywords | protein secretion / cargo sorting / COPII vesicles / cell-free reconstitution / Sarl GTPase / the Golgi apparatus / cisternal maturation / imaging |
|---|
| Research Abstract |
Mainly working on budding yeast, we obtained the following results regarding sorting mechanisms of membrane proteins.
1)Study on Rerlp sorting receptor. We showed that Rerlp is the machinery that binds a subset of ER-resident membrane proteins when they are mistransported to the Golgi, by directly recognizing polar residue motifs in their TMD, and send them back to the ER.
2)Study on lectin-type sorting receptors. We suggested that Emp46/47p act as receptors for a subset of glycoproteins during ER-Golgi recycling and showed that their oligomerization status is important for their trafficking.
3)Complete reconstitution of membrane-cargo sorting during COPII budding. We reconstituted COPII vesicle budding in a cell-free system comprising only pure proteins and lipids in a cargo-dependent manner. By this assay, we demonstrated that GTP hydrolysis by Sarlp plays a proof-reading role in cargo selection.
4)Roles of lipids and ubiquitin in membrane protein sorting. We showed that transport of plasma-membrane proteins, Tat2p and Pmalp, to the cell surface is regulated by ubiquitination and that sterol lipid plays an important role in this process.
5)Real-time visualization of membrane-protein sorting. Using a high-speed and high-sensitivity confocal laser scanning microscope we developed, we demonstrated that intra-Golgi transport of cargo proteins is performed by the cisternal maturation mechanism. We further showed that dynamic sorting and segregation of membrane are involved in this process in COPI-dependent and independent ways.
|
