Molecular mechanism of regulation of growth factor receptor sorting at endosomes

内体生长因子受体分选调节的分子机制

基本信息

批准号：
17370045
负责人：
KITAMURA Naomi
金额：
$ 9.28万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17370045/
关键词：
growth factor receptor endosome endosomal sorting ubiquitination deubiquitinating enzyme UBPY ALG2 multivesicular body Hrs STAM複合体

项目摘要

Upon binding of growth factors to their cell surface receptors, the growth factor/receptor complexes are internalized and transported to early endosomes. After sorted at early endosomes, the complexes are further transported to lysosome and degraded. Conjugation of ubiquitin to the receptors serves as a sorting signal for transport to lysosomes. In this study, we examined the role of the deubiquitinating enzyme UBPY and ALG2 in regulation of growth factor receptor sorting at endosomes, and the following results were obtained.(1)Overexpression of UBPY reduced the ubiquitination level of EGF receptor (EGFR), and delayed its degradation in EGF-stimulated cells. Overexpression of Hrs caused the accumulation of endogenous UBPY on exaggerated endosomes. A catalytically inactive UBPY mutant clearly localized on endosomes, where it overlapped with EGFR when cells were stimulated with EGF. Depletion of endogenous UBPY by RNA interference resulted in elevated ubiquitination and accelerated degradation of EGF-activated EGFR. These results suggest that UBPY negatively regulates the rate of EGFR degradation by deubiquitinating EGFR on endosomes.(2)At endosomes, ligand-activated receptors are incorporated into luminal vesicles of endosomes that bud inward from its limiting membrane. Endosomes that contain such luminal vesicles are called the multivesicular body (MVB). We examined the role of ALG2 in the formation of the luminal vesicles. Depletion of endogenous ALG2 by RNA interference resulted in the reduction of the level of phospholipid LBPA, which is specifically localized to the membrane of the luminal vesicles. This reduction was also observed by an electron microscopy analysis. These results suggest thatALG2 plays an important role in the formation of the luminal vesicles in MVB.

当生长因子与其细胞表面受体结合时，生长因子/受体复合物被内化并转运至早期内体。在早期内体分选后，复合物进一步转运至溶酶体并降解。泛素与受体的结合作为转运至溶酶体的分选信号。在本研究中，我们检测了去泛素化酶UBPY和ALG2在调节内体生长因子受体分选中的作用，得到了以下结果。（1）UBPY的过度表达降低了EGF受体（EGFR）的泛素化水平，并且延缓其在 EGF 刺激细胞中的降解。 Hrs 的过度表达导致内源性 UBPY 在过量的内涵体上积累。催化失活的 UBPY 突变体明显定位在内体上，当细胞受到 EGF 刺激时，它与 EGFR 重叠。 RNA 干扰消除内源性 UBPY 导致泛素化升高并加速 EGF 激活的 EGFR 降解。这些结果表明UBPY通过使内涵体上的EGFR去泛素化来负向调节EGFR降解速率。(2)在内体中，配体激活的受体被整合到从其限制膜向内出芽的内涵体的管腔囊泡中。含有这种管腔囊泡的内体被称为多囊泡体（MVB）。我们研究了 ALG2 在管腔囊泡形成中的作用。通过 RNA 干扰消除内源性 ALG2 导致磷脂 LBPA 水平降低，磷脂 LBPA 专门位于管腔囊泡的膜上。通过电子显微镜分析也观察到这种减少。这些结果表明ALG2在MVB中管腔囊泡的形成中发挥重要作用。

项目成果

期刊论文数量（0）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Enhanced JNK activation by NESK without kinase activity upon caspase-mediated cleavage during apoptosis

DOI：
10.1016/j.cellsig.2005.03.004
发表时间：
2005-11-01
期刊：
CELLULAR SIGNALLING
影响因子：
4.8
作者：
Kakinuma, H;Inomata, H;Kitamura, N
通讯作者：
Kitamura, N

Regulation of EGF receptor downregulation by UBPY-mediated deubiquitination at endosomes

UBPY 介导的内体去泛素化调节 EGF 受体下调

DOI：
发表时间：
2005
期刊：
Mol.Biol.Cell 16
影响因子：
0
作者：
Moriyama-Kita M;et al.;佐藤博;E. Shirako;A. Kondo;E. Mizuno;M.Nakamura;E.Mizuno;M.Maemura;A.Yamasaki;M.Nakamura;M.Komada;H.Kakinuma;H.Tanaka;J.Han;E.Mizuno
通讯作者：
E.Mizuno

A deubiquitinating enzyme UB`Y regulates the level of protein ubiquitination on endosomes

去泛素化酶 UB`Y 调节内体上蛋白质泛素化的水平

DOI：
发表时间：
2006
期刊：
Traffic 7
影响因子：
0
作者：
M.Nakamura;E.Mizuno;A.Yamasaki;M.Nakamura et al.;E.Mizuno et al.;A.Yamasaki et al.;M.Nakamura;E.Mizuno
通讯作者：
E.Mizuno

A deubiquitinating enzyme UBPY regulates the level of protein ubiquitination on endosomes