Regulation of growth factor receptor downregulation by a deubiquitinating enzyme UBPY

去泛素化酶 UBPY 对生长因子受体下调的调节

基本信息

批准号：
17570156
负责人：
KOMADA Masayuki
金额：
$ 2.24万
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 (C)
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

项目摘要

1.Regulation of the epidermal growth factor (EGF) receptor downregulation by a deubiquitinating enzyme UBPYUbiquitination of ligand-activated EGF receptor serves as a signal that targets the protein for lysosomal trafficking. We found that UBPY deubiquitinates activated EGF receptor on early endosomes and delays its downregulation. These results indicated that by removing the "lysosome-targeting signal" from the receptor and inhibiting its trafficking to lysosomes, UBPY regulates the downregulation of EGF receptor negatively.2.Regulation of the morphology of early endosomes by a deubiquitinating enzyme UBPYInhibition of the UBPY function by expressing a dominant-negative mutant or siRNA resulted in the accumulation of ubiquitinated proteins on early endosomes and the morphological aberration of the organelle. Electromicroscopic study showed that early endosomes are aberrantly aggregated in UBPY-inhibited cells. These results suggested that the regulation of the level of protein ubiquit … More ination on early endosomes by UBPY is essential for maintaining the morphology of the organelle.3.Regulation of the deubiquitinating activity of UBPY by 14-3-3 proteins in the M phaseWe found that UBPY binds 14-3-3 proteins via a consensus 14-3-3-binding motif, RSYS^<680>SP. The binding required the phosphorylation of S^<680>. We also found that the binding of 14-3-3 inhibits the catalytic activity of UBPY. Finally, UBPY is dephosphorylated, dissociated from 14-3-3 proteins, and catalytically activated in the M phase, suggesting that elevated activity of UBPY regulates the functions of early endosomes in the M phase.4.Mechanism of the localization of a deubiquitinating enzyme AMSH to early endosomesWe found that AMSH and its homolog AMSH-like protein (AMSH-LP) bind to the terminal domain of clathrin heavy chain via a novel ~30-amino-acid clathrin-binding motif which is conserved between AMSH and AMSH-LP. Deletion of the clathrin-binding motif from these deubiquitinating enzymes, as well as siRNA-mediated knockdown of cellular clathrin, led to their mislocalization to the cytoplasm. These results suggested that AMSH and AMSH-LP are anchored to early endosomes through the interaction with the clathrin coat on the endosomal membrane. Less

1.通过将配体激活的EGF受体的去泛素化酶泛素化酶的酶泛素化酶的调节是靶向蛋白质的蛋白质，用于溶酶体运输。我们发现，乌布皮去素化素在早期内体上激活的EGF受体，并延迟其下调。 These results indicated that by removing the "lysosome-targeting signal" from the receptor and inhibiting its Trafficking to lysosomes, UBPY regulates the downregulation of EGF receptor negatively.2.Regulation of the morphology of early endosomes by a deubiquitinating enzyme UBPYInhibition of the UBPY function by expressing a dominant-negative mutant or siRNA resulted in the accumulation在早期内体上的泛素化蛋白和细胞器的形态像差。静电性研究表明，早期内体被异常聚集在ubpy抑制的细胞中。这些结果表明，对蛋白质泛素水平的调节……ubpy对早期内体的更多介入对于维持细胞器的形态至关重要。 rsys^<680> sp。结合需要S^<680>的磷酸化。我们还发现，14-3-3的结合抑制了Ubpy的催化活性。 Finally, UBPY is dephosphorylated, dissociated from 14-3-3 proteins, and catalytically activated in the M phase, suggesting that elevated activity of UBPY regulates the functions of early endosomes in the M phase.4.Mechanism of the localization of a deubiquitinating enzyme AMSH to early endosomesWe found that AMSH and its homolog AMSH-like protein (AMSH-LP) bind to the网格蛋白重链的末端结构域通过新颖的〜30氨基酸酸环蛋白结合基序，该基序是在AMSH和AMSH-LP之间配置的。从这些去泛素化酶以及siRNA介导的细胞网蛋白的敲低的脱氧蛋白结合基序的删除导致其对细胞质的错误定位。这些结果表明，通过与内体膜上的网格蛋白涂层的相互作用，AMSH和AMSH-LP锚定在早期内体上。较少的