Mutation of N-linked glycosylation at Asn548 in CD133 decreases its ability to promote hepatoma cell growth.
Mutation of N-linked glycosylation at Asn548 in CD133 decreases its ability to promote hepatoma cell growth.
复制标题
CD133中Asn548的N联糖基化突变降低了其促进肝癌细胞生长的能力
DOI：
10.18632/oncotarget.4115
复制
发表时间：
2015-08-21
期刊：
影响因子：
--
通讯作者：
Jiang J
中科院分区：
文献类型：
--
作者：
Liu Y;Ren S;Xie L;Cui C;Xing Y;Liu C;Cao B;Yang F;Li Y;Chen X;Wei Y;Lu H;Jiang J
膜糖蛋白CD133是一种受欢迎的肿瘤干细胞标记物，在许多肿瘤类型中对癌症的发生和侵袭起作用。CD133通过其磷酸化的Y828残基和PI3K调节亚基P85之间的相互作用以及与β-连环蛋白的相互作用促进肿瘤的发生。虽然CD133糖基化被认为与其功能有关，但N-糖基化对其功能的贡献仍不清楚。在这里，我们用质谱仪分析了CD133中N-糖基化的确切位置(S)，发现CD133的所有8个潜在的N-糖基化位点都可能被N-糖链占据。单个N-糖基化位点的缺失对CD133的表达水平或膜定位没有影响。然而，糖基化位点Asn548突变显著降低了CD133促进肝癌细胞生长的能力。此外，Asn548突变减少了CD133与β-连环蛋白的相互作用，并抑制了CD133过表达激活β-连环蛋白信号。我们的结果确定了CD133糖基化位点的特征和功能。这些数据可能有助于阐明糖基化对CD133的分子调控作用，并增强我们对糖基化CD133作为癌症治疗靶点的作用的理解。
The membrane glycoprotein CD133 is a popular marker for cancer stem cells and contributes to cancer initiation and invasion in a number of tumor types. CD133 promotes tumorigenesis partly through an interaction between its phosphorylated Y828 residue and the PI3K regulatory subunit p85, and the interaction with β-catenin. Although CD133 glycosylation is supposed to be associated with its function, the contribution of N-glycosylation to its functions remains unclear. Here we analyzed the exact site(s) of N-glycosylation in CD133 by mass spectrometry and found that all eight potential N-glycosylation sites of CD133 could be indeed occupied by N-glycans. Loss of individual N-glycosylation sites had no effect on the level of expression or membrane localization of CD133. However, mutation at glycosylation site Asn548 significantly decreased the ability of CD133 to promote hepatoma cell growth. Furthermore, mutation of Asn548 reduced the interaction between CD133 and β-catenin and inhibited the activation of β-catenin signaling by CD133 overexpression. Our results identified the characteristics and function of CD133 glycosylation sites. These data could potentially shed light on molecular regulation of CD133 by glycosylation and enhance our understanding of the utility of glycosylated CD133 as a target for cancer therapies.