Functional Regulation of Erb B family by N-glycosylation

N-糖基化对 Erb B 家族的功能调节

基本信息

批准号：
18590272
负责人：
TAKAHASHI Motoko
金额：
$ 2.11万
依托单位：
Sapporo Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18590272/
关键词：
N-glycan glycosylation ErbB EGFR dimerization adenylyl cyclase 糖鎖増殖因子受容体 ErbB2 ErbB3 二量体形成

项目摘要

Glycosylation is one of the most common post-translational modification, and is known to change physico-chemical properties of proteins. In this study, I examine the function of N-glycan of ErbB family and adenylyl cyclase.ErbB3 has 10 potential glycosylation sites in its extracellular domain. A series of human ErbB3 molecules devoid of N-glycan were prepared and transfected to Flp-In-CHO cells for stable expression. It was revealed that the Asn 418 to Gln mutant (N418Q) mutant of ErbB3 underwent ligand-independent homodimerization. When overexpressed with ErbB2, ligand-independent hetero-dimerization was observed and Erk and Akt phosphorylation was upregulated in the absence of of ErbB3 coexpressed with ErbB2 promoted cell proliferation and colony formation in soft agar in an Erk and Akt-dependent manner. The N418Q mutation also promoted the growth of tumors in athymic mice when injected subcutaneously. Thus, Asn 418-linked N-glycan in ErbB3 plays an essential role in regulating receptor heterodimerization with ErbB2 and might have an effect on transforming activity.Adenylyl cyclase III (ACIII) has 2 potential glycosylation sites in its extracellular domain, and it was suggested that glycosylation is involved in its enzymatic activity. When processing of glycosylation was suppressed by introducing GnT-III, one of glycosyltransferases, forskolin-induced ACIII activation and downstream signaling such as the synthesis of cAMP and the phosphorylation of CREB were significantly upregulated. Now the mechanisms of the regulation of ACIII by the structure of N-glycan is being investigated.

糖基化是最常见的翻译后修饰之一，已知会改变蛋白质的物理化学特性。在这项研究中，我检查了ERBB家族和腺苷酸环化酶的N-聚糖的功能。ERBB3在其细胞外结构域中具有10个潜在的糖基化位点。制备一系列没有N-聚糖的人Erbb3分子，并将其转染至flp-in-Cho细胞以稳定表达。据表明，ERBB3的ASN 418至GLN突变体（N418Q）突变体进行了非配体均依赖性均二聚化。当用ERBB2过表达时，观察到与配体无关的异差分化化，并且在没有ERBB3与ERBB2共表达ERBB3的情况下，ERK和AKT磷酸化被上调，促进了ERK和AKT依赖性依赖性依赖性的ERBB3的细胞增殖和菌落形成。当皮下注射时，N418Q突变还促进了无胸腺小鼠的肿瘤生长。因此，ERBB3中的ASN 418连接的N-聚糖在调节ERBB2的受体异二聚体中起着至关重要的作用，并且可能对转化活性具有影响。AdenyllylCycclase III（ACIII）具有2个潜在的糖基化位点，其外细胞域中的活性涉及糖基化的活性。当引入GNT-III抑制糖基化的加工时，GNT-III（糖基转移酶之一），Forskolin诱导的ACIII激活和下游信号传导（例如CAMP的合成和CREB的磷酸化）被显着上调。现在，正在研究通过N-聚糖结构调节ACIII的机制。