β1,4-N-Acetylglucosaminyltransferase III down-regulates neurite outgrowth induced by costimulation of epidermal growth factor and integrins through the Ras/ERK signaling pathway in PC12 cells
β1,4-N-Acetylglucosaminyltransferase III down-regulates neurite outgrowth induced by costimulation of epidermal growth factor and integrins through the Ras/ERK signaling pathway in PC12 cells
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DOI：
10.1093/glycob/cwh016
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发表时间：
2004-02-01
期刊：
影响因子：
4.3
通讯作者：
Taniguchi, N
中科院分区：
文献类型：
--
作者：
Gu, JG;Zhao, YY;Taniguchi, N
大鼠嗜铬细胞瘤细胞系（PC 12），当转染β 1，4-N-乙酰葡糖胺转移酶III（GnT-III），催化形成一个平分的GlcNAc结构的N-聚糖，导致抑制神经突起生长诱导的表皮生长因子（EGF）和整合素的共刺激。轴突生长恢复的组成性激活的丝裂原或细胞外信号调节激酶激酶-1（MEK-1）的过度表达。与此一致，EGF受体（EGFR）介导的ERK激活在GnT-III转染子中被阻断。相反，显性阴性MEK-1的过表达或用MEK-1的特异性抑制剂PD 98059处理抑制了用模拟物转染的对照中的神经突生长。此外，GnT-III活性是这些抑制所必需的，因为显性负性GnT-III突变体（D321 A）的过表达未能减少神经突生长和EGFR介导的ERK激活。凝集素印迹分析证实，来自野生型GnT-III转染子的EGFR已通过在其N-聚糖结构中平分GlcNAc而被修饰。这种修饰导致EGF结合和EGFR自磷酸化显著减少。总的来说，这些结果构成了一个全面的证据，清楚地表明，GnT-III的过表达防止通过Ras/MAPK活化途径的EGF和整合素的共刺激诱导的神经突生长，并表明GnT-III可能是神经组织中细胞分化的重要调节剂。
A rat pheochromocytoma cell line (PC12), when transfected with beta1,4-N-acetylglucosaminyltransferase III (GnT-III), which catalyzes the formation of a bisecting GlcNAc structure in N-glycans, resulted in the suppression of neurite outgrowth induced by costimulation of epidermal growth factor (EGF) and integrins. The neurite outgrowth was restored by the overexpression of a constitutively activated mitogen- or extracellular signal-regulated kinase kinase-1 (MEK-1). Consistent with this, the EGF receptor (EGFR)-mediated ERK activation was blocked in GnT-III transfectants. Conversely, the overexpression of dominant negative MEK-1 or treatment with PD98059, a specific inhibitor of MEK-1, inhibited neurite outgrowth in controls transfected with mock. Furthermore GnT-III activity is required for these inhibitions, because the overexpression of a dominant negative GnT-III mutant (D321A) failed to reduce neurite outgrowth and EGFR-mediated ERK activation. Lectin blot analysis confirmed that EGFR from wild-type GnT-III transfectants had been modified by bisecting GlcNAc in its N-glycan structures. This modification led to a significant decrease in EGF binding and EGFR autophosphorylation. Collectively, the results constitute a comprehensive body of evidence to show clearly that the overexpression of GnT-III prevents neurite outgrowth induced by costimulation of EGF and integrins through the Ras/MAPK activation pathway and indicates that GnT-III may be an important regulator for cell differentiation in neural tissues.