Inactivation of integrin-linked kinase induces aberrant tau phosphorylation via sustained activation of glycogen synthase kinase 3β in N1E-115 neuroblastoma cells
Inactivation of integrin-linked kinase induces aberrant tau phosphorylation via sustained activation of glycogen synthase kinase 3β in N1E-115 neuroblastoma cells
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DOI：
10.1074/jbc.m304113200
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发表时间：
2003-07-18
影响因子：
4.8
通讯作者：
Nishimura, M
中科院分区：
文献类型：
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作者：
Ishii, T;Furuoka, H;Nishimura, M
整合素连接激酶（ILK）是一种粘着斑丝氨酸/苏氨酸蛋白激酶，在整合素和生长因子信号通路中具有重要作用。最近，我们证明ILK在N1 E-115神经母细胞瘤细胞中表达，并控制在层粘连蛋白上生长的血清饥饿细胞中的整联蛋白依赖性神经突生长（石井，T.，Satoh，E.，和Nishimura，M.（2001）J.Biol.Chem.276，42994 - 43003）。在这里，我们报告，ILK控制tau蛋白磷酸化通过调节糖原合成酶激酶-3 β（GSK-3 β）的活性在N1 E-115细胞。激酶缺陷型ILK突变体（DN-ILK）的稳定转染导致N1 E-115细胞中Tau-1抗体识别位点处的异常tau磷酸化，所述位点与阿尔茨海默病患者脑中成对螺旋丝PHF-tau中的一些磷酸化位点相同。表达DN-ILK的细胞中的tau磷酸化水平在正常和分化条件下是恒定的。另一方面，在亲本对照细胞中未观察到异常tau磷酸化。ILK失活导致GSK-3 β的活性形式增加，但非活性形式减少，GSK-3 β是参与PHF-tau形成的候选激酶。此外，用锂抑制GSK-3 β可防止DN-ILK表达细胞中异常的tau磷酸化。这些结果表明，ILK失活通过持续激活N1 E-115细胞中的GSK-3 β导致异常tau磷酸化。ILK直接磷酸化GSK-3 β并抑制其活性。因此，内源性ILK通过抑制N1 E-115细胞中的GSK-3 β活性来防止GSK-3 β诱导的异常tau磷酸化。
Integrin-linked kinase (ILK) is a focal adhesion serine/ threonine protein kinase with an important role in integrin and growth factor signaling pathways. Recently, we demonstrated that ILK is expressed in N1E-115 neuroblastoma cells and controls integrin-dependent neurite outgrowth in serum-starved cells grown on laminin (Ishii, T., Satoh, E., and Nishimura, M. ( 2001) J. Biol. Chem. 276, 42994 - 43003). Here we report that ILK controls tau phosphorylation via regulation of glycogen synthase kinase-3beta (GSK-3beta) activity in N1E-115 cells. Stable transfection of a kinase-deficient ILK mutant (DN-ILK) resulted in aberrant tau phosphorylation in N1E-115 cells at sites recognized by the Tau-1 antibody that are identical to some of the phosphorylation sites in paired helical filaments, PHF-tau, in brains of patients with Alzheimer's disease. The tau phosphorylation levels in the DN-ILK-expressing cells are constant under normal and differentiating conditions. On the other hand, aberrant tau phosphorylation was not observed in the parental control cells. ILK inactivation resulted in an increase in the active form but a decrease in the inactive form of GSK-3beta, which is a candidate kinase involved in PHF-tau formation. Moreover, inhibition of GSK-3beta with lithium prevented aberrant tau phosphorylation in the DN-ILK-expressing cells. These results suggest that ILK inactivation results in aberrant tau phosphorylation via sustained activation of GSK-3beta in N1E-115 Cells. ILK directly phosphorylates GSK-3beta and inhibits its activity. Therefore, endogenous ILK protects against GSK-3beta-induced aberrant tau phosphorylation via inhibition of GSK-3beta activity in N1E-115 cells.