Glutamate receptor activation evokes calpain-mediated degradation of Sp3 and Sp4, the prominent Sp-family transcription factors in neurons
Glutamate receptor activation evokes calpain-mediated degradation of Sp3 and Sp4, the prominent Sp-family transcription factors in neurons
复制标题
DOI：
10.1111/j.1471-4159.2006.04297.x
复制
发表时间：
2007-03-01
影响因子：
4.7
通讯作者：
Barger, Steven W.
中科院分区：
文献类型：
--
作者：
Mao, Xianrong;Yang, Shao-Hua;Barger, Steven W.
Sp 家族转录因子（Sp1、Sp3 和 Sp4）包含一个锌指结构域，可与富含 G-C/T 的 DNA 序列结合。通过 mRNA 的 RT-PCR 分析、蛋白质印迹分析、免疫荧光和 DNA 结合测定的抗体依赖性“超移”进行测定，大脑神经元中重要的 Sp 家族因子被鉴定为 Sp3 和 Sp4。相比之下，神经胶质细胞被发现表达 Sp1 和 Sp3。我们之前表明，Sp 家族因子的 G-C/T 结合活性模式会因谷氨酸受体激活所伴随的钙流入而快速而特异性地改变。在这里，我们证明 Sp 因子活性在体内脑缺血/再灌注损伤后也会丧失。与其钙依赖性性质一致，我们发现谷氨酸对 Sp 家族因子的作用可以被钙蛋白酶（钙激活的中性半胱氨酸蛋白酶）抑制剂阻断。纯化的钙蛋白酶 I 将 Sp3 和 Sp4 裂解成保留 G-C/T 结合活性的产物，这与在谷氨酸处理的神经元中观察到的物种一致。这些数据提供了谷氨酸受体激活对与基因表达相关的分子事件影响的详细信息。
Sp-family transcription factors (Sp1, Sp3 and Sp4) contain a zinc-finger domain that binds to DNA sequences rich in G-C/T. As assayed by RT-PCR analysis of mRNA, western-blot analysis, immunofluorescence, and antibody-dependent "supershift" of DNA-binding assays, the prominent Sp-family factors in cerebral neurons were identified as Sp3 and Sp4. By contrast, glial cells were found to express Sp1 and Sp3. We previously showed that the pattern of G-C/T binding activity of Sp-family factors is rapidly and specifically altered by the calcium influx accompanying activation of glutamate receptors. Here, we demonstrate that Sp-factor activity is also lost after a cerebral ischemia/reperfusion injury in vivo. Consistent with its calcium-dependent nature, we found that glutamate's effect on Sp-family factors could be blocked by inhibitors of calpains, neutral cysteine proteases activated by calcium. Purified calpain I cleaved Sp3 and Sp4 into products that retained G-C/T-binding activity, consistent with species observed in glutamate-treated neurons. These data provide details of an impact of glutamate-receptor activation on molecular events connected to gene expression.