Tech: a RhoA GEF selectively expressed in hippocampal and cortical neurons
Tech: a RhoA GEF selectively expressed in hippocampal and cortical neurons
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DOI：
10.1111/j.1471-4159.2004.02930.x
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发表时间：
2005-02-01
影响因子：
4.7
通讯作者：
Baraban, JM
中科院分区：
文献类型：
--
作者：
Marx, R;Henderson, J;Baraban, JM
最近的研究表明小 G 蛋白 Rho 家族参与神经元形态的调节，重点关注识别神经元中 Rho 信号通路的关键组成部分。为此，我们进行了旨在确定 Tech 的定位和功能的研究，Tech 是一种在大脑中高度富集的 Rho 鸟嘌呤核苷酸交换因子 (GEF) 家族成员。我们发现 Tech 在皮质和海马神经元中选择性表达，在这些细胞的细胞体和树突中具有明显的 Tech 免疫染色。对主要 Rho 亚家族原型成员 RhoA、Rac1 和 Cdc42 的体外研究表明，Tech 选择性结合并激活 RhoA。为了评估Tech是否可能参与神经元形态的调节，我们检查了Tech构建体对原代培养物中生长的皮质神经元形态的影响。我们发现组成型活性技术构建体 Tech 245DeltaC 减少了这些神经元上存在的树突状突起的数量。这种减少似乎是由 RhoA 的激活介导的，因为它是通过在 Tech 的 DH 结构域中插入点突变而阻断的，这会阻止其激活 RhoA 的能力或显性失活 RhoA 构建体的共表达。随着 Tech 蛋白水平在产后发育过程中增加，并在成年期保持在峰值水平，这些结果表明 Tech 调节发育和成熟前脑神经元中的 RhoA 信号通路。
Recent studies implicating the Rho family of small G proteins in the regulation of neuronal morphology have focused attention on identifying key components of Rho signaling pathways in neurons. To this end, we have conducted studies aimed at defining the localization and function of Tech, a Rho guanine nucleotide exchange factor (GEF) family member that is highly enriched in brain. We have found that Tech is selectively expressed in cortical and hippocampal neurons with prominent Tech immunostaining apparent in the cell bodies and dendrites of these cells. In vitro studies with prototypical members of the major Rho subfamilies, RhoA, Rac1 and Cdc42, indicate that Tech binds selectively to and activates RhoA. To assess whether Tech may be involved in the regulation of neuronal morphology, we examined the effects of Tech constructs on the morphology of cortical neurons grown in primary culture. We found that a constitutively active Tech construct, Tech 245DeltaC, decreases the number of dendritic processes present on these neurons. This reduction appears to be mediated by activation of RhoA as it is blocked by insertion of a point mutation into the DH domain of Tech which blocks its ability to activate RhoA or coexpression of a dominant negative RhoA construct. As Tech protein levels increase during post-natal development and remain at peak levels into adulthood, these results indicate that Tech regulates RhoA signaling pathways in developing and mature forebrain neurons.