Koh Cheng-Gee
School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
Neurosignals. 2006;15(5):228-37. doi: 10.1159/000101527. Epub 2007 Apr 4.
Neurons are specialized cell types which send out processes in order to communicate with other cells, which can be immediate neighbors or whose cell bodies are far distant. Neuronal morphology as in all cells is determined in large part through the regulation of the cytoskeleton. One of the key regulators of the actin cytoskeleton is the Rho family of GTPases. The Rho GTPases function as molecular switches to turn on or off downstream biochemical pathways depending on the stimuli. Their activities and their regulation are controlled by many other proteins such as the guanine nucleotide exchange factors and the GTPase-activating proteins. The activities of some of the Rho family members are reported to be antagonistic to one another. In general, Rac and Cdc42 promote neurite outgrowth while RhoA stimulates retraction. The balance of these opposing activities of the different Rho GTPases is crucial for the morphology and function of the neurons.
神经元是一种特殊的细胞类型，它们发出突起以便与其他细胞进行通讯，这些其他细胞可以是紧邻的细胞，也可以是细胞体距离很远的细胞。与所有细胞一样，神经元的形态在很大程度上是通过细胞骨架的调节来决定的。肌动蛋白细胞骨架的关键调节因子之一是Rho家族的GTP酶。Rho GTP酶作为分子开关，根据刺激开启或关闭下游生化途径。它们的活性及其调节由许多其他蛋白质控制，如鸟嘌呤核苷酸交换因子和GTP酶激活蛋白。据报道，一些Rho家族成员的活性相互拮抗。一般来说，Rac和Cdc42促进神经突生长，而RhoA刺激神经突回缩。不同Rho GTP酶这些相反活性的平衡对于神经元的形态和功能至关重要。
