Molecular and cellular biological study about the abnormal neurite outgrowth and protein phosphorylation in temporal lobe epilepsy

颞叶癫痫的一个形态学特征是海马齿状颗粒细胞的异常突起。Ca^<2+>/钙调素依赖性蛋白激酶II （CaM激酶II）的某些亚型可能与这种异常的神经突生长有关。在CaM激酶II中，已从脑中鉴定出四个亚基和几个同工型。为了探讨CaM激酶II各亚型在颞叶癫痫中的病理生理作用，我们主要研究了CaM激酶II的δ亚基（CaM kinase IIdelta）的结构和功能。1)制备了抗CaM激酶IIdelta抗体，并检测了该亚基在脑中的定位。2)从大鼠脑中获得了6个CaM激酶IIdelta亚型的cdna。在这些亚型中，delta3在转染的ng108 -15细胞中定位于细胞核中。3) ng108 - 15细胞过表达delta3可诱导脑源性神经营养因子（BDNF）基因表达，促进脑内特定神经元群体的存活和分化。4)我们发现CaM kinase II在PC12细胞和NG108-15细胞中的主要亚型是delta2。δ 2似乎主要分布在高尔基体中。5) NG 108-15细胞的其他同工异构体定位于细胞质中。因此，这些异构体可能通过细胞骨架蛋白（如微管相关蛋白2）的磷酸化参与神经突生长的调节。这些结果表明，每种亚型都定位于神经元的特定部位，在神经元功能中发挥重要作用。

A morphological characteristic of temporal lobe epilepsy consists of the abnormal neurite outgrowth of the hippocampal dentate granule cells. Some isoforms of Ca^<2+>/calmodulin-dependent protein kinase II (CaM kinase II) may be related to this abnormal neurite outgrowth. Among CaM kinase II, four subunits and several isoforms have been identified from brain. In order to investigate the pathophysiological roles of each isoform of CaM kinase II in temporal lobe epilepsy, we studied about the structures and functions of CaM kinase II isoforms mainly about the delta subunit of CaM kinase II (CaM kinase IIdelta). 1) We prepared the antibody against CaM kinase IIdelta and examined the localization of the subunit in brain. 2) We obtained the cDNAs of 6 isoforms of CaM kinase IIdelta from rat brain. Among these isoforms, delta3 was localized in the nuclei in transfected NG1O8-15 cells. 3) Overexpression of delta3 in NG1O8- 15 cells induced the gene expression of brain-derived neurotrophic factor (BDNF) which promotes survival and differentiation of specific populations of neurons in the brain. 4) We found that the major isoform of CaM kinase II in PC12 cells and NG108-15 cells was delta2. And delta2 appeared to be mainly localized in Golgi's apparatus.5) Other isoforms were localized in the cytoplasm in NG 108-15 cells. Therefore, these isoforms may be involved in the regulation of neurite outgrowth via phosphorylation of cytoskeletal proteins such as microtubule-associated protein 2.These results suggest that each isoform is localized in the specific site in neurons to play some important roles in neuronal functions.