Cyclin-dependent kinase 5 activators p35 and p39 facilitate formation of functional synapses
Cyclin-dependent kinase 5 activators p35 and p39 facilitate formation of functional synapses
复制标题
DOI：
10.1016/j.molbrainres.2005.04.014
复制
发表时间：
2005-08-18
期刊：
影响因子：
--
通讯作者：
Bark, C
中科院分区：
文献类型：
--
作者：
Johansson, JU;Lilja, L;Bark, C
细胞周期蛋白依赖性激酶5(CDK5)是突起生长过程中细胞信号的关键协调者。CDK5需要与调节蛋白P35或P39中的一个结合才能成为活性酶。为了研究CDK5是否在功能性突触的建立中起作用，我们在神经母细胞瘤-胶质瘤细胞系NG 108-15中检测了CDK5、p35和P39的表达，并记录了突触前过表达的CDK5、p35和P39在肌管中的突触后活动。内源CDK5和p35蛋白水平随着细胞分化的增加而增加，并优先分布到可溶性库中，而P39蛋白水平保持较低水平，主要存在于膜和细胞骨架部分。在NG108-15细胞中瞬时转导显性-负性CDK5突变体，然后在分化的肌肉细胞上培养，通过突触后微小终板电位(MEPPs)测量，突触活性显著降低。CDK5/p35或CDK5/P39的过表达导致突触后活动的突触结构和MEPP频率显著增加。这些结果表明，CDK5、P35和P39在NG108-15细胞中内源性表达，并表现出明显的亚细胞定位，并且CDK5/P35和CDK5/P39都是功能性突触形成的中心。(C)2005 Elsevier B.V.保留所有权利。
Cyclin-dependent kinase 5 (Cdk5) has emerged as a key coordinator of cell signaling in neurite outgrowth. Cdk5 needs to associate with one of the regulatory proteins p35 or p39 to be an active enzyme. To investigate if Cdk5 plays a role in the establishment of functional synapses, we have characterized the expression of Cdk5, p35, and p39 in the neuroblastoma-glioma cell line NG 108-15, and recorded postsynaptic activity in myotubes in response to presynaptic overexpression of Cdk5, p35, and p39. Endogenous Cdk5 and p35 protein levels increased with cellular differentiation and preferentially distributed to soluble pools, whereas the level of p39 protein remained low and primarily was present in membrane and cytoskeletal fractions. Transient transfection of a dominant-negative mutant of Cdk5 in NG108-15 cells and subsequent culturing on differentiating muscle cells resulted in a significant reduction in synaptic activity, as measured by postsynaptic miniature endplate potentials (mEPPs). Overexpression of either Cdk5/p35 or Cdk5/p39 resulted in a substantial increase in synaptic structures that displayed postsynaptic activities, as well as mEPP frequency. These findings demonstrate that Cdk5, p35, and p39 are endogenously expressed in NG108-15 cells, exhibit distinct subcellular localizations, and that both Cdk5/p35 and Cdk5/p39 are central in formation of functional synapses. (c) 2005 Elsevier B.V. All rights reserved.