Department of Biochemistry, Molecular Neuroscience Center and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
J Neurosci. 2010 Oct 27;30(43):14366-70. doi: 10.1523/JNEUROSCI.3899-10.2010.
Precise regulation of cyclin-dependent kinase 5 (Cdk5), a member of the cyclin-dependent kinase family, is critical for proper neuronal development and functions. Cdk5 is activated through its association with the neuron-specific activator p35 or p39. Nonetheless, how its kinase activity is regulated in neurons is not well understood. In this study, we found that Cdk5 activity is regulated by S-nitrosylation, a post-translational modification of protein that affects a plethora of neuronal functions. S-nitrosylation of Cdk5 occurs at Cys83, which is one of the critical amino acids within the ATP-binding pocket of the kinase. Upon S-nitrosylation, Cdk5 exhibits reduced kinase activity, whereas mutation of Cys83 to Ala on Cdk5 renders the kinase refractory to such inhibition. Importantly, S-nitrosylated Cdk5 can be detected in the mouse brain, and blocking the S-nitrosylation of Cdk5 in cultured hippocampal neurons enhances dendritic growth and branching. Together, our findings reveal an important role of S-nitrosylation in regulating Cdk5 kinase activity and dendrite growth in neurons during development.
精确调节细胞周期蛋白依赖性激酶 5（Cdk5），细胞周期蛋白依赖性激酶家族的一员，对神经元的正常发育和功能至关重要。Cdk5 通过与神经元特异性激活剂 p35 或 p39 的结合而被激活。然而，其激酶活性在神经元中的调节机制尚不清楚。在这项研究中，我们发现 Cdk5 的活性受到 S-亚硝基化的调节，这是一种影响多种神经元功能的蛋白质翻译后修饰。Cdk5 的 S-亚硝基化发生在 Cys83，这是激酶的 ATP 结合口袋内的关键氨基酸之一。Cdk5 发生 S-亚硝基化后，激酶活性降低，而将 Cdk5 的 Cys83 突变为丙氨酸则使激酶对这种抑制作用产生抗性。重要的是，在小鼠大脑中可以检测到 S-亚硝基化的 Cdk5，并且在培养的海马神经元中阻断 Cdk5 的 S-亚硝基化可增强树突的生长和分支。总之，我们的研究结果揭示了 S-亚硝基化在调节发育过程中神经元中 Cdk5 激酶活性和树突生长中的重要作用。
