The interaction of Munc 18 (p67) with the p10 domain of p35 protects in vivo Cdk5/p35 activity from inhibition by TFP5, a peptide derived from p35.
The interaction of Munc 18 (p67) with the p10 domain of p35 protects in vivo Cdk5/p35 activity from inhibition by TFP5, a peptide derived from p35.
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DOI：
10.1091/mbc.e15-12-0857
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发表时间：
2016-11-01
影响因子：
3.3
通讯作者：
Pant HC
中科院分区：
文献类型：
--
作者：
Amin ND;Zheng Y;Bk B;Shukla V;Skuntz S;Grant P;Steiner J;Bhaskar M;Pant HC
Cdk 5激酶调节蛋白（TFP 5）p35的截短片段特异性抑制过度活跃的Cdk 5/p25活性并挽救模型小鼠中的阿尔茨海默病和帕金森病表型。为了解释Cdk 5/p25活性的选择性抑制，p25中不存在的p35的p10 N-末端结构域使Cdk 5/p35不受影响。在一系列的研究中，我们已经确定了TFP 5，一个截短的片段的p35，Cdk 5激酶调节蛋白，它抑制Cdk 5/p35和过度活跃的Cdk 5/p25活动在试管实验中。然而，在皮质神经元中，以及在阿尔茨海默病（AD）模型小鼠体内，该肽特异性抑制Cdk 5/p25复合物，而不是内源性Cdk 5/p35。为了解释Cdk 5/p25活性的选择性抑制，我们提出p35的“p10”N-末端结构域在p25中不存在，因为p10结合大分子（例如，微管蛋白和肌动蛋白）作为膜结合的多聚体复合物，其有利于p35与Cdk 5结合和催化。为了验证这一假设，我们专注于Munc 18，一个关键的突触相关的神经元蛋白，与Cdk 5/p35在膜结合的多聚体复合物中的许多蛋白质之一。在这里，我们表明，在体外，加入p67保护Cdk 5/p35，并没有影响Cdk 5/p25的活性在TFP 5的存在。在用p67 siRNA转染的皮质神经元中，我们还表明TFP 5抑制Cdk 5/p35活性，而在p67存在下，活性受到保护。它这样做不影响细胞周期蛋白激酶的Cdk家族的任何其他激酶。这种差异可能具有显著的治疗价值，因为人类大脑中失调的、过度活跃的Cdk 5/p25复合物的积累与AD和其他神经退行性疾病的病理学有关。
A truncated fragment of p35, the Cdk5 kinase regulatory protein (TFP5), inhibits specifically hyperactive Cdk5/p25 activity and rescues the Alzheimer’s disease and Parkinson’s disease phenotype in model mice. To account for the selective inhibition of Cdk5/p25 activity, the p10 N-terminal domain of p35, absent in p25, spares Cdk5/p35. In a series of studies, we have identified TFP5, a truncated fragment of p35, the Cdk5 kinase regulatory protein, which inhibits Cdk5/p35 and the hyperactive Cdk5/p25 activities in test tube experiments. In cortical neurons, however, and in vivo in Alzheimer’s disease (AD) model mice, the peptide specifically inhibits the Cdk5/p25 complex and not the endogenous Cdk5/p35. To account for the selective inhibition of Cdk5/p25 activity, we propose that the “p10” N-terminal domain of p35, absent in p25, spares Cdk5/p35 because p10 binds to macromolecules (e.g., tubulin and actin) as a membrane-bound multimeric complex that favors p35 binding to Cdk5 and catalysis. To test this hypothesis, we focused on Munc 18, a key synapse-associated neuronal protein, one of many proteins copurifying with Cdk5/p35 in membrane-bound multimeric complexes. Here we show that, in vitro, the addition of p67 protects Cdk5/p35 and has no effect on Cdk5/p25 activity in the presence of TFP5. In cortical neurons transfected with p67siRNA, we also show that TFP5 inhibits Cdk5/p35 activity, whereas in the presence of p67 the activity is protected. It does so without affecting any other kinases of the Cdk family of cyclin kinases. This difference may be of significant therapeutic value because the accumulation of the deregulated, hyperactive Cdk5/p25 complex in human brains has been implicated in pathology of AD and other neurodegenerative disorders.