The PTP, STEP, Regulates Amphetamine Actions

PTP、STEP 规范安非他明行为

• 批准号: 7059433
• 负责人: Paul J Lombroso
• 金额: $ 31.93万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-15 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7059433
• 关键词: JUN kinase; amphetamines; amygdala; behavioral /social science research tag; behavioral habituation /sensitization; biological signal transduction; corpus striatum; dopamine; fos protein; frontal lobe /cortex; gene expression; genetic regulation; genetically modified animals; glutamates; immunocytochemistry; laboratory mouse; laboratory rabbit; laboratory rat; mitogen activated protein kinase; nucleus accumbens; phosphorylation; protein binding; protein tyrosine phosphatase; western blottings

DESCRIPTION (provided by applicant): Chronic intermittent exposure to stimulant drugs produces persistent and progressive changes in behavior including responses to subsequent drug challenges. This phenomenon is termed sensitization. Although animal models have provided information with regard to the initial biochemical changes involved in sensitazation, less is known about subsequent steps. The present RO1 will investigate this question. Our laboratory has discovered a family of protein tyrosine phosphatases (PTPs) that are expressed within neurons of the CNS. This PTP, termed STEP, is highly enriched in the striatum, nucleus accumbens, amygdala, and the frontal cortices. We recently determined that STEP regulates the activity of the MAP kinase members, ERKI/2. STEP is itself regulated by dopamine and glutamate signaling. Dopamine stimulation leads to the phosphorylation of key regulatory residues and inactivates STEP. Glutamate signaling dephosphorylates and activates STEP. STEP thus acts as a switch that regulates the activity ERK1/2 and limits its ability to activate downstream substrates. We propose that STEP regulates the effects of amphetamine. It does so by controlling the activity of ERKI/2. Consistent with this hypothesis, preliminary data in rats demonstrate that STEP is phosphorylated after amphetamine treatment. The sites phosphorylated are key regulatory residues in a domain required for binding to the ERKs. When STEP is phosphorylated at that site, the ERK signaling cascade is sustained. We will conduct time-course and dose-response analyses with psychostimulants, and perform immunocytochemical and Western blot analyses to determine the patterns of p-ERK, p-STEP, p-CREB, p- Elk-1 and the immediate early genes c-fos, jun and AfosB. We propose that the duration that ERKI/2 remain active determines the pattern of gene expression. Functional studies will disrupt the ability of STEP binding to ERK or disrupt the ability of STEP to let go of ERK. This will be tested by using TAT-peptide technology that introduces protein sequences that either prevent STEP from binding to ERK or never let go of ERK. We show preliminary feasibility data on this approach. A complementary set of experiments will study the STEP knock-out mouse that we predict is hypersensitive to stimulant treatment.

描述(由申请人提供)：慢性间歇性接触兴奋剂药物会导致行为的持续性和渐进性变化，包括对随后的药物挑战的反应。这种现象称为敏化。虽然动物模型已经提供了与耸人听闻有关的最初生化变化的信息，但对随后的步骤知之甚少。 目前的RO1将调查这个问题。我们实验室发现了一类在中枢神经系统神经元中表达的蛋白酪氨酸磷酸酶(PTPs)家族。这种被称为STEP的PTP在纹状体、伏隔核、杏仁核和额叶皮质中高度丰富。我们最近确定了STEP调节MAP激酶成员Erki/2的活性。STEP本身受多巴胺和谷氨酸信号的调节。多巴胺刺激导致关键调控残基的磷酸化，并使STEP失活。谷氨酸信号转导去磷酸化并激活STEP。因此，STEP作为一个开关来调节ERK1/2的活性，并限制其激活下游底物的能力。 我们建议该步骤调节安非他明的作用。它通过控制Erki/2的活性来实现这一点。与这一假设一致，在大鼠身上的初步数据表明，在苯丙胺处理后，STEP被磷酸化。磷酸化的位点是与ERK结合所需结构域中的关键调控残基。当STEP在该位置被磷酸化时，ERK信号级联被维持。我们将对精神刺激剂进行时程和剂量-反应分析，并进行免疫细胞化学和蛋白质印迹分析，以确定p-ERK、p-STEP、p-CREB、p-ELK-1和即刻早期基因c-fos、jun和AfosB的模式。我们认为Erki/2保持活跃的持续时间决定了基因表达的模式。功能研究将破坏STEP与ERK结合的能力或STEP释放ERK的能力。这将通过使用TAT-多肽技术进行测试，该技术引入的蛋白质序列要么阻止STEP与ERK结合，要么永远不放过ERK。我们展示了这种方法的初步可行性数据。一组补充的实验将研究我们预测对刺激治疗敏感的步进式基因敲除小鼠。