Department of Neurobiology, Institute of Neuroscience, Zhejiang University School of Medicine, 388 Yu Hang-tang Road, Hangzhou, Zhejiang 310058, China.
Neurochem Int. 2010 Jul;56(8):962-70. doi: 10.1016/j.neuint.2010.04.006. Epub 2010 Apr 18.
Trafficking of AMPA receptors to and from synapses and their final localizations are critical for the expression of synaptic plasticity, which is regarded as the cellular basis of learning and memory. Protein that interacts with C Kinase 1 (PICK1), is one of the scaffolding proteins that interacts with AMPA receptors and regulates their trafficking in synaptic plasticity. In this study, we found that PICK1 could be a threonine-phosphorylated protein and identified threonine 82 (T82) in the PDZ domain of PICK1 as a potential phosphorylation site based on sequence and structural modeling analysis. We further performed co-immunoprecipitation experiments to confirm that T82 was indeed critical for the interaction between PICK1 and GluR2. In addition, T82E mutation mimicking the phosphorylation of PICK1 dispersed the colocalization of PICK1 and GluR2 in heterologous cells. Finally, the phosphorylated analog, T82E, inhibited PICK1's effect in regulating surface distribution of GluR2 and current mediated by GluR2. In summary, our data suggest that T82 is a potential phosphorylation site of PICK1 and is critical for the interaction of PICK1 with AMPA receptors and PICK1-regulated AMPA receptor localization.
AMPA 受体在突触前后的转运及其最终定位对于突触可塑性的表达至关重要，而突触可塑性被认为是学习和记忆的细胞基础。蛋白与 C 激酶 1（PICK1）相互作用，是与 AMPA 受体相互作用并调节其在突触可塑性中转运的支架蛋白之一。在本研究中，我们发现 PICK1 可以是一种苏氨酸磷酸化蛋白，并基于序列和结构建模分析，确定 PICK1 PDZ 结构域中的苏氨酸 82（T82）为潜在的磷酸化位点。我们进一步进行了共免疫沉淀实验，以确认 T82 对于 PICK1 和 GluR2 之间的相互作用确实至关重要。此外，模拟 PICK1 磷酸化的 T82E 突变会使 PICK1 和 GluR2 的共定位在异源细胞中分散。最后，磷酸化类似物 T82E 抑制了 PICK1 调节 GluR2 表面分布和 GluR2 介导的电流的作用。总之，我们的数据表明 T82 是 PICK1 的一个潜在磷酸化位点，对于 PICK1 与 AMPA 受体的相互作用以及 PICK1 调节的 AMPA 受体定位至关重要。
