Regulation of synaptic strength and AMPA receptor subunit composition by PICK1.
Regulation of synaptic strength and AMPA receptor subunit composition by PICK1.
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DOI：
10.1523/jneurosci.4378-03.2004
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发表时间：
2004-06-09
期刊：
影响因子：
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通讯作者：
Isaac JT
中科院分区：
文献类型：
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作者：
Terashima A;Cotton L;Dev KK;Meyer G;Zaman S;Duprat F;Henley JM;Collingridge GL;Isaac JT
PICK1（与 C 激酶 1 相互作用的蛋白质）调节 AMPA 受体 (AMPAR) GluR2 亚基的表面表达，然而，这种相互作用的功能后果尚不清楚。先前的工作表明 PICK1 促进 AMPAR 的内化。然而，我们发现当 PICK1 在海马切片的 CA1 区域病毒表达时，它会导致 AMPAR 介导的 EPSC 振幅增加。这种效应与 AMPAR 整流的增加和对多胺毒素的敏感性有关。这些作用被 PKC 或钙/钙调蛋白依赖性蛋白激酶 II 抑制剂阻断，表明病毒表达的 PICK1 通过内源激酶级联发出信号。相比之下，在 N-乙基马来酰亚胺敏感因子位点阻断与 GluR2 的相互作用并不会引起亚基组成的变化，这表明 PICK1 的影响不仅仅是从表面去除 AMPAR 的非特异性结果。对分离培养的海马神经元的免疫细胞化学和生化分析表明，PICK1 导致内源性 GluR2 表面表达减少，但 GluR1 表面水平没有变化。为了解决 PICK1 的生理作用，我们病毒表达了 C 端 GluR2 肽。阻断内源性 PICK1 PDZ（突触后密度-95/Discs large/zona occlusionns-1）结构域相互作用对突触强度和 AMPAR 校正产生与 PICK1 表达观察到的相反的影响。这表明 AMPAR 亚基组成通过涉及 PICK1 PDZ 结构域相互作用的机制进行生理调节。这些发现表明，PICK1 可以下调海马 CA1 突触处 AMPAR 的 GluR2 含量，从而增加静息膜电位下的突触强度。
PICK1 (protein interacting with C kinase-1) regulates the surface expression of the AMPA receptor (AMPAR) GluR2 subunit, however, the functional consequences of this interaction are not well understood. Previous work has suggested that PICK1 promotes the internalization of AMPARs. However, we found that when PICK1 is virally expressed in the CA1 region of hippocampal slices, it causes an increase in AMPAR-mediated EPSC amplitude. This effect is associated with increased AMPAR rectification and sensitivity to polyamine toxin. These effects are blocked by PKC or calcium/calmodulin-dependent protein kinase II inhibitors, indicating that the virally expressed PICK1 signals through an endogenous kinase cascade. In contrast, blockade of interactions with GluR2 at the N-ethylmaleimide-sensitive factor site did not cause a change in subunit composition, suggesting that the effects of PICK1 are not simply a nonspecific consequence of removing AMPARs from the surface. Immunocytochemical and biochemical analyses in dissociated cultured hippocampal neurons show that PICK1 causes a decrease in endogenous GluR2 surface expression but no change in GluR1 surface levels. To address the physiological role of PICK1, we virally expressed C-terminal GluR2 peptides. Blockade of endogenous PICK1 PDZ (postsynaptic density-95/Discs large/zona occludens-1) domain interactions produced opposite effects on synaptic strength and AMPAR rectification to those observed with PICK1 expression. This demonstrates that AMPAR subunit composition is physiologically regulated through a mechanism involving PICK1 PDZ domain interactions. These findings suggest that PICK1 acts to downregulate the GluR2 content of AMPARs at hippocampal CA1 synapses, thereby increasing synaptic strength at resting membrane potentials.