Haglerød C, Hussain S, Nakamura Y, Xia J, Haug F-M S, Ottersen O P, Henley J M, Davanger S
Institute of Basic Medical Sciences, Division of Anatomy, University of Oslo, Oslo, Norway.
School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
Neuroscience. 2017 Mar 6;344:102-112. doi: 10.1016/j.neuroscience.2016.12.042. Epub 2017 Jan 3.
Previous studies have indicated that presynaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPARs) contribute to the regulation of neurotransmitter release. In hippocampal synapses, the presynaptic surface expression of several AMPAR subunits, including GluA2, is regulated in a ligand-dependent manner. However, the molecular mechanisms underlying the presynaptic trafficking of AMPARs are still unknown. Here, using bright-field immunocytochemistry, western blots, and quantitative immunogold electron microscopy of the hippocampal CA1 area from intact adult rat brain, we demonstrate the association of AMPA receptors with the presynaptic active zone and with small presynaptic vesicles, in Schaffer collateral synapses in CA1 of the hippocampus. Furthermore, we show that GluA2 and protein interacting with C kinase 1 (PICK1) are colocalized at presynaptic vesicles. Similar to postsynaptic mechanisms, overexpression of either PICK1 or pep2m, which inhibit the N-ethylmaleimide sensitive fusion protein (NSF)-GluA2 interaction, decreases the concentration of GluA2 in the presynaptic active zone membrane. These data suggest that the interacting proteins PICK1 and NSF act as regulators of presynaptic GluA2-containing AMPAR trafficking between the active zone and a vesicle pool that may provide the basis of presynaptic components of synaptic plasticity.
先前的研究表明，突触前α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体（AMPARs）有助于调节神经递质的释放。在海马突触中，包括GluA2在内的几种AMPAR亚基的突触前表面表达以配体依赖的方式受到调节。然而，AMPARs突触前转运的分子机制仍然未知。在这里，我们使用来自成年大鼠完整大脑海马CA1区的明场免疫细胞化学、蛋白质免疫印迹和定量免疫金电子显微镜技术，证明了在海马CA1区的Schaffer侧支突触中，AMPA受体与突触前活性区和小突触前囊泡相关联。此外，我们还表明，GluA2和与C激酶1相互作用的蛋白质（PICK1）在突触前囊泡中共定位。与突触后机制类似，抑制N-乙基马来酰亚胺敏感融合蛋白（NSF）-GluA2相互作用的PICK1或pep2m的过表达，会降低突触前活性区膜中GluA2的浓度。这些数据表明，相互作用蛋白PICK1和NSF作为突触前含GluA2的AMPAR在活性区和囊泡池之间转运的调节因子，这可能为突触可塑性的突触前成分提供基础。
