Department of Anatomy and Cell Biology, Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical School, Kansas City, KS, USA.
Channels (Austin). 2011 Sep-Oct;5(5):432-9. doi: 10.4161/chan.5.5.16472. Epub 2011 Sep 1.
Recent findings demonstrate that synaptic channels are directly involved in the formation and maintenance of synapses by interacting with synapse organizers. The synaptic channels on the pre- and postsynaptic membranes possess non-conducting roles in addition to their functional roles as ion-conducting channels required for synaptic transmission. For example, presynaptic voltage-dependent calcium channels link the target-derived synapse organizer laminin β2 to cytomatrix of the active zone and function as scaffolding proteins to organize the presynaptic active zones. Furthermore, postsynaptic δ2-type glutamate receptors organize the synapses by forming transsynaptic protein complexes with presynaptic neurexins through synapse organizer cerebellin 1 precursor proteins. Interestingly, the synaptic clustering of AMPA receptors is regulated by neuronal activity-regulated pentraxins, while postsynaptic differentiation is induced by the interaction of postsynaptic calcium channels and thrombospondins. This review will focus on the non-conducting functions of ion-channels that contribute to the synapse formation in concert with synapse organizers and active-zone-specific proteins.
最近的研究结果表明，突触通道通过与突触组织者相互作用，直接参与突触的形成和维持。前突触和后突触膜上的突触通道除了作为离子通道发挥功能作用（对于突触传递是必需的）外，还具有非传导作用。例如，前突触电压依赖性钙通道将靶源性突触组织者层粘连蛋白β2与活性区的细胞基质连接起来，并作为支架蛋白发挥作用，以组织前突触活性区。此外，后突触 δ2 型谷氨酸受体通过突触组织者小脑蛋白前体与前突触神经连接蛋白形成跨突触蛋白复合物，从而组织突触。有趣的是，AMPA 受体的突触聚集受神经元活动调节的五聚体蛋白调节，而突触后分化则是由突触后钙通道和血栓素结合蛋白的相互作用诱导的。这篇综述将重点介绍离子通道的非传导功能，这些功能与突触组织者和活性区特异性蛋白一起协同促进突触的形成。
