A functional role of postsynaptic density-95-guanylate kinase-associated protein complex in regulating shank assembly and stability to Synapses
A functional role of postsynaptic density-95-guanylate kinase-associated protein complex in regulating shank assembly and stability to Synapses
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DOI：
10.1523/jneurosci.3314-04.2004
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发表时间：
2004-10-20
影响因子：
5.3
通讯作者：
Sala, C
中科院分区：
文献类型：
--
作者：
Romorini, S;Piccoli, G;Sala, C
突触后密度 (PSD) 蛋白包括支架蛋白、细胞骨架蛋白和信号蛋白，它们在结构和功能上与谷氨酸受体和其他突触后膜蛋白相互作用。调节 PSD 蛋白组装及其与突触关联的分子机制仍广为人知。我们通过观察鸟苷酸激酶相关蛋白 (GKAP) 的功能和 PSD-95 相互作用来研究 Shank1 靶向和突触组装的分子机制。当 Shank1 不与 GKAP 结合时，GKAP 与 Shank PSD-95-Discs Large-zona occlusionns-1 结构域结合，形成丝状和梭形结构，其中 Src 同源 3 结构域与锚蛋白重复结构域特异性相互作用，从而允许其通过新型分子间相互作用形式进行多聚化。令人惊讶的是，在 COS-7 细胞和海马神经元中，GKAP 与 Shank 形成不溶性聚集体，与热休克蛋白 70 和神经丝（错误折叠蛋白在其中积聚的聚集体的两个标记）共定位。然而，当这两种蛋白都过表达并与野生型 PSD-95 相关但与棕榈酰化缺陷型 PSD-95 相关时，这两种蛋白在 COS 细胞中组织成簇，在神经元中组织成突触簇。神经元突触活动诱导 Shank 和 GKAP 细胞内聚集和降解的形成。同样，无法结合 PSD-95 的 GKAP 突变体的过度表达会诱导神经元中的 Shank 聚集和降解。我们的数据表明 PSD-95-GKAP 复合物在柄和 PSD 蛋白组装以及突触稳定性中可能发挥功能和结构作用。
Postsynaptic density (PSD) proteins include scaffold, cytoskeletal, and signaling proteins that structurally and functionally interact with glutamate receptors and other postsynaptic membrane proteins. The molecular mechanisms regulating the assembly of PSD proteins and their associations with synapses are still widely unknown. We investigated the molecular mechanisms of Shank1 targeting and synapse assembly by looking at the function of guanylate kinase-associated protein ( GKAP) and PSD-95 interactions. Shank1 when it is not associated to GKAP, which binds to the Shank PSD-95-Discs Large-zona occludens-1 domain, forms filamentous and fusiform structures in which the Src homology 3 domain specifically interacts with the ankyrin repeat domain, thus allowing its multimerization via a novel form of intermolecular interaction. Surprisingly, in both COS-7 cells and hippocampal neurons, GKAP forms insoluble aggregates with Shank that colocalize with heat shock protein 70 and neurofilaments, two markers of the aggresomes in which misfolded proteins accumulate. However, the two proteins are organized in clusters in COS cells and synaptic clusters in neurons when both are overexpressed and associated with wild-type PSD-95, but not with palmitoylation-deficient PSD-95. Synaptic activity in neurons induces the formation of Shank and GKAP intracellular aggregation and degradation. Similarly, the overexpression of a GKAP mutant that is incapable of binding PSD-95 induces Shank aggregation and degradation in neurons. Our data suggest a possible functional and structural role of the PSD-95-GKAP complex in Shank and PSD protein assembly and stability to synapses.