Glutamate-induced declustering of post-synaptic adaptor protein Cupidin (Homer 2/vesl-2) in cultured cerebellar granule cells
Glutamate-induced declustering of post-synaptic adaptor protein Cupidin (Homer 2/vesl-2) in cultured cerebellar granule cells
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DOI：
10.1046/j.1471-4159.2003.02003.x
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发表时间：
2003-10-01
影响因子：
4.7
通讯作者：
Furuichi, T
中科院分区：
文献类型：
--
作者：
Shiraishi, Y;Mizutani, A;Furuichi, T
Cupidin(Homer2/vesl-2)是一种突触后适配器蛋白，与谷氨酸受体复合体和肌动蛋白细胞骨架结合。我们分析了丘比丁在小鼠小脑颗粒细胞中的发育和活性依赖的定位。在出生后发育的小脑中，Cupidin主要定位于与苔藓纤维终末相连的突触后颗粒细胞，而在成年小脑中表达较少。在体外培养的颗粒细胞中，Cupidin以突触和突触外点状簇状存在，主要与肌动蛋白-细胞骨架结合伙伴F-肌动蛋白和Drebrin以及突触后支架蛋白PSD-95共存。在谷氨酸刺激下，丘比丁团簇迅速解离，蛋白质没有降解，在短期但不持续的刺激下，在没有谷氨酸的情况下，它们在孵育后恢复。谷氨酸诱导的Cupidin的去聚集先于F-肌动蛋白和Drebrin，由NMDA受体介导的钙内流引起，然后是MAPK/ERK和蛋白酪氨酸激酶的下游通路。翻译后修饰的特定异构体减少取决于钙依赖的蛋白磷酸酶活性。在培养的海马神经元中，Hmer家族成员Hmer 1、Cupidin/Hmer 2和Hmer 3表现出类似的谷氨酸诱导的去集聚。我们认为，Cupidin作为一种移动适配器蛋白，随着突触的活动而改变分布状态，聚集的或非聚集的。
Cupidin (Homer 2/vesl-2) is a post-synaptic adaptor protein that associates with glutamate receptor complexes and the actin cytoskeleton. We analyzed the developmental and activity-dependent localization of Cupidin in mouse cerebellar granule cells. Cupidin is predominantly localized to granule cell post-synapses connecting with mossy fiber terminals in developing post-natal cerebellum, but is diminished in adult cerebellum. In cultured granule cells 7 days in vitro, Cupidin was present as synaptic and extra-synaptic punctate clusters that largely co-localized with the actin-cytoskeletal binding partners F-actin and drebrin, as well as a post-synaptic scaffold protein PSD-95. Upon stimulation with glutamate, Cupidin clusters were rapidly dissociated without protein degradation, and by short-term but not sustained stimulation they were recovered after post-incubation without glutamate. The glutamate-induced declustering of Cupidin preceded that of F-actin and drebrin, was elicited by NMDA receptor-mediated Ca2+ influx, and was followed by a downstream pathway including MAPK/ERK and protein tyrosine kinase. Specific isoforms with post-translational modification were reduced depending on Ca2+-dependent protein phosphatase activity. In cultured hippocampal neurons, Homer family members Homer 1, Cupidin/Homer 2 and Homer 3 showed similar glutamate-induced declustering. We suggest that Cupidin acts as a mobile adaptor protein that changes the distribution states, clustered versus declustered, in response to synaptic activity.