Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California 94304, USA.
J Neurosci. 2012 Oct 24;32(43):14966-78. doi: 10.1523/JNEUROSCI.2215-12.2012.
Mutations in several postsynaptic proteins have recently been implicated in the molecular pathogenesis of autism and autism spectrum disorders (ASDs), including Neuroligins, Neurexins, and members of the ProSAP/Shank family, thereby suggesting that these genetic forms of autism may share common synaptic mechanisms. Initial studies of ASD-associated mutations in ProSAP2/Shank3 support a role for this protein in glutamate receptor function and spine morphology, but these synaptic phenotypes are not universally penetrant, indicating that other core facets of ProSAP2/Shank3 function must underlie synaptic deficits in patients with ASDs. In the present study, we have examined whether the ability of ProSAP2/Shank3 to interact with the cytoplasmic tail of Neuroligins functions to coordinate pre/postsynaptic signaling through the Neurexin-Neuroligin signaling complex in hippocampal neurons of Rattus norvegicus. Indeed, we find that synaptic levels of ProSAP2/Shank3 regulate AMPA and NMDA receptor-mediated synaptic transmission and induce widespread changes in the levels of presynaptic and postsynaptic proteins via Neurexin-Neuroligin transsynaptic signaling. ASD-associated mutations in ProSAP2/Shank3 disrupt not only postsynaptic AMPA and NMDA receptor signaling but also interfere with the ability of ProSAP2/Shank3 to signal across the synapse to alter presynaptic structure and function. These data indicate that ASD-associated mutations in a subset of synaptic proteins may target core cellular pathways that coordinate the functional matching and maturation of excitatory synapses in the CNS.
最近，一些突触后蛋白的突变被牵连到自闭症和自闭症谱系障碍（ASD）的分子发病机制中，包括神经连接素、神经连接蛋白和 ProSAP/Shank 家族成员，这表明这些自闭症的遗传形式可能共享共同的突触机制。对 ProSAP2/Shank3 中与 ASD 相关的突变的初步研究支持该蛋白在谷氨酸受体功能和棘突形态中的作用，但这些突触表型并非普遍存在，表明 ProSAP2/Shank3 功能的其他核心方面必须是 ASD 患者突触缺陷的基础。在本研究中，我们研究了 ProSAP2/Shank3 与神经连接素的细胞质尾巴相互作用的能力是否通过神经连接素-神经连接素信号复合物在大鼠海马神经元中协调前突触/后突触信号。事实上，我们发现 ProSAP2/Shank3 的突触水平调节 AMPA 和 NMDA 受体介导的突触传递，并通过神经连接素-神经连接素突触传递诱导广泛的突触前和突触后蛋白水平变化。ProSAP2/Shank3 中的 ASD 相关突变不仅破坏了突触后 AMPA 和 NMDA 受体信号，而且干扰了 ProSAP2/Shank3 通过突触传递信号以改变突触前结构和功能的能力。这些数据表明，一组突触蛋白中的 ASD 相关突变可能靶向协调中枢神经系统兴奋性突触功能匹配和成熟的核心细胞途径。
