National Center for Protein Science Shanghai, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, 333 Haike Road, Shanghai 201203, China; Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Cell Rep. 2017 Dec 26;21(13):3781-3793. doi: 10.1016/j.celrep.2017.11.107.
The PSD-95/SAPAP/Shank complex functions as the major scaffold in orchestrating the formation and plasticity of the post-synaptic densities (PSDs). We previously demonstrated that the exquisitely specific SAPAP/Shank interaction is critical for Shank synaptic targeting and Shank-mediated synaptogenesis. Here, we show that the PSD-95/SAPAP interaction, SAPAP synaptic targeting, and SAPAP-mediated synaptogenesis require phosphorylation of the N-terminal repeat sequences of SAPAPs. The atomic structure of the PSD-95 guanylate kinase (GK) in complex with a phosphor-SAPAP repeat peptide, together with biochemical studies, reveals the molecular mechanism underlying the phosphorylation-dependent PSD-95/SAPAP interaction, and it also provides an explanation of a PSD-95 mutation found in patients with intellectual disabilities. Guided by the structural data, we developed potent non-phosphorylated GK inhibitory peptides capable of blocking the PSD-95/SAPAP interaction and interfering with PSD-95/SAPAP-mediated synaptic maturation and strength. These peptides are genetically encodable for investigating the functions of the PSD-95/SAPAP interaction in vivo.
PSD-95/SAPAP/Shank 复合物作为主要支架，协调突触后密度（PSD）的形成和可塑性。我们之前的研究表明，SAPAP/Shank 相互作用的高度特异性对于 Shank 的突触靶向和 Shank 介导的突触发生至关重要。在这里，我们表明 PSD-95/SAPAP 相互作用、SAPAP 的突触靶向和 SAPAP 介导的突触发生需要 SAPAPs 的 N 端重复序列的磷酸化。PSD-95 鸟苷酸激酶 (GK) 与磷酸化 SAPAP 重复肽的复合物的原子结构，以及生化研究，揭示了磷酸化依赖性 PSD-95/SAPAP 相互作用的分子机制，也为在智力障碍患者中发现的 PSD-95 突变提供了一种解释。在结构数据的指导下，我们开发了有效的非磷酸化 GK 抑制肽，能够阻断 PSD-95/SAPAP 相互作用，并干扰 PSD-95/SAPAP 介导的突触成熟和强度。这些肽可遗传编码，用于研究 PSD-95/SAPAP 相互作用在体内的功能。
