Postsynaptic density scaffold SAP102 regulates cortical synapse development through EphB and PAK signaling pathway.
Postsynaptic density scaffold SAP102 regulates cortical synapse development through EphB and PAK signaling pathway.
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突触后密度支架SAP102通过EPHB和PAK信号通路调节皮质突触的发育。
DOI：
10.1523/jneurosci.2896-12.2013
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发表时间：
2013-03-13
期刊：
影响因子：
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通讯作者：
Constantine-Paton M
中科院分区：
文献类型：
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作者：
Murata Y;Constantine-Paton M
Membrane associated guanylate kinases (MAGUKs), including SAP102, PSD-95, PSD-93 and SAP97, are scaffolding proteins for ionotropic glutamate receptors at excitatory synapses. MAGUKs play critical roles in synaptic plasticity; however, details of signaling roles for each MAGUK remain largely unknown. Here we report that SAP102 regulates cortical synapse development through the EphB and PAK signaling pathways. Using lentivirus-delivered shRNAs, we found that SAP102 and PSD-95, but not PSD-93, are necessary for excitatory synapse formation and synaptic AMPA receptor localization in developing mouse cortical neurons. SAP102 knockdown (KD) increased numbers of elongated dendritic filopodia, which is often observed in mouse models and human patients with mental retardation. Further analysis revealed that SAP102 co-immunoprecipitated the receptor tyrosine kinase EphB2 and RacGEF Kalirin-7 in neonatal cortex, and SAP102 KD reduced surface expression and dendritic localization of EphB. Moreover, SAP102 KD prevented reorganization of actin filaments, synapse formation and synaptic AMPAR trafficking in response to EphB activation triggered by its ligand ephrinB. Lastly, p21-activated kinases (PAKs) were down-regulated in SAP102 KD neurons. These results demonstrate that SAP102 has unique roles in cortical synapse development by mediating EphB and its downstream PAK signaling pathway. Both SAP102 and PAKs are associated with X-linked mental retardation in humans; thus, synapse formation mediated by EphB/SAP102/PAK signaling in the early postnatal brain may be crucial for cognitive development.
