1. Signal flow in the NMDA receptor–dependent phosphoproteome regulates postsynaptic plasticity for aversive learning.
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Funahashi, Yasuhiro, Ahammad, Rijwan Uddin, Zhang, Xinjian, Hossen, Emran, Kawatani, Masahiro, Nakamuta, Shinichi, Yoshimi, Akira, Wu, Minhua, Wang, Huanhuan, Wu, Mengya, Li, Xu, Faruk, Md Omar, Shohag, Md Hasanuzzaman, Lin, You-Hsin, Tsuboi, Daisuke, Nishioka, Tomoki, Kuroda, Keisuke, Amano, Mutsuki, Noda, Yukihiko, and Yamada, Kiyofumi
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RHO-associated kinases ,SCAFFOLD proteins ,NUCLEUS accumbens ,PROTEIN kinases ,RHO GTPases ,DENDRITIC spines - Abstract
Structural plasticity of dendritic spines in the nucleus accumbens (NAc) is crucial for learning from aversive experiences. Activation of NMDA receptors (NMDARs) stimulates Ca
2+ -dependent signaling that leads to changes in the actin cytoskeleton, mediated by the Rho family of GTPases, resulting in postsynaptic remodeling essential for learning. We investigated how phosphorylation events downstream of NMDAR activation drive the changes in synaptic morphology that underlie aversive learning. Large-scale phosphoproteomic analyses of protein kinase targets in mouse striatal/accumbal slices revealed that NMDAR activation resulted in the phosphorylation of 194 proteins, including RhoA regulators such as ARHGEF2 and ARHGAP21. Phosphorylation of ARHGEF2 by the Ca2+ -dependent protein kinase CaMKII enhanced its RhoGEF activity, thereby activating RhoA and its downstream effector Rho-associated kinase (ROCK/Rho-kinase). Further phosphoproteomic analysis identified 221 ROCK targets, including the postsynaptic scaffolding protein SHANK3, which is crucial for its interaction with NMDARs and other postsynaptic scaffolding proteins. ROCK-mediated phosphorylation of SHANK3 in the NAc was essential for spine growth and aversive learning. These findings demonstrate that NMDAR activation initiates a phosphorylation cascade crucial for learning and memory. Editor's summary: A component of the strengthened synaptic transmission that occurs in learning and memory is the growth of protrusions on neurons called dendritic spines, which requires activation of the NMDAR family of receptors in the nucleus accumbens. Funahashi et al. delineated the signaling pathway downstream of NMDARs that mediated aversive learning, which enables the identification, prediction, and avoidance of dangerous situations. The authors characterized the proteins phosphorylated in response to NMDAR activation and the kinases responsible. Dendritic spine growth and aversive learning were attenuated when the cytoskeleton-regulating kinase ROCK was pharmacologically inhibited or genetically ablated or when the ROCK-mediated phosphorylation of a specific substrate, the scaffolding protein SHANK3, was blocked in the nucleus accumbens. Thus, the phosphorylation of SHANK3 by ROCK is crucial for the changes in the neuronal actin cytoskeleton that support aversive learning. —Wei Wong [ABSTRACT FROM AUTHOR]- Published
- 2024
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