101
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Wei Z, Wu G, Chen BS. Regulation of SAP102 Synaptic Targeting by Phosphorylation. Mol Neurobiol 2017; 55:6215-6226. [PMID: 29282697 DOI: 10.1007/s12035-017-0836-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/12/2017] [Indexed: 11/29/2022]
Abstract
Synapse-associated protein 102 (SAP102) is a scaffolding protein highly expressed early in development and plays a critical role in mediating glutamate receptor trafficking during synaptogenesis. Mutations in human SAP102 have been reported to cause intellectual disability, which is thought to be due to mislocalization of the mutant protein. However, little is known about the regulation of SAP102 synaptic targeting. Here, we investigate the role of phosphorylation of SAP102 in regulating its synaptic targeting. Previous studies have shown that synaptic targeting of SAP102 is regulated by C-terminal splicing. We now identify a phosphorylation site, serine 632, within the C-terminal alternatively spliced region, which is phosphorylated by casein kinase II (CK2). We show that Ser632 on SAP102 is phosphorylated in vitro, in heterologous cells, and in neurons. Moreover, we demonstrate that synaptic enrichment of SAP102 is increased by Ser632 phosphorylation. Consistently, elevation of synaptic activity that suppresses Ser632 phosphorylation reduces synaptic enrichment of SAP102. Furthermore, the mobility of SAP102 is decreased by Ser632 phosphorylation. Therefore, not only SAP102 synaptic targeting but also its mobility is regulated by Ser632 phosphorylation. These data provide evidence for a novel mechanism in regulating SAP102 function and glutamate receptor trafficking.
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Affiliation(s)
- Zhe Wei
- Department of Neuroscience and Regenerative Medicine and Department of Neurology, Medical College of Georgia, Augusta University, CA3008, 1120 15th Street, Augusta, GA, 30912, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Bo-Shiun Chen
- Department of Neuroscience and Regenerative Medicine and Department of Neurology, Medical College of Georgia, Augusta University, CA3008, 1120 15th Street, Augusta, GA, 30912, USA.
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102
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Zhu J, Zhou Q, Shang Y, Li H, Peng M, Ke X, Weng Z, Zhang R, Huang X, Li SS, Feng G, Lu Y, Zhang M. Synaptic Targeting and Function of SAPAPs Mediated by Phosphorylation-Dependent Binding to PSD-95 MAGUKs. Cell Rep 2017; 21:3781-3793. [DOI: 10.1016/j.celrep.2017.11.107] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/13/2017] [Accepted: 11/29/2017] [Indexed: 10/18/2022] Open
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103
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Milgrom-Hoffman M, Humbert PO. Regulation of cellular and PCP signalling by the Scribble polarity module. Semin Cell Dev Biol 2017; 81:33-45. [PMID: 29154823 DOI: 10.1016/j.semcdb.2017.11.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 10/18/2022]
Abstract
Since the first identification of the Scribble polarity module proteins as a new class of tumour suppressors that regulate both cell polarity and proliferation, an increasing amount of evidence has uncovered a broader role for Scribble, Dlg and Lgl in the control of fundamental cellular functions and their signalling pathways. Here, we review these findings as well as discuss more specifically the role of the Scribble module in PCP signalling.
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Affiliation(s)
- Michal Milgrom-Hoffman
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Patrick O Humbert
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia; Department of Biochemistry & Molecular Biology, University of Melbourne, Melbourne, Victoria 3010, Australia; Department of Pathology, University of Melbourne, Melbourne, Victoria 3010, Australia.
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104
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Zeng M, Ye F, Xu J, Zhang M. PDZ Ligand Binding-Induced Conformational Coupling of the PDZ-SH3-GK Tandems in PSD-95 Family MAGUKs. J Mol Biol 2017; 430:69-86. [PMID: 29138001 DOI: 10.1016/j.jmb.2017.11.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/20/2017] [Accepted: 11/08/2017] [Indexed: 10/18/2022]
Abstract
Discs large (DLG) MAGUKs are abundantly expressed in glutamatergic synapses, crucial for synaptic transmission, and plasticity by anchoring various postsynaptic components including glutamate receptors, downstream scaffold proteins and signaling enzymes. Different DLG members have shared structures and functions, but also contain unique features. How DLG family proteins function individually and cooperatively is largely unknown. Here, we report that PSD-95 PDZ3 directly couples with SH3-GK tandem in a PDZ ligand binding-dependent manner, and the coupling can promote PSD-95 dimerization and multimerization. Aided by sortase-mediated protein ligation and selectively labeling, we elucidated the PDZ3/SH3-GK conformational coupling mechanism using NMR spectroscopy. We further demonstrated that PSD-93, but not SAP102, can also undergo PDZ3 ligand binding-induced conformational coupling with SH3-GK and form homo-oligomers. Interestingly, PSD-95 and PSD-93 can also form ligand binding-induced hetero-oligomers, suggesting a cooperative assembly mechanism for the mega-N-methyl-d-aspartate receptor synaptic signaling complex. Finally, we provide evidence showing that ligand binding-induced conformational coupling between PDZ and SH3-GK is a common feature for other MAGUKs including CASK and PALS1.
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Affiliation(s)
- Menglong Zeng
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Fei Ye
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jia Xu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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105
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Kato AS, Witkin JM. Auxiliary subunits of AMPA receptors: The discovery of a forebrain-selective antagonist, LY3130481/CERC-611. Biochem Pharmacol 2017; 147:191-200. [PMID: 28987594 DOI: 10.1016/j.bcp.2017.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/27/2017] [Indexed: 12/11/2022]
Abstract
Drugs originate from the discovery of compounds, natural or synthetic, that bind to proteins (receptors, enzymes, transporters, etc.), the interaction of which modulates biological cascades that have potential therapeutic benefit. Rational strategies for identifying novel drug therapies are typically based on knowledge of the structure of the target proteins and the design of new chemical entities that modulate these proteins in a beneficial manner. The present review discusses a novel approach to drug discovery based on the identification and characterization of auxiliary proteins, the transmembrane AMPA receptor regulatory proteins (TARPs) that are associated with AMPA receptors. Utilizing these auxiliary proteins in compound screening led to the discovery of the TARP-dependent-AMPA forebrain selective receptor antagonist (TDAA), LY3130481/CERC-611 that is currently in clinical development for epilepsy.
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Affiliation(s)
- Akihiko S Kato
- Neuroscience Discovery Research, Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN 46285-0510, United States.
| | - Jeffrey M Witkin
- Neuroscience Discovery Research, Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN 46285-0510, United States.
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106
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Mechanisms of MAGUK-mediated cellular junctional complex organization. Curr Opin Struct Biol 2017; 48:6-15. [PMID: 28917202 DOI: 10.1016/j.sbi.2017.08.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 01/01/2023]
Abstract
Membrane-associated guanylate kinases (MAGUKs) are a family of scaffold proteins that are enriched in cellular junctions and essential for tissue development and homeostasis. Mutations of MAGUKs are linked to many human diseases including cancers, psychiatric disorders, and intellectual disabilities. MAGUKs share a common PDZ-SH3-GK tandem domain organization at the C-terminal end. In this review, we summarize the mechanistic basis governing target recognition and regulations of this binding by the PDZ-SH3-GK tandem of various MAGUKs. We also discuss recent discoveries showing unique folding features of MAGUK PDZ-SH3-GK tandems that facilitate ligand-induced oligomerization of MAGUKs and phase transition of MAGUK-assembled synaptic signaling complexes.
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107
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Jang S, Lee H, Kim E. Synaptic adhesion molecules and excitatory synaptic transmission. Curr Opin Neurobiol 2017; 45:45-50. [DOI: 10.1016/j.conb.2017.03.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/04/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022]
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