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Mo SJ, Cho Y, Choi BI, Lee D, Kim H. PKA-dependent phosphorylation of IP3K-A at Ser119 regulates a binding affinity with EB3. Biochem Biophys Res Commun 2019; 508:52-59. [PMID: 30466786 DOI: 10.1016/j.bbrc.2018.11.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 11/07/2018] [Indexed: 11/16/2022]
Abstract
Microtubule-associated end-binding protein 3 (EB3) accumulates asymmetrically at the tip-end of growing microtubules, providing a central platform for linking various cellular components. EB3 orchestrates microtubule dynamics and targeting, enabling diverse processes within neurons. Inositol 1, 4, 5-trisphosphate 3-kinase A (IP3K-A; also known as ITPKA) is a neuron-enriched protein that binds to microtubules by PKA-dependent manners. In this study, we found that IP3K-A binds to EB3 and their binding affinity is precisely regulated by protein kinase A (PKA)-dependent phosphorylation of IP3K-A at Ser119 (pSer119). We also revealed that the complex of IP3K-A and EB3 dissociates and reassociates rapidly during chemically induced LTP (cLTP) condition. This dynamic rearrangement of IP3K-A and EB3 complex will contribute remodeling of microtubule cytoskeleton allowing effective structural plasticity in response to synaptic stimulations.
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Affiliation(s)
- Seo Jung Mo
- Department of Anatomy, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| | - Yongsang Cho
- Gachon Liberal Arts College, Gachon University, Seongnam-si, Republic of Korea
| | - Byung-Il Choi
- Department of Anatomy, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| | - Dongmin Lee
- Department of Anatomy, College of Medicine, Korea University, Seoul 02841, Republic of Korea.
| | - Hyun Kim
- Department of Anatomy, College of Medicine, Korea University, Seoul 02841, Republic of Korea.
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Choi B, Lee HW, Mo S, Kim JY, Kim HW, Rhyu IJ, Hong E, Lee YK, Choi JS, Kim CH, Kim H. Inositol 1,4,5-trisphosphate 3-kinase A overexpressed in mouse forebrain modulates synaptic transmission and mGluR-LTD of CA1 pyramidal neurons. PLoS One 2018; 13:e0193859. [PMID: 29617377 PMCID: PMC5884490 DOI: 10.1371/journal.pone.0193859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 02/20/2018] [Indexed: 11/18/2022] Open
Abstract
Inositol 1,4,5-trisphosphate 3-kinase A (IP3K-A) regulates the level of the inositol polyphosphates, inositol trisphosphate (IP3) and inositol tetrakisphosphate to modulate cellular signaling and intracellular calcium homeostasis in the central nervous system. IP3K-A binds to F-actin in an activity-dependent manner and accumulates in dendritic spines, where it is involved in the regulation of synaptic plasticity. IP3K-A knockout mice exhibit deficits in some forms of hippocampus-dependent learning and synaptic plasticity, such as long-term potentiation in the dentate gyrus synapses of the hippocampus. In the present study, to further elucidate the role of IP3K-A in the brain, we developed a transgenic (Tg) mouse line in which IP3K-A is conditionally overexpressed approximately 3-fold in the excitatory neurons of forebrain regions, including the hippocampus. The Tg mice showed an increase in both presynaptic release probability of evoked responses, along with bigger synaptic vesicle pools, and miniature excitatory postsynaptic current amplitude, although the spine density or the expression levels of the postsynaptic density-related proteins NR2B, synaptotagmin 1, and PSD-95 were not affected. Hippocampal-dependent learning and memory tasks, including novel object recognition and radial arm maze tasks, were partially impaired in Tg mice. Furthermore, (R,S)-3,5-dihydroxyphenylglycine-induced metabotropic glutamate receptor long-term depression was inhibited in Tg mice and this inhibition was dependent on protein kinase C but not on the IP3 receptor. Long-term potentiation and depression dependent on N-methyl-d-aspartate receptor were marginally affected in Tg mice. In summary, this study shows that overexpressed IP3K-A plays a role in some forms of hippocampus-dependent learning and memory tasks as well as in synaptic transmission and plasticity by regulating both presynaptic and postsynaptic functions.
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Affiliation(s)
- Byungil Choi
- Department of Anatomy, College of Medicine, Korea University, Brain Korea, Seoul, Korea
| | - Hyun Woo Lee
- Department of Anatomy, College of Medicine, Korea University, Brain Korea, Seoul, Korea
| | - Seojung Mo
- Department of Anatomy, College of Medicine, Korea University, Brain Korea, Seoul, Korea
| | - Jin Yong Kim
- Department of Anatomy, College of Medicine, Korea University, Brain Korea, Seoul, Korea
| | - Hyun Wook Kim
- Department of Anatomy, College of Medicine, Korea University, Brain Korea, Seoul, Korea
| | - Im Joo Rhyu
- Department of Anatomy, College of Medicine, Korea University, Brain Korea, Seoul, Korea
| | - Eunhwa Hong
- Department of Psychology, Korea University, Seoul, Korea
| | - Yeon Kyung Lee
- Department of Psychology, Korea University, Seoul, Korea
| | - June-Seek Choi
- Department of Psychology, Korea University, Seoul, Korea
| | - Chong-Hyun Kim
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology and Neuroscience Program, Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, Korea
- * E-mail: (C-HK); (HK)
| | - Hyun Kim
- Department of Anatomy, College of Medicine, Korea University, Brain Korea, Seoul, Korea
- * E-mail: (C-HK); (HK)
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Inositol 1,4,5-trisphosphate 3-kinase a functions as a scaffold for synaptic Rac signaling. J Neurosci 2009; 29:14039-49. [PMID: 19890013 DOI: 10.1523/jneurosci.2483-09.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Activity-dependent alterations of synaptic contacts are crucial for synaptic plasticity. The formation of new dendritic spines and synapses is known to require actin cytoskeletal reorganization specifically during neural activation phases. Yet the site-specific and time-dependent mechanisms modulating actin dynamics in mature neurons are not well understood. In this study, we show that actin dynamics in spines is regulated by a Rac anchoring and targeting function of inositol 1,4,5-trisphosphate 3-kinase A (IP(3)K-A), independent of its kinase activity. On neural activation, IP(3)K-A bound directly to activated Rac1 and recruited it to the actin cytoskeleton in the postsynaptic area. This focal targeting of activated Rac1 induced spine formation through actin dynamics downstream of Rac signaling. Consistent with the scaffolding role of IP(3)K-A, IP(3)K-A knock-out mice exhibited defects in accumulation of PAK1 by long-term potentiation-inducing stimulation. This deficiency resulted in a reduction in the reorganization of actin cytoskeletal structures in the synaptic area of dentate gyrus. Moreover, IP(3)K-A knock-out mice showed deficits of synaptic plasticity in perforant path and in hippocampal-dependent memory performances. These data support a novel model in which IP(3)K-A is critical for the spatial and temporal regulation of spine actin remodeling, synaptic plasticity, and learning and memory via an activity-dependent Rac scaffolding mechanism.
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Abstract
Kainate receptors form a family of ionotropic glutamate receptors that appear to play a special role in the regulation of the activity of synaptic networks. This review first describes briefly the molecular and pharmacological properties of native and recombinant kainate receptors. It then attempts to outline the general principles that appear to govern the function of kainate receptors in the activity of synaptic networks under physiological conditions. It subsequently describes the way that kainate receptors are involved in synaptic integration, synaptic plasticity, the regulation of neurotransmitter release and the control of neuronal excitability, and the manner in which they might play an important role in synaptogenesis and synaptic maturation. These functions require the proper subcellular localization of kainate receptors in specific functional domains of the neuron, necessitating complex cellular and molecular trafficking events. We show that our comprehension of these mechanisms is just starting to emerge. Finally, this review presents evidence that implicates kainate receptors in pathophysiological conditions such as epilepsy, excitotoxicity and pain, and that shows that these receptors represent promising therapeutic targets.
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Affiliation(s)
- Paulo Pinheiro
- CNRS UMR 5091, Laboratoire "Physiologie Cellulaire de la Synapse", Bordeaux Neuroscience Institute, University of Bordeaux, 33077 Bordeaux Cedex, France
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