Epilepsy protein myoclonin1 interacts with inositol 1,4,5-trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulum
Aim: Mutations in the EFHC1 gene have been identified in patients with various epilepsies, including juvenile myoclonic epilepsy (JME). Mice with Efhc1 deficiency also exhibit epileptic phenotypes. The protein myoclonin1, encoded by EFHC1, is not expressed in neurons but in cells with motile cilia,...
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| Format: | Article |
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Open Exploration Publishing Inc.
2025-07-01
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| Series: | Exploration of Neuroscience |
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| Online Access: | https://www.explorationpub.com/uploads/Article/A100699/100699.pdf |
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| author | Toshimitsu Suzuki Kripamoy Aguan Hideaki Mizuno Ikuyo Inoue Katsuhiko Mikoshiba Atsushi Miyawaki Kazuhiro Yamakawa |
| author_facet | Toshimitsu Suzuki Kripamoy Aguan Hideaki Mizuno Ikuyo Inoue Katsuhiko Mikoshiba Atsushi Miyawaki Kazuhiro Yamakawa |
| author_sort | Toshimitsu Suzuki |
| collection | DOAJ |
| description | Aim: Mutations in the EFHC1 gene have been identified in patients with various epilepsies, including juvenile myoclonic epilepsy (JME). Mice with Efhc1 deficiency also exhibit epileptic phenotypes. The protein myoclonin1, encoded by EFHC1, is not expressed in neurons but in cells with motile cilia, including choroid plexus and ependymal cells lining of brain ventricles. However, the molecular mechanisms by which EFHC1 mutations cause epilepsy remain unclear. Because of the involvement of inositol 1,4,5-trisphosphate receptor type 1 (IP3R1) in epileptic phenotypes and the involvement of myoclonin1 in calcium ions (Ca2+) signaling, we investigated possible functional interplay between myoclonin1 and IP3R1. Methods: We performed immunohistochemical staining of brain tissues and co-immunoprecipitation assay of myoclonin1 and IP3R1, and Ca2+ imaging analyses using human HeLa.S3, mouse embryonic fibroblasts, or glial cells derived from Efhc1 homozygous knockout (Efhc1–/–) and wild-type (WT) littermates. Results: Myoclonin1 was revealed to be well co-expressed with IP3R1 at choroid plexus and ependymal cells, and these two proteins bound to each other. Endoplasmic reticulum (ER) of Efhc1-deficient mouse (Efhc1–/–) cells showed larger amounts of Ca2+ than that of WT mice, and IP3-induced Ca2+ release (IICR) from ER was higher in Efhc1–/– cells than that of WT. Furthermore, myoclonin1 was revealed to interact with beta subunit of glucosidase II (PRKCSH), also known as a protein kinase C substrate 80K-H, which interacts with IP3R1. Myoclonin1 further binds to IP3R2 and IP3R3. Conclusions: These results indicate that myoclonin1 modulates ER-Ca2+ homeostasis through interactions with IP3Rs and PRKCSH, and suggest that myoclonin1 dysfunctions cause impaired intracellular Ca2+ mobilization. Its relevance to the epileptic phenotypes of patients with EFHC1 mutations is now of interest. |
| format | Article |
| id | doaj-art-5fddd54312be4ca2add1736adc4ac2bb |
| institution | Kabale University |
| issn | 2834-5347 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Open Exploration Publishing Inc. |
| record_format | Article |
| series | Exploration of Neuroscience |
| spelling | doaj-art-5fddd54312be4ca2add1736adc4ac2bb2025-08-20T03:50:16ZengOpen Exploration Publishing Inc.Exploration of Neuroscience2834-53472025-07-01410069910.37349/en.2025.100699Epilepsy protein myoclonin1 interacts with inositol 1,4,5-trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulumToshimitsu Suzuki0https://orcid.org/0000-0003-0585-5692Kripamoy Aguan1Hideaki Mizuno2https://orcid.org/0000-0002-6983-5255Ikuyo Inoue3Katsuhiko Mikoshiba4Atsushi Miyawaki5https://orcid.org/0000-0002-0671-4376Kazuhiro Yamakawa6https://orcid.org/0000-0002-1478-4390Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan; Laboratory for Neurogenetics, RIKEN Center for Brain Science (CBS), Wako 351-0198, JapanLaboratory for Neurogenetics, RIKEN Center for Brain Science (CBS), Wako 351-0198, Japan; Current address: Department of Biotechnology and Bioinformatics, North Eastern Hill University (NEHU), Shillong 793022, IndiaLaboratory for Cell Function Dynamics, RIKEN Center for Brain Science (CBS), Wako 351-0198, Japan; Current address: Laboratory of Biomolecular Network Dynamics, Biochemistry, Molecular and Structural Biology Section, Department of Chemistry, KU Leuven, 3001 Leuven, BelgiumLaboratory for Neurogenetics, RIKEN Center for Brain Science (CBS), Wako 351-0198, JapanCalcium Oscillation Project, International Cooperative Research Project-Solution Oriented Research for Science and Technology, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan; Laboratory for Developmental Neurobiology, RIKEN Center for Brain Science (CBS), Wako 351-0198, Japan; Current address: Laboratory for Cell Calcium Signaling, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, ChinaLaboratory for Cell Function Dynamics, RIKEN Center for Brain Science (CBS), Wako 351-0198, JapanDepartment of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan; Laboratory for Neurogenetics, RIKEN Center for Brain Science (CBS), Wako 351-0198, JapanAim: Mutations in the EFHC1 gene have been identified in patients with various epilepsies, including juvenile myoclonic epilepsy (JME). Mice with Efhc1 deficiency also exhibit epileptic phenotypes. The protein myoclonin1, encoded by EFHC1, is not expressed in neurons but in cells with motile cilia, including choroid plexus and ependymal cells lining of brain ventricles. However, the molecular mechanisms by which EFHC1 mutations cause epilepsy remain unclear. Because of the involvement of inositol 1,4,5-trisphosphate receptor type 1 (IP3R1) in epileptic phenotypes and the involvement of myoclonin1 in calcium ions (Ca2+) signaling, we investigated possible functional interplay between myoclonin1 and IP3R1. Methods: We performed immunohistochemical staining of brain tissues and co-immunoprecipitation assay of myoclonin1 and IP3R1, and Ca2+ imaging analyses using human HeLa.S3, mouse embryonic fibroblasts, or glial cells derived from Efhc1 homozygous knockout (Efhc1–/–) and wild-type (WT) littermates. Results: Myoclonin1 was revealed to be well co-expressed with IP3R1 at choroid plexus and ependymal cells, and these two proteins bound to each other. Endoplasmic reticulum (ER) of Efhc1-deficient mouse (Efhc1–/–) cells showed larger amounts of Ca2+ than that of WT mice, and IP3-induced Ca2+ release (IICR) from ER was higher in Efhc1–/– cells than that of WT. Furthermore, myoclonin1 was revealed to interact with beta subunit of glucosidase II (PRKCSH), also known as a protein kinase C substrate 80K-H, which interacts with IP3R1. Myoclonin1 further binds to IP3R2 and IP3R3. Conclusions: These results indicate that myoclonin1 modulates ER-Ca2+ homeostasis through interactions with IP3Rs and PRKCSH, and suggest that myoclonin1 dysfunctions cause impaired intracellular Ca2+ mobilization. Its relevance to the epileptic phenotypes of patients with EFHC1 mutations is now of interest.https://www.explorationpub.com/uploads/Article/A100699/100699.pdfefhc1myoclonin1juvenile myoclonic epilepsyinositol 145-trisphosphate receptorprotein kinase c substrate 80k-hendoplasmic reticulum-calcium ions store |
| spellingShingle | Toshimitsu Suzuki Kripamoy Aguan Hideaki Mizuno Ikuyo Inoue Katsuhiko Mikoshiba Atsushi Miyawaki Kazuhiro Yamakawa Epilepsy protein myoclonin1 interacts with inositol 1,4,5-trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulum Exploration of Neuroscience efhc1 myoclonin1 juvenile myoclonic epilepsy inositol 1 4 5-trisphosphate receptor protein kinase c substrate 80k-h endoplasmic reticulum-calcium ions store |
| title | Epilepsy protein myoclonin1 interacts with inositol 1,4,5-trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulum |
| title_full | Epilepsy protein myoclonin1 interacts with inositol 1,4,5-trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulum |
| title_fullStr | Epilepsy protein myoclonin1 interacts with inositol 1,4,5-trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulum |
| title_full_unstemmed | Epilepsy protein myoclonin1 interacts with inositol 1,4,5-trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulum |
| title_short | Epilepsy protein myoclonin1 interacts with inositol 1,4,5-trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulum |
| title_sort | epilepsy protein myoclonin1 interacts with inositol 1 4 5 trisphosphate receptor and reduces calcium ions stored in endoplasmic reticulum |
| topic | efhc1 myoclonin1 juvenile myoclonic epilepsy inositol 1 4 5-trisphosphate receptor protein kinase c substrate 80k-h endoplasmic reticulum-calcium ions store |
| url | https://www.explorationpub.com/uploads/Article/A100699/100699.pdf |
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