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Sakaji K, Ebrahimiazar S, Harigae Y, Ishibashi K, Sato T, Yoshikawa T, Atsumi GI, Sung CH, Saito M. MAST4 promotes primary ciliary resorption through phosphorylation of Tctex-1. Life Sci Alliance 2023; 6:e202301947. [PMID: 37726137 PMCID: PMC10509483 DOI: 10.26508/lsa.202301947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 08/27/2023] [Accepted: 08/28/2023] [Indexed: 09/21/2023] Open
Abstract
The primary cilium undergoes cell cycle-dependent assembly and disassembly. Dysregulated ciliary dynamics are associated with several pathological conditions called ciliopathies. Previous studies showed that the localization of phosphorylated Tctex-1 at Thr94 (T94) at the ciliary base critically regulates ciliary resorption by accelerating actin remodeling and ciliary pocket membrane endocytosis. Here, we show that microtubule-associated serine/threonine kinase family member 4 (MAST4) is localized at the primary cilium. Suppressing MAST4 blocks serum-induced ciliary resorption, and overexpressing MAST4 accelerates ciliary resorption. Tctex-1 binds to the kinase domain of MAST4, in which the R503 and D504 residues are key to MAST4-mediated ciliary resorption. The ciliary resorption and the ciliary base localization of phospho-(T94)Tctex-1 are blocked by the knockdown of MAST4 or the expression of the catalytic-inactive site-directed MAST4 mutants. Moreover, MAST4 is required for Cdc42 activation and Rab5-mediated periciliary membrane endocytosis during ciliary resorption. These results support that MAST4 is a novel kinase that regulates ciliary resorption by modulating the ciliary base localization of phospho-(T94)Tctex-1. MAST4 is a potential new target for treating ciliopathies causally by ciliary resorption defects.
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Affiliation(s)
- Kensuke Sakaji
- Department of Molecular Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Sara Ebrahimiazar
- Department of Molecular Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Developmental Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yasuhiro Harigae
- Department of Molecular Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kenichi Ishibashi
- https://ror.org/01gaw2478 Department of Molecular Physiology and Pathology, School of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Takeya Sato
- Department of Molecular Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Clinical Biology and Hormonal Regulation, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Takeo Yoshikawa
- Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Gen-Ichi Atsumi
- https://ror.org/01gaw2478 Department of Molecular Physiology and Pathology, School of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Ching-Hwa Sung
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY, USA
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY, USA
| | - Masaki Saito
- Department of Molecular Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
- https://ror.org/01gaw2478 Department of Molecular Physiology and Pathology, School of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
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Saito M, Hirano M, Izumi T, Mori Y, Ito K, Saitoh Y, Terada N, Sato T, Sukegawa J. Cytoskeletal Protein 4.1G Is Essential for the Primary Ciliogenesis and Osteoblast Differentiation in Bone Formation. Int J Mol Sci 2022; 23:ijms23042094. [PMID: 35216233 PMCID: PMC8878336 DOI: 10.3390/ijms23042094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/06/2022] [Accepted: 02/10/2022] [Indexed: 12/04/2022] Open
Abstract
The primary cilium is a hair-like immotile organelle with specific membrane receptors, including the receptor of Hedgehog signaling, smoothened. The cilium organized in preosteoblasts promotes differentiation of the cells into osteoblasts (osteoblast differentiation) by mediating Hedgehog signaling to achieve bone formation. Notably, 4.1G is a plasma membrane-associated cytoskeletal protein that plays essential roles in various tissues, including the peripheral nervous system, testis, and retina. However, its function in the bone remains unexplored. In this study, we identified 4.1G expression in the bone. We found that, in the 4.1G-knockout mice, calcium deposits and primary cilium formation were suppressed in the trabecular bone, which is preosteoblast-rich region of the newborn tibia, indicating that 4.1G is a prerequisite for osteoblast differentiation by organizing the primary cilia in preosteoblasts. Next, we found that the primary cilium was elongated in the differentiating mouse preosteoblast cell line MC3T3-E1, whereas the knockdown of 4.1G suppressed its elongation. Moreover, 4.1G-knockdown suppressed the induction of the cilia-mediated Hedgehog signaling and subsequent osteoblast differentiation. These results demonstrate a new regulatory mechanism of 4.1G in bone formation that promotes the primary ciliogenesis in the differentiating preosteoblasts and induction of cilia-mediated osteoblast differentiation, resulting in bone formation at the newborn stage.
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Affiliation(s)
- Masaki Saito
- Department of Molecular Pharmacology, Tohoku University School of Medicine, Sendai 980-8575, Japan; (M.H.); (T.I.); (T.S.)
- Correspondence: ; Tel.: +81-22-717-8207
| | - Marina Hirano
- Department of Molecular Pharmacology, Tohoku University School of Medicine, Sendai 980-8575, Japan; (M.H.); (T.I.); (T.S.)
- Department of Human Health and Nutrition, Shokei Gakuin University, Natori 981-1295, Japan;
| | - Tomohiro Izumi
- Department of Molecular Pharmacology, Tohoku University School of Medicine, Sendai 980-8575, Japan; (M.H.); (T.I.); (T.S.)
| | - Yu Mori
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan; (Y.M.); (K.I.)
| | - Kentaro Ito
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan; (Y.M.); (K.I.)
| | - Yurika Saitoh
- Center for Medical Education, Teikyo University of Science, Adachi-ku, Tokyo 120-0045, Japan;
| | - Nobuo Terada
- Health Science Division, Department of Medical Sciences, Shinshu University Graduate School of Medicine, Science and Technology, Matsumoto 390-0802, Japan;
| | - Takeya Sato
- Department of Molecular Pharmacology, Tohoku University School of Medicine, Sendai 980-8575, Japan; (M.H.); (T.I.); (T.S.)
| | - Jun Sukegawa
- Department of Human Health and Nutrition, Shokei Gakuin University, Natori 981-1295, Japan;
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