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Gao Z, Lv J, Tong TT, Zhang K, Han YX, Zhao Y, Shen MM, Liu Y, Ban T, Sun Y. Role of the transient receptor potential melastatin 4 in inhibition effect of arsenic trioxide on the tumor biological features of colorectal cancer cell. PeerJ 2024; 12:e17559. [PMID: 38854798 PMCID: PMC11160432 DOI: 10.7717/peerj.17559] [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: 04/16/2024] [Accepted: 05/21/2024] [Indexed: 06/11/2024] Open
Abstract
Background To investigate the effects of arsenic trioxide (ATO) on human colorectal cancer cells (HCT116) growth and the role of transient receptor potential melastatin 4 (TRPM4) channel in this process. Methods The viability of HCT116 cells was assessed using the CCK-8 assay. Western blot analysis was employed to examine the protein expression of TRPM4. The apoptosis of HCT116 cells was determined using TUNEL and Flow cytometry. Cell migration was assessed through the cell scratch recovery assay and Transwell cell migration assay. Additionally, Transwell cell invasion assay was performed to determine the invasion ability of HCT116 cells. Results ATO suppressed the viability of HCT116 cells in a dose-dependent manner, accompanied by a decline in cell migration and invasion, and an increase in apoptosis. 9-phenanthroline (9-Ph), a specific inhibitor of TRPM4, abrogated the ATO-induced upregulation of TRPM4 expression. Additionally, blocking TRPM4 reversed the effects of ATO on HCT116 cells proliferation, including restoration of cell viability, migration and invasion, as well as the inhibition of apoptosis. Conclusion ATO inhibits CRC cell growth by inducing TRPM4 expression, our findings indicate that ATO is a promising therapeutic strategy and TRPM4 may be a novel target for the treatment of CRC.
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Affiliation(s)
- Zhan Gao
- General Medical Department, Heilongjiang Provincial Hospital, Harbin, Heilongjiang, China
| | - Jing Lv
- Department of Pediatric Dentistry, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Ting-Ting Tong
- Department of General Surgery, The Fourth Affiliated Hospital of Harbin Medical University, and Department of Pharmacology (State Key Labratoray -Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, Heilongjiang, China
| | - Kai Zhang
- Department of General Surgery, The Fourth Affiliated Hospital of Harbin Medical University, and Department of Pharmacology (State Key Labratoray -Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, Heilongjiang, China
| | - Yu-Xuan Han
- Department of General Surgery, The Fourth Affiliated Hospital of Harbin Medical University, and Department of Pharmacology (State Key Labratoray -Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, Heilongjiang, China
| | - Yu Zhao
- Department of General Surgery, The Fourth Affiliated Hospital of Harbin Medical University, and Department of Pharmacology (State Key Labratoray -Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, Heilongjiang, China
| | - Mei-Mei Shen
- Department of General Surgery, The Fourth Affiliated Hospital of Harbin Medical University, and Department of Pharmacology (State Key Labratoray -Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, Heilongjiang, China
| | - Yang Liu
- Department of General Surgery, The Fourth Affiliated Hospital of Harbin Medical University, and Department of Pharmacology (State Key Labratoray -Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, Heilongjiang, China
| | - Tao Ban
- Department of General Surgery, The Fourth Affiliated Hospital of Harbin Medical University, and Department of Pharmacology (State Key Labratoray -Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, Heilongjiang, China
- Heilongjiang Academy of Medical Sciences, Harbin, Heilongjiang, China
| | - Yu Sun
- Harbin Medical University Science Park, Harbin Medical University, Harbin, Heilongjiang, China
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Huffer K, Oskoui EV, Swartz KJ. Conservation of the cooling agent binding pocket within the TRPM subfamily. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.595003. [PMID: 38826484 PMCID: PMC11142142 DOI: 10.1101/2024.05.20.595003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Transient Receptor Potential (TRP) channels are a large and diverse family of tetrameric cation selective channels that are activated by many different types of stimuli, including noxious heat or cold, organic ligands such as vanilloids or cooling agents, or intracellular Ca2+. Structures available for all subtypes of TRP channels reveal that the transmembrane domains are closely related despite their unique sensitivity to activating stimuli. Here we use computational and electrophysiological approaches to explore the conservation of the cooling agent binding pocket identified within the S1-S4 domain of the Melastatin subfamily member TRPM8, the mammalian sensor of noxious cold, with other TRPM channel subtypes. We find that a subset of TRPM channels, including TRPM2, TRPM4 and TRPM5, contain well-conserved cooling agent binding pockets. We then show how the cooling agent icilin modulates activation of TRPM4 to intracellular Ca2+, enhancing the sensitivity of the channel to Ca2+ and diminishing outward-rectification to promote opening at negative voltages. Mutations known to promote or diminish activation of TRPM8 by icilin similarly alter activation of TRPM4 by the cooling agent, suggesting that icilin binds to the cooling agent binding pocket to promote opening of the channel. These findings demonstrate that TRPM4 and TRPM8 channels share related cooling agent binding pockets that are allosterically coupled to opening of the pore.
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Affiliation(s)
- Kate Huffer
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | | | - Kenton J. Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
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Xue Y, Tong T, Zhang Y, Huang H, Zhao L, Lv H, Xiong L, Zhang K, Han Y, Fu Y, Wang Y, Huo R, Wang N, Ban T. miR-133a-3p/TRPM4 axis improves palmitic acid induced vascular endothelial injury. Front Pharmacol 2024; 14:1340247. [PMID: 38269270 PMCID: PMC10806017 DOI: 10.3389/fphar.2023.1340247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 12/14/2023] [Indexed: 01/26/2024] Open
Abstract
Background: Vascular endothelial injury is a contributing factor to the development of atherosclerosis and the resulting cardiovascular diseases. One particular factor involved in endothelial cell apoptosis and atherosclerosis is palmitic acid (PA), which is a long-chain saturated fatty acid. In addition, transient receptor potential melastatin 4 (TRPM4), a non-selective cation channel, plays a significant role in endothelial dysfunction caused by various factors related to cardiovascular diseases. Despite this, the specific role and mechanisms of TRPM4 in atherosclerosis have not been fully understood. Methods: The protein and mRNA expressions of TRPM4, apoptosis - and inflammation-related factors were measured after PA treatment. The effect of TRPM4 knockout on the protein and mRNA expression of apoptosis and inflammation-related factors was detected. The changes of intracellular Ca2+, mitochondrial membrane potential, and reactive oxygen species were detected by Fluo-4 AM, JC-1, and DCFH-DA probes, respectively. To confirm the binding of miR-133a-3p to TRPM4, a dual luciferase reporter gene assay was conducted. Finally, the effects of miR-133a-3p and TRPM4 on intracellular Ca2+, mitochondrial membrane potential, and reactive oxygen species were examined. Results: Following PA treatment, the expression of TRPM4 increases, leading to calcium overload in endothelial cells. This calcium influx causes the assemblage of Bcl-2, resulting in the opening of mitochondrial calcium channels and mitochondrial damage, ultimately triggering apoptosis. Throughout this process, the mRNA and protein levels of IL-1β, ICAM-1, and VCAM1 significantly increase. Database screenings and luciferase assays have shown that miR-133a-3p preferentially binds to the 3'UTR region of TRPM4 mRNA, suppressing TRPM4 expression. During PA-induced endothelial injury, miR-133a-3p is significantly decreased, but overexpression of miR-133a-3p can attenuate the progression of endothelial injury. On the other hand, overexpression of TRPM4 counteracts the aforementioned changes. Conclusion: TRPM4 participates in vascular endothelial injury caused by PA. Therefore, targeting TRPM4 or miR-133a-3p may offer a novel pharmacological approach to preventing endothelial injury.
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Affiliation(s)
- Yadong Xue
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Tingting Tong
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yuyao Zhang
- Department of Anatomy, School of Basic Medical Sciences, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Haijun Huang
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Ling Zhao
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Hongzhao Lv
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Lingzhao Xiong
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Kai Zhang
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yuxuan Han
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yuyang Fu
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yongzhen Wang
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Rong Huo
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Ning Wang
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
| | - Tao Ban
- Department of Pharmacology (The Key Laboratory of Cardiovascular Research, Ministry of Education, State Key Laboratory of Frigid Zone Cardiovascular Diseases, Ministry of Science and Technology) at College of Pharmacy, Harbin Medical University, Harbin, China
- Department of General Surgery, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China
- Heilongjiang Academy of Medical Sciences, Harbin, China
- National-Local Joint Engineering Laboratory of Drug Research and Development of Cardio-Cerebrovascular Diseases in Frigid Zone, The National Development and Reform Commission, Harbin, China
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Takahashi Y, Fukuda H, Hayakawa A, Sano R, Kubo R, Kawabata-Iwakawa R, Nakajima T, Ishige T, Tokue H, Asano K, Seki T, Hsiao YY, Ishizawa F, Takei H, Kominato Y. Postmortem genetic analysis of 17 sudden cardiac deaths identified nonsense and frameshift variants in two cases of arrhythmogenic cardiomyopathy. Int J Legal Med 2023; 137:1927-1937. [PMID: 37328711 DOI: 10.1007/s00414-023-03037-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/01/2023] [Indexed: 06/18/2023]
Abstract
Sudden death, or unexpected natural death of a healthy individual, is a serious problem in all nations. Sudden cardiac death (SCD) mainly due to ischemic heart diseases is the top cause of sudden death. However, there are pathophysiological conditions, referred to as sudden arrhythmic death syndrome, in which no apparent lesion can be identified even after complete conventional or ordinary autopsy. While postmortem genetic analyses have accumulated evidence about underlying genetic abnormality in such cases, the precise relationships between genetic background and the phenotype have been largely elusive. In this study, a retrospective investigation of 17 autopsy cases in which lethal arrhythmia was suspected to be the cause of death was carried out. Genetic analysis focusing on 72 genes reported to be associated with cardiac dysfunctions was performed, in combination with detailed histopathological and postmortem imaging examination, and a family study. As a result, in two cases of suspected arrhythmogenic cardiomyopathy (ACM), we found a nonsense variant in PKP2 and frameshift variant in TRPM4 gene. In contrast, the other 15 cases showed no morphological changes in the heart despite the presence of a frameshift variant and several missense variants, leaving the clinical significance of these variants obscure. The findings of the present study suggest that nonsense and frameshift variants could be involved in the morphological abnormality in cases of SCD due to ACM, while missense variants alone rarely contribute to massive structural changes in the heart.
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Affiliation(s)
- Yoichiro Takahashi
- Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan.
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
| | - Haruki Fukuda
- Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Akira Hayakawa
- Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Rie Sano
- Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Rieko Kubo
- Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Reika Kawabata-Iwakawa
- Division of Integrated Oncology Research, Gunma University Initiative for Advanced Research, Gunma University, Maebashi, Japan
| | - Tadashi Nakajima
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Takashi Ishige
- Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Hiroyuki Tokue
- Department of Diagnostic Radiology & Nuclear Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Kazuya Asano
- Department of Radiology, Gunma University Hospital, Maebashi, Japan
| | - Tomohiro Seki
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Yi-Yang Hsiao
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Fujio Ishizawa
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Hiroyuki Takei
- Department of Radiology, Gunma University Hospital, Maebashi, Japan
- Faculty of Health Sciences, Tsukuba International University, Tsuchiura, Japan
| | - Yoshihiko Kominato
- Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
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Hu Y, Cang J, Hiraishi K, Fujita T, Inoue R. The Role of TRPM4 in Cardiac Electrophysiology and Arrhythmogenesis. Int J Mol Sci 2023; 24:11798. [PMID: 37511555 PMCID: PMC10380800 DOI: 10.3390/ijms241411798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/20/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
The transient receptor potential melastatin 4 (TRPM4) channel is a non-selective cation channel that activates in response to increased intracellular Ca2+ levels but does not allow Ca2+ to pass through directly. It plays a crucial role in regulating diverse cellular functions associated with intracellular Ca2+ homeostasis/dynamics. TRPM4 is widely expressed in the heart and is involved in various physiological and pathological processes therein. Specifically, it has a significant impact on the electrical activity of cardiomyocytes by depolarizing the membrane, presumably via Na+ loading. The TRPM4 channel likely contributes to the development of cardiac arrhythmias associated with specific genetic backgrounds and cardiac remodeling. This short review aims to overview what is known so far about the TRPM4 channel in cardiac electrophysiology and arrhythmogenesis, highlighting its potential as a novel therapeutic target to effectively prevent and treat cardiac arrhythmias.
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Affiliation(s)
- Yaopeng Hu
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
| | - Jiehui Cang
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
| | - Keizo Hiraishi
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
| | - Takayuki Fujita
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
| | - Ryuji Inoue
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
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TRPM4 Participates in Irradiation-Induced Aortic Valve Remodeling in Mice. Cancers (Basel) 2022; 14:cancers14184477. [PMID: 36139640 PMCID: PMC9497207 DOI: 10.3390/cancers14184477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Despite its benefit in cancer treatment, thoracic irradiation can induce aortic valve stenosis with fibrosis and calcification. The TRPM4 cation channel is known to participate in cellular remodeling including the transition of cardiac fibroblasts to myofibroblasts, similar to that observed during aortic valve stenosis. This study evaluates if TRPM4 is involved in irradiation-induced aortic valve damage. The aortic valve of mice was targeted by irradiation. Cardiac echography 5 months after treatment revealed an increase in aortic jet velocity, indicating stenosis. This was not observed in non-treated animals. Histological analysis revealed an increase in valvular cusp surface associated with fibrosis which was not observed in non-treated animals. The experiments were reproduced on mice after Trpm4 gene disruption. In these animals, irradiation did not induce valvular remodeling. It indicates that TRPM4 influences irradiation-induced aortic valve damage and thus could be a target to prevent such side effects of irradiation. Abstract Thoracic radiotherapy can lead to cardiac remodeling including valvular stenosis due to fibrosis and calcification. The monovalent non-selective cation channel TRPM4 is known to be involved in calcium handling and to participate in fibroblast transition to myofibroblasts, a phenomenon observed during aortic valve stenosis. The goal of this study was to evaluate if TRPM4 is involved in irradiation-induced aortic valve damage. Four-month-old Trpm4+/+ and Trpm4−/− mice received 10 Gy irradiation at the aortic valve. Cardiac parameters were evaluated by echography until 5 months post-irradiation, then hearts were collected for morphological and histological assessments. At the onset of the protocol, Trpm4+/+ and Trpm4−/− mice exhibited similar maximal aortic valve jet velocity and mean pressure gradient. Five months after irradiation, Trpm4+/+ mice exhibited a significant increase in those parameters, compared to the untreated animals while no variation was detected in Trpm4−/− mice. Morphological analysis revealed that irradiated Trpm4+/+ mice exhibited a 53% significant increase in the aortic valve cusp surface while no significant variation was observed in Trpm4−/− animals. Collagen staining revealed aortic valve fibrosis in irradiated Trpm4+/+ mice but not in irradiated Trpm4−/− animals. It indicates that TRPM4 influences irradiation-induced valvular remodeling.
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A Novel Role of the TRPM4 Ion Channel in Exocytosis. Cells 2022; 11:cells11111793. [PMID: 35681487 PMCID: PMC9180413 DOI: 10.3390/cells11111793] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/20/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022] Open
Abstract
Under physiological conditions, the widely expressed calcium-activated TRPM4 channel conducts sodium into cells. This sodium influx depolarizes the plasma membrane and reduces the driving force for calcium entry. The aberrant expression or function of TRPM4 has been reported in various diseases, including different types of cancer. TRPM4 is mainly localized in the plasma membrane, but it is also found in intracellular vesicles, which can undergo exocytosis. In this study, we show that calcium-induced exocytosis in the colorectal cancer cell line HCT116 is dependent on TRPM4. In addition, the findings from some studies of prostate cancer cell lines suggest a more general role of TRPM4 in calcium-induced exocytosis in cancer cells. Furthermore, calcium-induced exocytosis depends on TRPM4 ion conductivity. Additionally, an increase in intracellular calcium results in the delivery of TRPM4 to the plasma membrane. This process also depends on TRPM4 ion conductivity. TRPM4-dependent exocytosis and the delivery of TRPM4 to the plasma membrane are mediated by SNARE proteins. Finally, we provide evidence that calcium-induced exocytosis depends on TRPM4 ion conductivity, not within the plasma membrane, but rather in TRPM4-containing vesicles.
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