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Mamaeva D, Jazouli Z, DiFrancesco ML, Erkilic N, Dubois G, Hilaire C, Meunier I, Boukhaddaoui H, Kalatzis V. Novel roles for voltage-gated T-type Ca 2+ and ClC-2 channels in phagocytosis and angiogenic factor balance identified in human iPSC-derived RPE. FASEB J 2021; 35:e21406. [PMID: 33724552 DOI: 10.1096/fj.202002754r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/13/2021] [Accepted: 01/19/2021] [Indexed: 01/26/2023]
Abstract
Human-induced pluripotent stem cell (hiPSC)-derived retinal pigment epithelium (RPE) is a powerful tool for pathophysiological studies and preclinical therapeutic screening, as well as a source for clinical cell transplantation. Thus, it must be validated for maturity and functionality to ensure correct data readouts and clinical safety. Previous studies have validated hiPSC-derived RPE as morphologically characteristic of the tissue in the human eye. However, information concerning the expression and functionality of ion channels is still limited. We screened hiPSC-derived RPE for the polarized expression of a panel of L-type (CaV 1.1, CaV 1.3) and T-type (CaV 3.1, CaV 3.3) Ca2+ channels, K+ channels (Maxi-K, Kir4.1, Kir7.1), and the Cl- channel ClC-2 known to be expressed in native RPE. We also tested the roles of these channels in key RPE functions using specific inhibitors. In addition to confirming the native expression profiles and function of certain channels, such as L-type Ca2+ channels, we show for the first time that T-type Ca2+ channels play a role in both phagocytosis and vascular endothelial growth factor (VEGF) secretion. Moreover, we demonstrate that Maxi-K and Kir7.1 channels are involved in the polarized secretion of VEGF and pigment epithelium-derived factor (PEDF). Furthermore, we show a novel localization for ClC-2 channel on the apical side of hiPSC-derived RPE, with an overexpression at the level of fluid-filled domes, and demonstrate that it plays an important role in phagocytosis, as well as VEGF and PEDF secretion. Taken together, hiPSC-derived RPE is a powerful model for advancing fundamental knowledge of RPE functions.
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Affiliation(s)
- Daria Mamaeva
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Zhour Jazouli
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Mattia L DiFrancesco
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Nejla Erkilic
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France.,National Reference Centre for Inherited Sensory Diseases, Montpellier University, CHU, Montpellier, France
| | - Gregor Dubois
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Cecile Hilaire
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Isabelle Meunier
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France.,National Reference Centre for Inherited Sensory Diseases, Montpellier University, CHU, Montpellier, France
| | - Hassan Boukhaddaoui
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Vasiliki Kalatzis
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
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2
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Abstract
BACKGROUND Pregabalin is a gamma-aminobutyric acid analog that binds to the α2-δ subunits of the pre-synaptic voltage-dependent calcium channels of nerves with a high affinity and selectivity. In this study, the retinal teratogenic potential of pregabalin was investigated in a chick embryo model. MATERIALS AND METHODS Fertilised chicken eggs were divided into groups for administration with different doses of pregabalin. All eggs were opened on the 10th day of incubation. The embryos were dissected and the effects of pregabalin on the retina were investigated histopathologically, morphometrically, and immunohistochemically (Caspase-3). RESULTS There was no statistically significant difference between the low dose pregabalin, control, or vehicle control groups in terms of the number of retina layers and retinal thickness. Medium and high dose pregabalin caused a statistically significant decrease in the number of retina layers, as well as sensory retinal and pigment epithelium layer thicknesses. The outer nuclear and outer plexiform layer did not form in the group administered a medium dose. Similarly, the outer nuclear, outer plexiform, inner nuclear, and inner plexiform layer did not form in the high-dose group. No statistically significant difference was observed between the groups in terms of cellular damage and Caspase-3 expression. CONCLUSION The use of pregabalin during pregnancy compromises retinal development in a dose-dependent manner. The use of pregabalin in pregnancy causes the aforementioned defects in this system and it may have developmental effects that needs to be further evaluated.
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Affiliation(s)
- Ilke Evrim Secinti
- Department of Pathology, School of Medicine, Hatay Mustafa Kemal University, Hatay, Turkey
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Korkka I, Viheriälä T, Juuti-Uusitalo K, Uusitalo-Järvinen H, Skottman H, Hyttinen J, Nymark S. Functional Voltage-Gated Calcium Channels Are Present in Human Embryonic Stem Cell-Derived Retinal Pigment Epithelium. Stem Cells Transl Med 2018; 8:179-193. [PMID: 30394009 PMCID: PMC6344904 DOI: 10.1002/sctm.18-0026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 08/24/2018] [Accepted: 09/07/2018] [Indexed: 11/25/2022] Open
Abstract
Retinal pigment epithelium (RPE) performs important functions for the maintenance of photoreceptors and vision. Malfunctions within the RPE are implicated in several retinal diseases for which transplantations of stem cell‐derived RPE are promising treatment options. Their success, however, is largely dependent on the functionality of the transplanted cells. This requires correct cellular physiology, which is highly influenced by the various ion channels of RPE, including voltage‐gated Ca2+ (CaV) channels. This study investigated the localization and functionality of CaV channels in human embryonic stem cell (hESC)‐derived RPE. Whole‐cell patch‐clamp recordings from these cells revealed slowly inactivating L‐type currents comparable to freshly isolated mouse RPE. Some hESC‐RPE cells also carried fast transient T‐type resembling currents. These findings were confirmed by immunostainings from both hESC‐ and mouse RPE that showed the presence of the L‐type Ca2+ channels CaV1.2 and CaV1.3 as well as the T‐type Ca2+ channels CaV3.1 and CaV3.2. The localization of the major subtype, CaV1.3, changed during hESC‐RPE maturation co‐localizing with pericentrin to the base of the primary cilium before reaching more homogeneous membrane localization comparable to mouse RPE. Based on functional assessment, the L‐type Ca2+ channels participated in the regulation of vascular endothelial growth factor secretion as well as in the phagocytosis of photoreceptor outer segments in hESC‐RPE. Overall, this study demonstrates that a functional machinery of voltage‐gated Ca2+ channels is present in mature hESC‐RPE, which is promising for the success of transplantation therapies. stem cells translational medicine2019;8:179&15
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Affiliation(s)
- Iina Korkka
- Faculty of Biomedical Sciences and Engineering, BioMediTech, Tampere University of Technology, Tampere, Finland
| | - Taina Viheriälä
- Faculty of Biomedical Sciences and Engineering, BioMediTech, Tampere University of Technology, Tampere, Finland.,Faculty of Medicine and Life Sciences, BioMediTech, University of Tampere, Tampere, Finland
| | - Kati Juuti-Uusitalo
- Faculty of Medicine and Life Sciences, BioMediTech, University of Tampere, Tampere, Finland
| | - Hannele Uusitalo-Järvinen
- Eye Centre, Tampere University Hospital, Tampere, Finland.,Faculty of Medicine and Life Sciences, Department of Ophthalmology, University of Tampere, Tampere, Finland
| | - Heli Skottman
- Faculty of Medicine and Life Sciences, BioMediTech, University of Tampere, Tampere, Finland
| | - Jari Hyttinen
- Faculty of Biomedical Sciences and Engineering, BioMediTech, Tampere University of Technology, Tampere, Finland
| | - Soile Nymark
- Faculty of Biomedical Sciences and Engineering, BioMediTech, Tampere University of Technology, Tampere, Finland
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Thrombin-Induced Calpain Activation Promotes Protease-Activated Receptor 1 Internalization. Int J Cell Biol 2017; 2017:1908310. [PMID: 29250115 PMCID: PMC5700505 DOI: 10.1155/2017/1908310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 10/02/2017] [Accepted: 10/15/2017] [Indexed: 12/19/2022] Open
Abstract
The serine protease thrombin activates Protease-Activated Receptors (PARs), a family of G-protein-coupled receptors (GPCRs) activated by the proteolytic cleavage of their extracellular N-terminal domain. Four members of this family have been identified: PAR1–4. The activation of Protease-Activated Receptor 1(PAR1), the prototype of this receptor family, leads to an increase in intracellular Ca+2 concentration ([Ca+2]i) mediated by Gq11α coupling and phospholipase C (PLC) activation. We have previously shown that the stimulation of PAR1 by thrombin promotes intracellular signaling leading to RPE cell transformation, proliferation, and migration which characterize fibroproliferative eye diseases leading to blindness. Within this context, the elucidation of the mechanisms involved in PAR1 inactivation is of utmost importance. Due to the irreversible nature of PAR1 activation, its inactivation must be efficiently regulated in order to terminate signaling. Using ARPE-19 human RPE cell line, we characterized thrombin-induced [Ca+2]i increase and demonstrated the calcium-dependent activation of μ-calpain mediated by PAR1. Calpains are a family of calcium-activated cysteine proteases involved in multiple cellular processes including the internalization of membrane proteins through clathrin-coated vesicles. We demonstrated that PAR1-induced calpain activation results in the degradation of α-spectrin by calpain, essential for receptor endocytosis, and the consequent decrease in PAR1 membrane expression. Collectively, the present results identify a novel μ-calpain-dependent mechanism for PAR1 inactivation following exposure to thrombin.
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Seitter H, Koschak A. Relevance of tissue specific subunit expression in channelopathies. Neuropharmacology 2017; 132:58-70. [PMID: 28669898 DOI: 10.1016/j.neuropharm.2017.06.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 06/22/2017] [Accepted: 06/28/2017] [Indexed: 12/27/2022]
Abstract
Channelopathies are a diverse group of human disorders that are caused by mutations in genes coding for ion channels or channel-regulating proteins. Several dozen channelopathies have been identified that involve both non-excitable cells as well as electrically active tissues like brain, skeletal and smooth muscle or the heart. In this review, we start out from the general question which ion channel genes are expressed tissue-selectively. We mined the human gene expression database Human Protein Atlas (HPA) for tissue-enriched ion channel genes and found 85 genes belonging to the ion channel families. Most of these genes were enriched in brain, testis and muscle and a complete list of the enriched ion channel genes is provided. We further focused on the tissue distribution of voltage-gated calcium channel (VGCC) genes including different brain areas and the retina based on the human gene expression from the FANTOM5 dataset. The expression data is complemented by an overview of the tissue-dependent aspects of L-type calcium channel (LTCC) function, dysfunction and pharmacology, as well as of their splice variants. Finally, we focus on the pathology of tissue-restricted LTCC channelopathies and their treatment options. This article is part of the Special Issue entitled 'Channelopathies.'
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Affiliation(s)
- Hartwig Seitter
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, Innrain 80-82/III, 6020 Innsbruck, Austria
| | - Alexandra Koschak
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, Innrain 80-82/III, 6020 Innsbruck, Austria.
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6
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Reichhart N, Markowski M, Ishiyama S, Wagner A, Crespo-Garcia S, Schorb T, Ramalho JS, Milenkovic VM, Föckler R, Seabra MC, Strauß O. Rab27a GTPase modulates L-type Ca2+ channel function via interaction with the II-III linker of CaV1.3 subunit. Cell Signal 2015; 27:2231-40. [PMID: 26235199 DOI: 10.1016/j.cellsig.2015.07.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/28/2015] [Indexed: 12/31/2022]
Abstract
In a variety of cells, secretory processes require the activation of both Rab27a and L-type channels of the Ca(V)1.3 subtype. In the retinal pigment epithelium (RPE), Rab27a and Ca(V)1.3 channels regulate growth-factor secretion towards its basolateral side. Analysis of murine retina sections revealed a co-localization of both Rab27a and Ca(V)1.3 at the basolateral membrane of the RPE. Heterologously expressed Ca(V)1.3/β3/α2δ1 channels showed negatively shifted voltage-dependence and decreased current density of about 70% when co-expressed with Rab27a. However, co-localization analysis using α(5)β(1) integrin as a membrane marker revealed that Rab27a co-expression reduced the surface expression of Ca(V)1.3 only about 10%. Physical binding of heterologously expressed Rab27a with Ca(V)1.3 channels was shown by co-localization in immunocytochemistry as well as co-immunoprecipitation which was abolished after deletion of a MyRIP-homologous amino acid sequence at the II-III linker of the Ca(V)1.3 subunit. Rab27a over-expression in ARPE-19 cells positively shifted the voltage dependence, decreased current density of endogenous Ca(V)1.3 channels and reduced VEGF-A secretion. We show the first evidence of a direct functional modulation of an ion channel by Rab27a suggesting a new mechanism of Rab and ion channel interaction in the control of VEGF-A secretion in the RPE.
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Affiliation(s)
- Nadine Reichhart
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Magdalena Markowski
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Shimpei Ishiyama
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Andrea Wagner
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Sergio Crespo-Garcia
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Talitha Schorb
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - José S Ramalho
- CEDOC, Faculdade de Ciências Médicas (FCM), Universidade Nova de Lisboa, Lisbon, Portugal
| | - Vladimir M Milenkovic
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Department of Psychiatry and Psychotherapy, Molecular Neuroscience, University of Regensburg, Germany
| | - Renate Föckler
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Miguel C Seabra
- CEDOC, Faculdade de Ciências Médicas (FCM), Universidade Nova de Lisboa, Lisbon, Portugal
| | - Olaf Strauß
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany.
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Ophthalmological assessment of cannabis-induced persisting perception disorder: is there a direct retinal effect? Doc Ophthalmol 2015; 130:121-30. [PMID: 25612939 DOI: 10.1007/s10633-015-9481-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 01/06/2015] [Indexed: 12/22/2022]
Abstract
PURPOSE Cannabis is a psychotomimetic agent that induces impairment of sensory perception. We present detailed clinical and electrophysiological data of patients with hallucinogen persisting perception disorder (HPPD) after marijuana consumption. METHODS A HPPD patient and four heavy cannabis smokers with no visual disturbances (controls) underwent complete ophthalmological examination including psychophysical tests (visual acuity, color vision, visual field, and dark adaptation) and detailed electrophysiological examinations, including extended Ganzfeld ERG, multifocal ERG, and electrooculography (EOG). Furthermore, electrically evoked phosphene thresholds (EPTs) were measured to further evaluate retinal function. RESULTS Ophthalmological and most electrophysiological examinations were within normal limits for the HPPD patient and for all control subjects. Interestingly, EOG results of the HPPD patient showed a slightly reduced fast oscillation ratio, diminished standing potentials of the slow oscillations, and a light peak within normal range resulting in higher Arden ratios. The EPTs of the patient were reduced, in particular for pulses with long durations (50 ms) causing visual sensations even at lowest possible currents of the neurostimulator. The control subjects did not reveal such alterations. CONCLUSIONS Our findings suggest a direct effect of cannabinoids on the retina and retinal pigment epithelium function, which may be involved in disturbances of the visual function experienced after drug consumption. The observations presented here may contribute to the elucidation of the detailed mechanism. Furthermore, EOG and EPT measurements may be useful tools to demonstrate long-term retinal alterations in cannabis-induced HPPD in patients.
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8
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Ion channels and transporters of the retinal pigment epithelium. Exp Eye Res 2014; 126:27-37. [DOI: 10.1016/j.exer.2014.05.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 05/02/2014] [Accepted: 05/12/2014] [Indexed: 12/19/2022]
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9
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CaV1.3 L-type channels, maxiK Ca2+-dependent K+ channels and bestrophin-1 regulate rhythmic photoreceptor outer segment phagocytosis by retinal pigment epithelial cells. Cell Signal 2014; 26:968-78. [DOI: 10.1016/j.cellsig.2013.12.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 12/31/2013] [Indexed: 11/20/2022]
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Das A, Pushparaj C, Bahí N, Sorolla A, Herreros J, Pamplona R, Vilella R, Matias-Guiu X, Martí RM, Cantí C. Functional expression of voltage-gated calcium channels in human melanoma. Pigment Cell Melanoma Res 2012; 25:200-12. [PMID: 22260517 DOI: 10.1111/j.1755-148x.2012.00978.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The expression of voltage-gated calcium channels (VGCCs) has not been reported previously in melanoma cells in spite of increasing evidence of a role of VGCCs in tumorigenesis and tumour progression. To address this issue we have performed an extensive RT-PCR analysis of VGCC expression in human melanocytes and a range of melanoma cell lines and biopsies. In addition, we have tested the functional expression of these channels using Ca(2+) imaging techniques and examined their relevance for the viability and proliferation of the melanoma cells. Our results show that control melanocytes and melanoma cells express channel isoforms belonging to the Ca(v) 1 and Ca(v) 2 gene families. Importantly, the expression of low voltage-activated Ca(v) 3 (T-type) channels is restricted to melanoma. We have confirmed the function of T-type channels as mediators of constitutive Ca(2+) influx in melanoma cells. Finally, pharmacological and gene silencing approaches demonstrate a role for T-type channels in melanoma viability and proliferation. These results encourage the analysis of T-type VGCCs as targets for therapeutic intervention in melanoma tumorigenesis and/or tumour progression.
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Affiliation(s)
- A Das
- Laboratori d'Investigació, University of Lleida-IRBLleida, Lerida, Spain
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Effect of bestrophin-1 on L-type Ca2+ channel activity depends on the Ca2+ channel beta-subunit. Exp Eye Res 2010; 91:630-9. [DOI: 10.1016/j.exer.2010.08.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2010] [Revised: 07/02/2010] [Accepted: 08/02/2010] [Indexed: 11/17/2022]
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The best disease-linked Cl- channel hBest1 regulates Ca V 1 (L-type) Ca2+ channels via src-homology-binding domains. J Neurosci 2008; 28:5660-70. [PMID: 18509027 DOI: 10.1523/jneurosci.0065-08.2008] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mutations in the bestrophin-1 (Best1) gene are linked to several kinds of macular degeneration in both humans and dogs. Although bestrophins have been shown clearly to be Cl(-) ion channels, it is controversial whether Cl(-) channel dysfunction can explain the diseases. It has been suggested that bestrophins are multifunctional proteins: they may regulate voltage-gated Ca(2+) channels in addition to functioning as Cl(-) channels. Here, we show that human Best1 gene (hBest1) differentially modulates Ca(V)1.3 (L-type) voltage-gated Ca(2+) channels through association with the Ca(V)beta subunit. In transfected human embryonic kidney 293 cells, hBest1 inhibited Ca(V)1.3. Inhibition of Ca(V)1.3 was not observed in the absence of the beta subunit. Also, the hBest1 C terminus binds to Ca(V)beta subunits, suggesting that the effect of hBest1 was mediated by the Ca(V)beta subunit. The region of hBest1 responsible for the effect was localized to a region (amino acids 330-370) in the cytoplasmic C terminus that contains a predicted src-homology-binding domain that is not present in other bestrophin subtypes. Mutation of Pro(330) and Pro(334) abolished the effects of hBest1 on Ca(V)1.3. The effect was specific to hBest1; it was not observed with mouse Best1 (mBest1), mBest2, or mBest3. Wild-type hBest1 and the disease-causing mutants R92S, G299R, and D312N inhibited Ca(V) currents the same amount, whereas the A146K and G222E mutants were less effective. We propose that hBest1 regulates Ca(V) channels by interacting with the Ca(V)beta subunit and altering channel availability. Our findings reveal a novel function of bestrophin in regulation of Ca(V) channels and suggest a possible mechanism for the role of hBest1 in macular degeneration.
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