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Perumal N, Yurugi H, Dahm K, Rajalingam K, Grus FH, Pfeiffer N, Manicam C. Proteome landscape and interactome of voltage-gated potassium channel 1.6 (Kv1.6) of the murine ophthalmic artery and neuroretina. Int J Biol Macromol 2024; 257:128464. [PMID: 38043654 DOI: 10.1016/j.ijbiomac.2023.128464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/14/2023] [Accepted: 11/25/2023] [Indexed: 12/05/2023]
Abstract
The voltage-gated potassium channel 1.6 (Kv1.6) plays a vital role in ocular neurovascular beds and exerts its modulatory functions via interaction with other proteins. However, the interactome and their potential roles remain unknown. Here, the global proteome landscape of the ophthalmic artery (OA) and neuroretina was mapped, followed by the determination of Kv1.6 interactome and validation of its functionality and cellular localization. Microfluorimetric analysis of intracellular [K+] and Western blot validated the native functionality and cellular expression of the recombinant Kv1.6 channel protein. A total of 54, 9 and 28 Kv1.6-interacting proteins were identified in the mouse OA and, retina of mouse and rat, respectively. The Kv1.6-protein partners in the OA, namely actin cytoplasmic 2, alpha-2-macroglobulin and apolipoprotein A-I, were implicated in the maintenance of blood vessel integrity by regulating integrin-mediated adhesion to extracellular matrix and Ca2+ flux. Many retinal protein interactors, particularly the ADP/ATP translocase 2 and cytoskeleton protein tubulin, were involved in endoplasmic reticulum stress response and cell viability. Three common interactors were found in all samples comprising heat shock cognate 71 kDa protein, Ig heavy constant gamma 1 and Kv1.6 channel. This foremost in-depth investigation enriched and identified the elusive Kv1.6 channel and, elucidated its complex interactome.
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Affiliation(s)
- Natarajan Perumal
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Hajime Yurugi
- Cell Biology Unit, University Medical Centre of the Johannes Gutenberg University Mainz, Germany
| | - Katrin Dahm
- Cell Biology Unit, University Medical Centre of the Johannes Gutenberg University Mainz, Germany
| | - Krishnaraj Rajalingam
- Cell Biology Unit, University Medical Centre of the Johannes Gutenberg University Mainz, Germany
| | - Franz H Grus
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Caroline Manicam
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany.
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2
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Mei C, Yan P, Feng B, Mamat A, Wang J. The apple Ca 2+/H + exchanger MdCAX2L-2 functions positively in modulation of Ba 2+ tolerance. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108314. [PMID: 38184884 DOI: 10.1016/j.plaphy.2023.108314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/21/2023] [Accepted: 12/23/2023] [Indexed: 01/09/2024]
Abstract
Calcium is an essential element for plant growth and development, and it plays an important role in the responses of plants to abiotic stress. High concentrations of heavy metal ions in soil significantly affect the yield and quality of crops and pose human health threats when these ions accumulate in edible organs. The Ca2+/H+ exchanger (CAX) family is a class of transporters that mediate the transmembrane transport of both Ca2+ and metal ions, and they are widely involved in regulating plant growth and development and stress responses. Here, we cloned an AtCAX2 ortholog, MdCAX2L-2, from apple. It is constitutively expressed in various apple tissues and significantly induced by Ca2+ and Ba2+ treatments. The MdCAX2L-2 protein is located in the vacuolar membrane in both plant and yeast cells. Overexpression of MdCAX2L-2 enhanced the tolerance of the yeast mutant K667 to high concentrations of Ca2+ and Ba2+. In addition, the role of MdCAX2L-2 in modulating Ba2+ tolerance was identified using MdCAX2L-2-overexpressing transgenic Arabidopsis plants and apple calli. Comparison of growth phenotypes and stress-related physiological indexes under BaCl2 treatment indicated that MdCAX2L-2 could enhance the Ba2+ tolerance of plants by promoting Ba2+ compartmentalization into the vacuoles and eliminating excess ROS. Our results provide insights that will aid future studies examining the function of CAX proteins in regulating stress tolerance in fruit crops, as well as their underlying mechanisms.
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Affiliation(s)
- Chuang Mei
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Peng Yan
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Beibei Feng
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Aisajan Mamat
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Jixun Wang
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China.
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3
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Mao K, Yang J, Sun Y, Guo X, Qiu L, Mei Q, Li N, Ma F. MdbHLH160 is stabilized via reduced MdBT2-mediated degradation to promote MdSOD1 and MdDREB2A-like expression for apple drought tolerance. PLANT PHYSIOLOGY 2024; 194:1181-1203. [PMID: 37930306 DOI: 10.1093/plphys/kiad579] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 11/07/2023]
Abstract
Drought stress is a key environmental factor limiting the productivity, quality, and geographic distribution of crops worldwide. Abscisic acid (ABA) plays an important role in plant drought stress responses, but the molecular mechanisms remain unclear. Here, we report an ABA-responsive bHLH transcription factor, MdbHLH160, which promotes drought tolerance in Arabidopsis (Arabidopsis thaliana) and apple (Malus domestica). Under drought conditions, MdbHLH160 is directly bound to the MdSOD1 (superoxide dismutase 1) promoter and activated its transcription, thereby triggering reactive oxygen species (ROS) scavenging and enhancing apple drought tolerance. MdbHLH160 also promoted MdSOD1 enzyme activity and accumulation in the nucleus through direct protein interactions, thus inhibiting excessive nuclear ROS levels. Moreover, MdbHLH160 directly upregulated the expression of MdDREB2A-like, a DREB (dehydration-responsive element binding factor) family gene that promotes apple drought tolerance. Protein degradation and ubiquitination assays showed that drought and ABA treatment stabilized MdbHLH160. The BTB protein MdBT2 was identified as an MdbHLH160-interacting protein that promoted MdbHLH160 ubiquitination and degradation, and ABA treatment substantially inhibited this process. Overall, our findings provide insights into the molecular mechanisms of ABA-modulated drought tolerance at both the transcriptional and post-translational levels via the ABA-MdBT2-MdbHLH160-MdSOD1/MdDREB2A-like cascade.
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Affiliation(s)
- Ke Mao
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling 712100, Shaanxi, China
| | - Jie Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling 712100, Shaanxi, China
| | - Yunxia Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling 712100, Shaanxi, China
| | - Xin Guo
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling 712100, Shaanxi, China
| | - Lina Qiu
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling 712100, Shaanxi, China
| | - Quanlin Mei
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling 712100, Shaanxi, China
| | - Na Li
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling 712100, Shaanxi, China
| | - Fengwang Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling 712100, Shaanxi, China
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4
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Huang J, He J, Wang J, Li Y, Xu Z, Zhang L, Kang Y, Xue P. Calcium carbonate-actuated ion homeostasis perturbator for oxidative damage-augmented Ca 2+/Mg 2+ interference therapy. Biomaterials 2023; 302:122340. [PMID: 37774552 DOI: 10.1016/j.biomaterials.2023.122340] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/21/2023] [Accepted: 09/24/2023] [Indexed: 10/01/2023]
Abstract
Ion homeostasis distortion through exogenous overload or underload of intracellular ion species has become an arresting therapeutic approach against malignant tumor. Nevertheless, treatment outcomes of such ion interference are always compromised by the intrinsic ion homeostasis maintenance systems in cancer cells. Herein, an ion homeostasis perturbator (CTC) is facilely designed by co-encapsulation of carvacrol (CAR) and meso-tetra-(4-carboxyphenyl)porphine (TCPP) into pH-sensitive nano-CaCO3, aiming to disrupt the self-defense mechanism during the process of ion imbalance. Upon the endocytosis of CTC into tumor cells, lysosomal acidity can render the decomposition of CaCO3, resulting in the instant Ca2+ overload and CO2 generation in cytoplasm. Simultaneously, CaCO3 disintegration triggers the release of CAR and TCPP, which are devoted to TRPM7 inhibition and sonosensitization, respectively. The malfunction of TRPM7 can impede the influx of Mg2+ and allow unrestricted influx of Ca2+ based on the antagonism relationship between Mg2+ and Ca2+, leading to an aggravated Ca2+/Mg2+ dyshomeostasis through ion channel deactivation. In another aspect, US-triggered cavitation can be significantly enhanced by the presence of inert CO2 microbubbles, further amplifying the generation of reactive oxygen species. Such oxidative damage-augmented Ca2+/Mg2+ interference therapy effectively impairs the mitochondrial function of tumor, which may provide useful insights in cancer therapy.
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Affiliation(s)
- Jiansen Huang
- School of Materials and Energy, Southwest University, Chongqing, 400715, China
| | - Jie He
- School of Materials and Energy, Southwest University, Chongqing, 400715, China
| | - Jie Wang
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, 400715, China
| | - Yongcan Li
- School of Materials and Energy, Southwest University, Chongqing, 400715, China
| | - Zhigang Xu
- School of Materials and Energy, Southwest University, Chongqing, 400715, China
| | - Lei Zhang
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, 400715, China
| | - Yuejun Kang
- School of Materials and Energy, Southwest University, Chongqing, 400715, China
| | - Peng Xue
- School of Materials and Energy, Southwest University, Chongqing, 400715, China.
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5
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Wang Q, Qiao M, Song J. Characterization of Two Na +(K +, Li +)/H + Antiporters from Natronorubrum daqingense. Int J Mol Sci 2023; 24:10786. [PMID: 37445962 DOI: 10.3390/ijms241310786] [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: 05/16/2023] [Revised: 06/25/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
The Na+/H+ antiporter NhaC family protein is a kind of Na+/H+ exchanger from the ion transporter (IT) superfamily, which has mainly been identified in the halophilic bacteria of Bacillus. However, little is known about the Na+/H+ antiporter NhaC family of proteins in the extremely halophilic archaea. In this study, two Na+/H+ antiporter genes, nhaC1 and nhaC2, were screened from the genome of Natronorubrum daqingense based on the gene library and complementation of salt-sensitive Escherichia coli KNabc. A clone vector pUC18 containing nhaC1 or nhaC2 could make KNabc tolerate 0.6 M/0.7 M NaCl or 30 mM/40 mM LiCl and a pH of up to 8.5/9.5, respectively. Functional analysis shows that the Na+(K+, Li+)/H+ antiport activities of NhaC1 and NhaC2 are both pH-dependent in the range of pH 7.0-10.0, and the optimal pH is 9.5. Phylogenetic analysis shows that both NhaC1 and NhaC2 belong to the Na+/H+ antiporter NhaC family of proteins and are significantly distant from the identified NhaC proteins from Bacillus. In summary, we have identified two Na+(K+, Li+)/H+ antiporters from N. daqingense.
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Affiliation(s)
- Qi Wang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Mengwei Qiao
- School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Jinzhu Song
- School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
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6
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Hwang JY, Chung JJ. CatSper Calcium Channels: 20 Years On. Physiology (Bethesda) 2023; 38:0. [PMID: 36512352 PMCID: PMC10085559 DOI: 10.1152/physiol.00028.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/12/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022] Open
Abstract
The flagellar-specific Ca2+ channel CatSper is the predominant Ca2+ entry site in mammalian sperm. CatSper-mediated Ca2+ signaling affects nearly every event that regulates sperm to acquire fertilizing capability. In this review, we summarize some of the main findings from 20 years of CatSper research and highlight recent progress and prospects.
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Affiliation(s)
- Jae Yeon Hwang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Jean-Ju Chung
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
- Department of Gynecology and Obstetrics, Yale School of Medicine, New Haven, Connecticut
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7
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Liu J, Li X, Xu N, Han H, Li X. Role of ion channels in the mechanism of proteinuria (Review). Exp Ther Med 2022; 25:27. [PMID: 36561615 PMCID: PMC9748662 DOI: 10.3892/etm.2022.11726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/10/2022] [Indexed: 11/25/2022] Open
Abstract
Proteinuria is a common clinical manifestation of kidney diseases, such as glomerulonephritis, nephrotic syndrome, immunoglobulin A nephropathy and diabetic nephropathy. Therefore, proteinuria is considered to be a risk factor for renal dysfunction. Furthermore, proteinuria is also significantly associated with the progression of kidney diseases and increased mortality. Its occurrence is closely associated with damage to the structure of the glomerular filtration membrane. An impaired glomerular filtration membrane can affect the selective filtration function of the kidneys; therefore, several macromolecular substances, such as proteins, may pass through the filtration membrane and promote the manifestation of proteinuria. It has been reported that ion channels play a significant role in the mechanisms underlying proteinuria. Ion channel mutations or other dysfunctions have been implicated in several diseases, therefore ion channels could be used as major therapeutic targets. The mechanisms underlying the action of ion channels and ion transporters in proteinuria have been overlooked in the literature, despite their importance in identifying novel targets for treating proteinuria and delaying the progression of kidney diseases. The current review article focused on the four key ion channel groups, namely Na+, Ca2+, Cl- and K+ ion channels and the associated ion transporters.
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Affiliation(s)
- Jie Liu
- Department of Nephrology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261000, P.R. China
| | - Xuewei Li
- Department of Rheumatology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261000, P.R. China
| | - Ning Xu
- Department of Nephrology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261000, P.R. China
| | - Huirong Han
- Department of Anesthesiology, Weifang Medical University, Weifang, Shandong 261000, P.R. China
| | - Xiangling Li
- Department of Nephrology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261000, P.R. China,Correspondence to: Professor Xiangling Li, Department of Nephrology, Affiliated Hospital of Weifang Medical University, 2428 Yu He Road, Weifang, Shandong 261000, P.R. China
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8
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Abbott GW. Kv Channel Ancillary Subunits: Where Do We Go from Here? Physiology (Bethesda) 2022; 37:0. [PMID: 35797055 PMCID: PMC9394777 DOI: 10.1152/physiol.00005.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 01/10/2023] Open
Abstract
Voltage-gated potassium (Kv) channels each comprise four pore-forming α-subunits that orchestrate essential duties such as voltage sensing and K+ selectivity and conductance. In vivo, however, Kv channels also incorporate regulatory subunits-some Kv channel specific, others more general modifiers of protein folding, trafficking, and function. Understanding all the above is essential for a complete picture of the role of Kv channels in physiology and disease.
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Affiliation(s)
- Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
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9
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Recent Advances in Aptamer‐Based Nanopore Sensing at Single‐Molecule Resolution. Chem Asian J 2022; 17:e202200364. [DOI: 10.1002/asia.202200364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/20/2022] [Indexed: 11/07/2022]
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10
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Yang Z, Yang F, Liu JL, Wu HT, Yang H, Shi Y, Liu J, Zhang YF, Luo YR, Chen KM. Heavy metal transporters: Functional mechanisms, regulation, and application in phytoremediation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 809:151099. [PMID: 34688763 DOI: 10.1016/j.scitotenv.2021.151099] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 10/15/2021] [Accepted: 10/16/2021] [Indexed: 05/22/2023]
Abstract
Heavy metal pollution in soil is a global problem with serious impacts on human health and ecological security. Phytoextraction in phytoremediation, in which plants uptake and transport heavy metals (HMs) to the tissues of aerial parts, is the most environmentally friendly method to reduce the total amount of HMs in soil and has wide application prospects. However, the molecular mechanism of phytoextraction is still under investigation. The uptake, translocation, and retention of HMs in plants are mainly mediated by a variety of transporter proteins. A better understanding of the accumulation strategy of HMs via transporters in plants is a prerequisite for the improvement of phytoextraction. In this review, the biochemical structure and functions of HM transporter families in plants are systematically summarized, with emphasis on their roles in phytoremediation. The accumulation mechanism and regulatory pathways related to hormones, regulators, and reactive oxygen species (ROS) of HMs concerning these transporters are described in detail. Scientific efforts and practices for phytoremediation carried out in recent years suggest that creation of hyperaccumulators by transgenic or gene editing techniques targeted to these transporters and their regulators is the ultimate powerful path for the phytoremediation of HM contaminated soils.
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Affiliation(s)
- Zi Yang
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Fan Yang
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jia-Lan Liu
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Hai-Tao Wu
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Hao Yang
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yi Shi
- Guangdong Kaiyuan Environmental Technology Co., Ltd, Dongguan 523000, China
| | - Jie Liu
- Guangdong Kaiyuan Environmental Technology Co., Ltd, Dongguan 523000, China
| | - Yan-Feng Zhang
- Hybrid Rapeseed Research Center of Shaanxi Province, Yangling 712100, Shaanxi, China
| | - Yan-Rong Luo
- Guangdong Kaiyuan Environmental Technology Co., Ltd, Dongguan 523000, China.
| | - Kun-Ming Chen
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China.
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11
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Chen J, Zhang M, Ma Z, Yuan D, Zhu J, Tuo B, Li T, Liu X. Alteration and dysfunction of ion channels/transporters in a hypoxic microenvironment results in the development and progression of gastric cancer. Cell Oncol (Dordr) 2021; 44:739-749. [PMID: 33856653 PMCID: PMC8338819 DOI: 10.1007/s13402-021-00604-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2021] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Gastric cancer (GC) is one of the most common malignant cancers in the world and has only few treatment options and, concomitantly, a poor prognosis. It is generally accepted now that the tumor microenvironment, particularly that under hypoxia, plays an important role in cancer development. Hypoxia can regulate the energy metabolism and malignancy of tumor cells by inducing or altering various important factors, such as oxidative stress, reactive oxygen species (ROS), hypoxia-inducible factors (HIFs), autophagy and acidosis. In addition, altered expression and/or dysfunction of ion channels/transporters (ICTs) have been encountered in a variety of human tumors, including GC, and to play an important role in the processes of tumor cell proliferation, migration, invasion and apoptosis. Increasing evidence indicates that ICTs are at least partly involved in interactions between cancer cells and their hypoxic microenvironment. Here, we provide an overview of the different ICTs that regulate or are regulated by hypoxia in GC. CONCLUSIONS AND PERSPECTIVES Hypoxia is one of the major obstacles to cancer therapy. Regulating cellular responses and factors under hypoxia can inhibit GC. Similarly, altering the expression or activity of ICTs, such as the application of ion channel inhibitors, can slow down the growth and/or migration of GC cells. Since targeting the hypoxic microenvironment and/or ICTs may be a promising strategy for the treatment of GC, more attention should be paid to the interplay between ICTs and the development and progression of GC in such a microenvironment.
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Affiliation(s)
- Junling Chen
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
- Digestive Disease Institute of Guizhou Province, Zunyi, Guizhou Province, China
| | - Minglin Zhang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
- Digestive Disease Institute of Guizhou Province, Zunyi, Guizhou Province, China
| | - Zhiyuan Ma
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
- Digestive Disease Institute of Guizhou Province, Zunyi, Guizhou Province, China
- Department of Thyroid and Breast Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
| | - Dumin Yuan
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
- Digestive Disease Institute of Guizhou Province, Zunyi, Guizhou Province, China
| | - Jiaxing Zhu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
- Digestive Disease Institute of Guizhou Province, Zunyi, Guizhou Province, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
- Digestive Disease Institute of Guizhou Province, Zunyi, Guizhou Province, China
| | - Taolang Li
- Department of Thyroid and Breast Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China.
| | - Xuemei Liu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China.
- Digestive Disease Institute of Guizhou Province, Zunyi, Guizhou Province, China.
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12
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Control of Biophysical and Pharmacological Properties of Potassium Channels by Ancillary Subunits. Handb Exp Pharmacol 2021; 267:445-480. [PMID: 34247280 DOI: 10.1007/164_2021_512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Potassium channels facilitate and regulate physiological processes as diverse as electrical signaling, ion, solute and hormone secretion, fluid homeostasis, hearing, pain sensation, muscular contraction, and the heartbeat. Potassium channels are each formed by either a tetramer or dimer of pore-forming α subunits that co-assemble to create a multimer with a K+-selective pore that in most cases is capable of functioning as a discrete unit to pass K+ ions across the cell membrane. The reality in vivo, however, is that the potassium channel α subunit multimers co-assemble with ancillary subunits to serve specific physiological functions. The ancillary subunits impart specific physiological properties that are often required for a particular activity in vivo; in addition, ancillary subunit interaction often alters the pharmacology of the resultant complex. In this chapter the modes of action of ancillary subunits on K+ channel physiology and pharmacology are described and categorized into various mechanistic classes.
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13
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Yang J, Li W, Guo X, Chen P, Cheng Y, Mao K, Ma F. Cation/Ca 2+ Exchanger 1 (MdCCX1), a Plasma Membrane-Localized Na + Transporter, Enhances Plant Salt Tolerance by Inhibiting Excessive Accumulation of Na + and Reactive Oxygen Species. FRONTIERS IN PLANT SCIENCE 2021; 12:746189. [PMID: 34721472 PMCID: PMC8549818 DOI: 10.3389/fpls.2021.746189] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/20/2021] [Indexed: 05/18/2023]
Abstract
High salinity causes severe damage to plant growth and significantly reduces crop yields. The CCX family proteins can facilitate the transport of multiple ions to prevent toxicity. CCX proteins play an important role in regulating plant salt tolerance, but no detailed studies on CCX proteins in apples have been reported. Here, the CCX family gene MdCCX1 was cloned from apple (Malus domestica). It is constitutively expressed in various apple tissues and is significantly induced by salt stress. As a plasma membrane-localized protein, MdCCX1-overexpression could complement the Na+-sensitive phenotype of yeast mutants and reduce the Na+ content in yeast cells under NaCl treatment, suggesting that MdCCX1 could be a plasma membrane-localized Na+ transporter. To identify the function of MdCCX1 in salt response, we transformed this gene into Arabidopsis, apple calli, and apple plants. Overexpression of MdCCX1 significantly improved the salt tolerance of these transgenic materials. The significantly reduced Na+ content under NaCl treatment indicated that MdCCX1 overexpression could enhance plant salt tolerance by inhibiting the excessive accumulation of Na+. Besides, MdCCX1 overexpression could also enhance plant salt tolerance by promoting ROS scavenging. These findings provide new insight and rich resources for future studies of CCX proteins in plant species.
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14
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Li F, Egea PF, Vecchio AJ, Asial I, Gupta M, Paulino J, Bajaj R, Dickinson MS, Ferguson-Miller S, Monk BC, Stroud RM. Highlighting membrane protein structure and function: A celebration of the Protein Data Bank. J Biol Chem 2021; 296:100557. [PMID: 33744283 PMCID: PMC8102919 DOI: 10.1016/j.jbc.2021.100557] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/10/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
Biological membranes define the boundaries of cells and compartmentalize the chemical and physical processes required for life. Many biological processes are carried out by proteins embedded in or associated with such membranes. Determination of membrane protein (MP) structures at atomic or near-atomic resolution plays a vital role in elucidating their structural and functional impact in biology. This endeavor has determined 1198 unique MP structures as of early 2021. The value of these structures is expanded greatly by deposition of their three-dimensional (3D) coordinates into the Protein Data Bank (PDB) after the first atomic MP structure was elucidated in 1985. Since then, free access to MP structures facilitates broader and deeper understanding of MPs, which provides crucial new insights into their biological functions. Here we highlight the structural and functional biology of representative MPs and landmarks in the evolution of new technologies, with insights into key developments influenced by the PDB in magnifying their impact.
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Affiliation(s)
- Fei Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA; Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Pascal F Egea
- Department of Biological Chemistry, School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Alex J Vecchio
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | | | - Meghna Gupta
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Joana Paulino
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Ruchika Bajaj
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, USA
| | - Miles Sasha Dickinson
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Brian C Monk
- Sir John Walsh Research Institute and Department of Oral Sciences, University of Otago, North Dunedin, Dunedin, New Zealand
| | - Robert M Stroud
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA.
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15
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Ceder MM, Aggarwal T, Hosseini K, Maturi V, Patil S, Perland E, Williams MJ, Fredriksson R. CG4928 Is Vital for Renal Function in Fruit Flies and Membrane Potential in Cells: A First In-Depth Characterization of the Putative Solute Carrier UNC93A. Front Cell Dev Biol 2020; 8:580291. [PMID: 33163493 PMCID: PMC7591606 DOI: 10.3389/fcell.2020.580291] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 09/16/2020] [Indexed: 01/23/2023] Open
Abstract
The number of transporter proteins that are not fully characterized is immense. Here, we used Drosophila melanogaster and human cell lines to perform a first in-depth characterization of CG4928, an ortholog to the human UNC93A, of which little is known. Solute carriers regulate and maintain biochemical pathways important for the body, and malfunctioning transport is associated with multiple diseases. Based on phylogenetic analysis, CG4928 is closely related to human UNC93A and has a secondary and a tertiary protein structure and folding similar to major facilitator superfamily transporters. Ubiquitous knockdown of CG4928 causes flies to have a reduced secretion rate from the Malpighian tubules; altering potassium content in the body and in the Malpighian tubules, homologous to the renal system; and results in the development of edema. The edema could be rescued by using amiloride, a common diuretic, and by maintaining the flies on ion-free diets. CG4928-overexpressing cells did not facilitate the transport of sugars and amino acids; however, proximity ligation assay revealed that CG4928 co-localized with TASK1 channels. Overexpression of CG4928 resulted in induced apoptosis and cytotoxicity, which could be restored when cells were kept in high-sodium media. Furthermore, the basal membrane potential was observed to be disrupted. Taken together, the results indicate that CG4928 is of importance for generating the cellular membrane potential by an unknown manner. However, we speculate that it most likely acts as a regulator or transporter of potassium flows over the membrane.
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Affiliation(s)
- Mikaela M Ceder
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Tanya Aggarwal
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Kimia Hosseini
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Varun Maturi
- Department of Pharmacy, Drug Delivery, Uppsala University, Uppsala, Sweden
| | - Sourabh Patil
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Emelie Perland
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Michael J Williams
- Department of Neuroscience, Functional Pharmacology, Uppsala University, Uppsala, Sweden
| | - Robert Fredriksson
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
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16
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Bazard P, Ding B, Chittam HK, Zhu X, Parks TA, Taylor-Clark TE, Bhethanabotla VR, Frisina RD, Walton JP. Aldosterone up-regulates voltage-gated potassium currents and NKCC1 protein membrane fractions. Sci Rep 2020; 10:15604. [PMID: 32973172 PMCID: PMC7515911 DOI: 10.1038/s41598-020-72450-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 07/12/2020] [Indexed: 02/02/2023] Open
Abstract
Na+-K+-2Cl- Cotransporter (NKCC1) is a protein that aids in the active transport of sodium, potassium, and chloride ions across cell membranes. It has been shown that long-term systemic treatment with aldosterone (ALD) can enhance NKCC1 protein expression and activity in the aging cochlea resulting in improved hearing. In the present work, we used a cell line with confirmed NKCC1 expression to demonstrate that in vitro application of ALD increased outward voltage-gated potassium currents significantly, and simultaneously upregulated whole lysate and membrane portion NKCC1 protein expression. These ALD-induced changes were blocked by applying the mineralocorticoid receptor antagonist eplerenone. However, application of the NKCC1 inhibitor bumetanide or the potassium channel antagonist Tetraethyl ammonium had no effect. In addition, NKKC1 mRNA levels remained stable, indicating that ALD modulates NKCC1 protein expression via the activation of mineralocorticoid receptors and post-transcriptional modifications. Further, in vitro electrophysiology experiments, with ALD in the presence of NKCC1, K+ channel and mineralocorticoid receptor inhibitors, revealed interactions between NKCC1 and outward K+ channels, mediated by a mineralocorticoid receptor-ALD complex. These results provide evidence of the therapeutic potential of ALD for the prevention/treatment of inner ear disorders such as age-related hearing loss.
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Affiliation(s)
- Parveen Bazard
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL, 33612, USA
| | - Bo Ding
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL, 33612, USA
| | - Harish K Chittam
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL, 33612, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL, 33612, USA
| | - Thomas A Parks
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33620, USA
| | - Thomas E Taylor-Clark
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33620, USA
| | - Venkat R Bhethanabotla
- Department of Chemical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL, 33612, USA
| | - Robert D Frisina
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA
- Department Communication Sciences and Disorders, College of Behavioral and Communication Sciences, Tampa, FL, 33620, USA
- Department of Chemical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL, 33612, USA
| | - Joseph P Walton
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA.
- Department Communication Sciences and Disorders, College of Behavioral and Communication Sciences, Tampa, FL, 33620, USA.
- Department of Chemical Engineering, College of Engineering, University of South Florida, Tampa, FL, 33620, USA.
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL, 33612, USA.
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17
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Suresh J, Khor IW, Kaur P, Heng HL, Torta F, Dawe GS, Tai ES, Tolwinski NS. Shared signaling pathways in Alzheimer’s and metabolic disease may point to new treatment approaches. FEBS J 2020; 288:3855-3873. [DOI: 10.1111/febs.15540] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/18/2020] [Accepted: 08/21/2020] [Indexed: 12/18/2022]
Affiliation(s)
| | - Ing Wei Khor
- Department of Medicine Yong Loo Lin School of MedicineNational University of Singapore
| | - Prameet Kaur
- Science Division Yale‐ NUS College Singapore Singapore
| | - Hui Li Heng
- Department of Pharmacology Yong Loo Lin School of Medicine National University of Singapore, and Neurobiology Programme
- Life Sciences Institute National University of Singapore Singapore
| | - Federico Torta
- Singapore Lipidomics Incubator Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore Singapore
| | - Gavin S. Dawe
- Department of Pharmacology Yong Loo Lin School of Medicine National University of Singapore, and Neurobiology Programme
- Life Sciences Institute National University of Singapore Singapore
| | - E Shyong Tai
- Department of Medicine Yong Loo Lin School of MedicineNational University of Singapore
- Division of Endocrinology National University HospitalNational University Health System
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18
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Barrese V, Stott JB, Baldwin SN, Mondejar-Parreño G, Greenwood IA. SMIT (Sodium-Myo-Inositol Transporter) 1 Regulates Arterial Contractility Through the Modulation of Vascular Kv7 Channels. Arterioscler Thromb Vasc Biol 2020; 40:2468-2480. [PMID: 32787517 PMCID: PMC7505149 DOI: 10.1161/atvbaha.120.315096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Supplemental Digital Content is available in the text. Objective: The SMIT1 (sodium:myo-inositol transporter 1) regulates myo-inositol movement into cells and responses to hypertonic stimuli. Alteration of myo-inositol levels has been associated with several diseases, including hypertension, but there is no evidence of a functional role of SMIT1 in the vasculature. Recent evidence showed that in the nervous system SMIT1 interacted and modulated the function of members of the Kv7 family of voltage-gated potassium channels, which are also expressed in the vasculature where they regulate arterial contractility. Therefore, in this study, we evaluated whether SMIT1 was functionally relevant in arterial smooth muscle. Approach and Results: Immunofluorescence and polymerase chain reaction experiments revealed that SMIT1 was expressed in rat renal and mesenteric vascular smooth muscle cells. Isometric tension recordings showed that incubation of renal arteries with raffinose and myo-inositol (which increases SMIT1 expression) reduced the contractile responses to methoxamine, an effect that was abolished by preincubation with the pan-Kv7 blocker linopirdine and by molecular knockdown of Kv7.4 and Kv7.5. Knockdown of SMIT1 increased the contraction of renal arteries induced by methoxamine, impaired the response to the Kv7.2–Kv7.5 activator ML213 but did not interfere with the relaxant responses induced by openers of other potassium channels. Proximity ligation assay showed that SMIT1 interacted with heteromeric channels formed by Kv7.4 and Kv7.5 proteins in both renal and mesenteric vascular smooth muscle cells. Patch-clamp experiments showed that incubation with raffinose plus myo-inositol increased Kv7 currents in vascular smooth muscle cells. Conclusions: SMIT1 protein is expressed in vascular smooth muscle cells where it modulates arterial contractility through an association with Kv7.4/Kv7.5 heteromers.
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Affiliation(s)
- Vincenzo Barrese
- Vascular Research Centre, Institute of Molecular & Clinical Sciences, St George's, University of London, United Kingdom (V.B., J.B.S., S.N.B., I.A.G.).,Department of Neuroscience, Reproductive Science and Dentistry, University of Naples Federico II, Italy (V.B.)
| | - Jennifer B Stott
- Vascular Research Centre, Institute of Molecular & Clinical Sciences, St George's, University of London, United Kingdom (V.B., J.B.S., S.N.B., I.A.G.)
| | - Samuel N Baldwin
- Vascular Research Centre, Institute of Molecular & Clinical Sciences, St George's, University of London, United Kingdom (V.B., J.B.S., S.N.B., I.A.G.)
| | - Gema Mondejar-Parreño
- Department of Pharmacology and Toxicology. School of Medicine, Universidad Complutense de Madrid, Spain (G.M.-P.)
| | - Iain A Greenwood
- Vascular Research Centre, Institute of Molecular & Clinical Sciences, St George's, University of London, United Kingdom (V.B., J.B.S., S.N.B., I.A.G.)
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19
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Compound Chai Jin Jie Yu Tablets, Acts as An Antidepressant by Promoting Synaptic Function in the Hippocampal Neurons. DIGITAL CHINESE MEDICINE 2020. [DOI: 10.1016/j.dcmed.2020.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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20
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Genetic analysis of SLC26A4 gene (pendrin) related deafness among a cohort of assortative mating families from southern India. Eur Arch Otorhinolaryngol 2020; 277:3021-3035. [DOI: 10.1007/s00405-020-06026-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 04/27/2020] [Indexed: 10/24/2022]
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21
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Farshad M, Rasaiah JC. Reverse Translocation of Nucleotides through a Carbon Nanotube. J Phys Chem B 2020; 124:937-943. [PMID: 31917564 DOI: 10.1021/acs.jpcb.9b09587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report molecular dynamics (MD) simulations of the reverse translocation of single nucleotides through a narrow carbon nanotube (CNT), with a diameter of 1.36 nm, immersed in a 1 M KCl electrolyte solution under an applied electric field along the tube axis. We observe ion selectivity by the narrow CNT, which leads to a high flow of K+ ions, in contrast to a negligible and opposing current of Cl- ions. The K+ ions, driven by the electric field, force a negatively charged single nucleotide into the narrow CNT where it is trapped by the incoming K+ ions and water molecules, and the nucleotide is driven in the same direction as the K+ ions. This illustrates a novel mechanism of nucleotide reverse translocation that is controlled by ion selectivity. An increase in the CNT diameter to 2.71 nm or an increase in nucleotide chain length both lead to translocation in the normal direction of the applied field. The reverse translocation rate of single nucleotides is correlated to the ionic current of K+ ions in the narrow tube, unlike translocation in the normal direction in the wider tube.
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Affiliation(s)
- Mohsen Farshad
- Department of Chemistry , University of Maine , Orono , Maine 04469 , United States
| | - Jayendran C Rasaiah
- Department of Chemistry , University of Maine , Orono , Maine 04469 , United States
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22
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Müller WE, Schröder HC, Wang X. Inorganic Polyphosphates As Storage for and Generator of Metabolic Energy in the Extracellular Matrix. Chem Rev 2019; 119:12337-12374. [PMID: 31738523 PMCID: PMC6935868 DOI: 10.1021/acs.chemrev.9b00460] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Indexed: 12/14/2022]
Abstract
Inorganic polyphosphates (polyP) consist of linear chains of orthophosphate residues, linked by high-energy phosphoanhydride bonds. They are evolutionarily old biopolymers that are present from bacteria to man. No other molecule concentrates as much (bio)chemically usable energy as polyP. However, the function and metabolism of this long-neglected polymer are scarcely known, especially in higher eukaryotes. In recent years, interest in polyP experienced a renaissance, beginning with the discovery of polyP as phosphate source in bone mineralization. Later, two discoveries placed polyP into the focus of regenerative medicine applications. First, polyP shows morphogenetic activity, i.e., induces cell differentiation via gene induction, and, second, acts as an energy storage and donor in the extracellular space. Studies on acidocalcisomes and mitochondria provided first insights into the enzymatic basis of eukaryotic polyP formation. In addition, a concerted action of alkaline phosphatase and adenylate kinase proved crucial for ADP/ATP generation from polyP. PolyP added extracellularly to mammalian cells resulted in a 3-fold increase of ATP. The importance and mechanism of this phosphotransfer reaction for energy-consuming processes in the extracellular matrix are discussed. This review aims to give a critical overview about the formation and function of this unique polymer that is capable of storing (bio)chemically useful energy.
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Affiliation(s)
- Werner E.G. Müller
- ERC Advanced Investigator
Grant Research
Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany
| | - Heinz C. Schröder
- ERC Advanced Investigator
Grant Research
Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany
| | - Xiaohong Wang
- ERC Advanced Investigator
Grant Research
Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany
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23
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Niño-González M, Novo-Uzal E, Richardson DN, Barros PM, Duque P. More Transporters, More Substrates: The Arabidopsis Major Facilitator Superfamily Revisited. MOLECULAR PLANT 2019; 12:1182-1202. [PMID: 31330327 DOI: 10.1016/j.molp.2019.07.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 05/20/2023]
Abstract
The Major Facilitator Superfamily (MFS) is ubiquitous in living organisms and represents the largest group of secondary active membrane transporters. In plants, significant research efforts have focused on the role of specific families within the MFS, particularly those transporting macronutrients (C, N, and P) that constitute the vast majority of the members of this superfamily. Other MFS families remain less explored, although a plethora of additional substrates and physiological functions have been uncovered. Nevertheless, the lack of a systematic approach to analyzing the MFS as a whole has obscured the high diversity and versatility of these transporters. Here, we present a phylogenetic analysis of all annotated MFS domain-containing proteins encoded in the Arabidopsis thaliana genome and propose that this superfamily of transporters consists of 218 members, clustered in 22 families. In reviewing the available information regarding the diversity in biological functions and substrates of Arabidopsis MFS members, we provide arguments for intensified research on these membrane transporters to unveil the breadth of their physiological relevance, disclose the molecular mechanisms underlying their mode of action, and explore their biotechnological potential.
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Affiliation(s)
| | | | | | - Pedro M Barros
- Genomics of Plant Stress Unit, ITQB NOVA - Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | - Paula Duque
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal.
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24
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Ion Transporters, Channelopathies, and Glucose Disorders. Int J Mol Sci 2019; 20:ijms20102590. [PMID: 31137773 PMCID: PMC6566632 DOI: 10.3390/ijms20102590] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 01/19/2023] Open
Abstract
Ion channels and transporters play essential roles in excitable cells including cardiac, skeletal and smooth muscle cells, neurons, and endocrine cells. In pancreatic beta-cells, for example, potassium KATP channels link the metabolic signals generated inside the cell to changes in the beta-cell membrane potential, and ultimately regulate insulin secretion. Mutations in the genes encoding some ion transporter and channel proteins lead to disorders of glucose homeostasis (hyperinsulinaemic hypoglycaemia and different forms of diabetes mellitus). Pancreatic KATP, Non-KATP, and some calcium channelopathies and MCT1 transporter defects can lead to various forms of hyperinsulinaemic hypoglycaemia (HH). Mutations in the genes encoding the pancreatic KATP channels can also lead to different types of diabetes (including neonatal diabetes mellitus (NDM) and Maturity Onset Diabetes of the Young, MODY), and defects in the solute carrier family 2 member 2 (SLC2A2) leads to diabetes mellitus as part of the Fanconi–Bickel syndrome. Variants or polymorphisms in some ion channel genes and transporters have been reported in association with type 2 diabetes mellitus.
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25
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Nastou KC, Batskinis MA, Litou ZI, Hamodrakas SJ, Iconomidou VA. Analysis of Single-Nucleotide Polymorphisms in Human Voltage-Gated Ion Channels. J Proteome Res 2019; 18:2310-2320. [DOI: 10.1021/acs.jproteome.9b00121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Katerina C. Nastou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Michail A. Batskinis
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Zoi I. Litou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Stavros J. Hamodrakas
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Vassiliki A. Iconomidou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
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26
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Quantitative Model for Ion Transport and Cytoplasm Conductivity of Chinese Hamster Ovary Cells. Sci Rep 2018; 8:17818. [PMID: 30546044 PMCID: PMC6292909 DOI: 10.1038/s41598-018-36127-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/09/2018] [Indexed: 01/29/2023] Open
Abstract
In mammalian cells cytoplasm ion concentrations and hence cytoplasm conductivity is an important indicator of their physiological state. Changes in the cytoplasm conductivity has been associated with physiological changes such as progression of cancer and apoptosis. In this work, a model that predicts the effects of physiological changes in ion transport on the cytoplasm conductivity of Chinese hamster ovary (CHO) cells is demonstrated. We determined CHO-specific model parameters, Na+/K+ ATPase pumps and ion channels densities, using a flux assay approach. The obtained sodium (PNa), potassium (PK) and chloride (PCl) permeability and Na+/K+ ATPase pump density were estimated to be 5.6 × 10-8 cm/s, 5.6 × 10-8 cm/s, 3.2 × 10-7 cm/s and 2.56 × 10-11 mol/cm2, respectively. The model was tested by comparing the model predictions with the experimentally determined temporal changes in the cytoplasm conductivity of Na+/K+ ATPase pump inhibited CHO cells. Cells' Na+/K+ ATPase pumps were inhibited using 5 mM Ouabain and the temporal behavior of their cytoplasm conductivity was measured using dielectrophoresis cytometry. The measured results are in close agreement with the model-calculated values. This model will provide insight on the effects of processes such as apoptosis or external media ion concentration on the cytoplasm conductivity of mammalian cells.
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27
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Baronas VA, Yang RY, Morales LC, Sipione S, Kurata HT. Slc7a5 regulates Kv1.2 channels and modifies functional outcomes of epilepsy-linked channel mutations. Nat Commun 2018; 9:4417. [PMID: 30356053 PMCID: PMC6200743 DOI: 10.1038/s41467-018-06859-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 10/02/2018] [Indexed: 01/25/2023] Open
Abstract
Kv1.2 is a prominent voltage-gated potassium channel that influences action potential generation and propagation in the central nervous system. We explored multi-protein complexes containing Kv1.2 using mass spectrometry followed by screening for effects on Kv1.2. We report that Slc7a5, a neutral amino acid transporter, has a profound impact on Kv1.2. Co-expression with Slc7a5 reduces total Kv1.2 protein, and dramatically hyperpolarizes the voltage-dependence of activation by -47 mV. These effects are attenuated by expression of Slc3a2, a known binding partner of Slc7a5. The profound Slc7a5-mediated current suppression is partly explained by a combination of gating effects including accelerated inactivation and a hyperpolarizing shift of channel activation, causing channels to accumulate in a non-conducting state. Two recently reported Slc7a5 mutations linked to neurodevelopmental delay exhibit a localization defect and have attenuated effects on Kv1.2. In addition, epilepsy-linked gain-of-function Kv1.2 mutants exhibit enhanced sensitivity to Slc7a5.
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Affiliation(s)
- Victoria A Baronas
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Runying Y Yang
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Luis Carlos Morales
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Simonetta Sipione
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Harley T Kurata
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada. .,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada. .,Alberta Diabetes Institute, University of Alberta, Edmonton, Canada.
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28
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SMIT1 Modifies KCNQ Channel Function and Pharmacology by Physical Interaction with the Pore. Biophys J 2017; 113:613-626. [PMID: 28793216 DOI: 10.1016/j.bpj.2017.06.055] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/26/2017] [Accepted: 06/12/2017] [Indexed: 11/22/2022] Open
Abstract
Voltage-gated potassium channels of the KCNQ (Kv7) subfamily are essential for control of cellular excitability and repolarization in a wide range of cell types. Recently, we and others found that some KCNQ channels functionally and physically interact with sodium-dependent solute transporters, including myo-inositol transporters SMIT1 and SMIT2, potentially facilitating various modes of channel-transporter signal integration. In contrast to indirect effects such as channel regulation by SMIT-transported, myo-inositol-derived phosphatidylinositol 4,5-bisphosphate (PIP2), the mechanisms and functional consequences of the physical interaction of channels with transporters have been little studied. Here, using co-immunoprecipitation with different channel domains, we found that SMIT1 binds to the KCNQ2 pore module. We next tested the effects of SMIT1 co-expression, in the absence of extracellular myo-inositol or other SMIT1 substrates, on fundamental functional attributes of KCNQ2, KCNQ2/3, KCNQ1, and KCNQ1-KCNE1 channels. Without exception, SMIT1 altered KCNQ ion selectivity, sensitivity to extracellular K+, and pharmacology, consistent with an impact on conformation of the KCNQ pore. SMIT1 also altered the gating kinetics and/or voltage dependence of KCNQ2, KCNQ2/3, and KCNQ1-KCNE1. In contrast, SMIT1 had no effect on Kv1.1 (KCNA1) gating, ion selectivity, or pharmacology. We conclude that, independent of its transport activity and indirect regulatory mechanisms involving inositol-derived increases in PIP2, SMIT1, and likely other related sodium-dependent solute transporters, regulates KCNQ channel ion selectivity, gating, and pharmacology by direct physical interaction with the pore module.
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Kim EZ, Vienne J, Rosbash M, Griffith LC. Nonreciprocal homeostatic compensation in Drosophila potassium channel mutants. J Neurophysiol 2017; 117:2125-2136. [PMID: 28298298 DOI: 10.1152/jn.00002.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/06/2017] [Accepted: 03/11/2017] [Indexed: 01/30/2023] Open
Abstract
Homeostatic control of intrinsic excitability is important for long-term regulation of neuronal activity. In conjunction with many other forms of plasticity, intrinsic homeostasis helps neurons maintain stable activity regimes in the face of external input variability and destabilizing genetic mutations. In this study, we report a mechanism by which Drosophila melanogaster larval motor neurons stabilize hyperactivity induced by the loss of the delayed rectifying K+ channel Shaker cognate B (Shab), by upregulating the Ca2+-dependent K+ channel encoded by the slowpoke (slo) gene. We also show that loss of SLO does not trigger a reciprocal compensatory upregulation of SHAB, implying that homeostatic signaling pathways utilize compensatory pathways unique to the channel that was mutated. SLO upregulation due to loss of SHAB involves nuclear Ca2+ signaling and dCREB, suggesting that the slo homeostatic response is transcriptionally mediated. Examination of the changes in gene expression induced by these mutations suggests that there is not a generic transcriptional response to increased excitability in motor neurons, but that homeostatic compensations are influenced by the identity of the lost conductance.NEW & NOTEWORTHY The idea that activity-dependent homeostatic plasticity is driven solely by firing has wide credence. In this report we show that homeostatic compensation after loss of an ion channel conductance is tailored to identity of the channel lost, not its properties.
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Affiliation(s)
- Eugene Z Kim
- Department of Biology, Volen Center for Complex Systems, and National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts; and
| | - Julie Vienne
- Department of Biology, Volen Center for Complex Systems, and National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts; and
| | - Michael Rosbash
- Department of Biology, Volen Center for Complex Systems, and National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts; and.,Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts
| | - Leslie C Griffith
- Department of Biology, Volen Center for Complex Systems, and National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts; and
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