1
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Zhang C, Wang X, Fang D, Xu P, Mo X, Hu C, Abdelatty A, Wang M, Xu H, Sun Q, Zhou G, She J, Xia J, Hui KM, Xia H. STK39 is a novel kinase contributing to the progression of hepatocellular carcinoma by the PLK1/ERK signaling pathway. Theranostics 2021; 11:2108-2122. [PMID: 33500714 PMCID: PMC7797677 DOI: 10.7150/thno.48112] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023] Open
Abstract
Rationale: Protein kinases are critical therapeutic targets for curing hepatocellular carcinoma (HCC). As a serine/threonine kinase, the potential roles of serine/threonine kinase 39 (STK39) in HCC remain to be explored. Methods: The expression of STK39 was examined by RT-qPCR, western blotting and immunohistochemistry. Cell proliferation and apoptosis were detected by CCK8 and TUNEL kit. Cell migration and invasion assays were performed using a transwell system with or without Matrigel. RNA-seq, mass spectrometry and luciferase reporter assays were used to identify STK39 binding proteins. Results: Here, we firstly report that STK39 was highly overexpressed in clinical HCC tissues compared with adjacent tissues, high expression of STK39 was induced by transcription factor SP1 and correlated with poor patient survival. Gain and loss of function assays revealed that overexpression of STK39 promoted HCC cell proliferation, migration and invasion. In contrast, the depletion of STK39 attenuated the growth and metastasis of HCC cells. Moreover, knockdown of STK39 induced the HCC cell cycle arrested in the G2/M phase and promoted apoptosis. In mechanistic studies, RNA-seq revealed that STK39 positively regulated the ERK signaling pathway. Mass spectrometry identified that STK39 bound to PLK1 and STK39 promoted HCC progression and activated ERK signaling pathway dependent on PLK1. Conclusions: Thus, our study uncovers a novel role of STK39/PLK1/ERK signaling axis in the progress of HCC and suggests STK39 as an indicator for prognosis and a potential drug target of HCC.
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Affiliation(s)
- Chengfei Zhang
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
- Jiangsu Cancer Hospital, The Affiliated Cancer Hospital of Nanjing Medical University, Jiangsu Institute of Cancer Research, Nanjing 210009, Jiangsu, China
| | - Xiaoming Wang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Wannan Medical College, Wuhu 241001, Anhui, China
| | - Dan Fang
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Ping Xu
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Xiao Mo
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Chao Hu
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Alaa Abdelatty
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Mei Wang
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Haojun Xu
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Qi Sun
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Guoren Zhou
- Jiangsu Cancer Hospital, The Affiliated Cancer Hospital of Nanjing Medical University, Jiangsu Institute of Cancer Research, Nanjing 210009, Jiangsu, China
| | - Junjun She
- Department of High Talent & General Surgery & Med-X Institute, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, 710061, Shaanxi, China
| | - Jinglin Xia
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang, China
| | - Kam Man Hui
- Laboratory of Cancer Genomics, National Cancer Centre Singapore & Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore
| | - Hongping Xia
- Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China
- Jiangsu Cancer Hospital, The Affiliated Cancer Hospital of Nanjing Medical University, Jiangsu Institute of Cancer Research, Nanjing 210009, Jiangsu, China
- Department of High Talent & General Surgery & Med-X Institute, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, 710061, Shaanxi, China
- Laboratory of Cancer Genomics, National Cancer Centre Singapore & Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore
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2
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Catalán MA, Julio-Kalajzić F, Niemeyer MI, Cid LP, Sepúlveda FV. Short Chain Fatty Acids Effect on Chloride Channel ClC-2 as a Possible Mechanism for Lubiprostone Intestinal Action. Cells 2020; 9:cells9081781. [PMID: 32722648 PMCID: PMC7464869 DOI: 10.3390/cells9081781] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 01/22/2023] Open
Abstract
Lubiprostone, a 20-carbon synthetic fatty acid used for the treatment of constipation, is thought to act through an action on Cl− channel ClC-2. Short chain fatty acids (SCFAs) are produced and absorbed in the distal intestine. We explore whether SCFAs affect ClC-2, re-examine a possible direct effect of lubiprostone on ClC-2, and use mice deficient in ClC-2 to stringently address the hypothesis that the epithelial effect of lubiprostone targets this anion channel. Patch-clamp whole cell recordings of ClC-2 expressed in mammalian cells are used to assay SCFA and lubiprostone effects. Using chamber measurements of ion current in mice deficient in ClC-2 or CFTR channels served to analyze the target of lubiprostone in the distal intestinal epithelium. Intracellular SCFAs had a dual action on ClC-2, partially inhibiting conduction but, importantly, facilitating the voltage activation of ClC-2. Intra- or extracellular lubiprostone had no effect on ClC-2 currents. Lubiprostone elicited a secretory current across colonic epithelia that was increased in mice deficient in ClC-2, consistent with the channel’s proposed proabsorptive function, but absent from those deficient in CFTR. Whilst SCFAs might exert a physiological effect on ClC-2 as part of their known proabsorptive effect, ClC-2 plays no part in the lubiprostone intestinal effect that appears mediated by CFTR activation.
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Affiliation(s)
- Marcelo A. Catalán
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile
- Correspondence: (M.A.C.); (F.V.S.); Tel.: +56-63-2221686 (M.A.C.)
| | - Francisca Julio-Kalajzić
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - María Isabel Niemeyer
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - Luis Pablo Cid
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - Francisco V. Sepúlveda
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
- Correspondence: (M.A.C.); (F.V.S.); Tel.: +56-63-2221686 (M.A.C.)
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3
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Bi Y, Li C, Zhang Y, Wang Y, Chen S, Yue Q, Hoover RS, Wang XH, Delpire E, Eaton DC, Zhuang J, Cai H. Stimulatory Role of SPAK Signaling in the Regulation of Large Conductance Ca 2+-Activated Potassium (BK) Channel Protein Expression in Kidney. Front Physiol 2020; 11:638. [PMID: 32714200 PMCID: PMC7343913 DOI: 10.3389/fphys.2020.00638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 05/20/2020] [Indexed: 12/30/2022] Open
Abstract
SPS1-related proline/alanine-rich kinase (SPAK) plays important roles in regulating the function of numerous ion channels and transporters. With-no-lysine (WNK) kinase phosphorylates SPAK kinase to active the SPAK signaling pathway. Our previous studies indicated that WNK kinases regulate the activity of the large-conductance Ca2+-activated K+ (BK) channel and its protein expression via the ERK1/2 signaling pathway. It remains largely unknown whether SPAK kinase directly modulates the BK protein expression in kidney. In this study, we investigated the effect of SPAK on renal BK protein expression in both HEK293 cells and mouse kidney. In HEK293 cells, siRNA-mediated knockdown of SPAK expression significantly reduced BK protein expression and increased ERK1/2 phosphorylation, whereas overexpression of SPAK significantly enhanced BK expression and decreased ERK1/2 phosphorylation in a dose-dependent manner. Knockdown of ERK1/2 prevented SPAK siRNA-mediated inhibition of BK expression. Similarly, pretreatment of HEK293 cells with either the lysosomal inhibitor bafilomycin A1 or the proteasomal inhibitor MG132 reversed the inhibitory effects of SPAK knockdown on BK expression. We also found that there is no BK channel activity in PCs of CCD in SPAK KO mice using the isolated split-open tubule single-cell patching. In addition, we found that BK protein abundance in the kidney of SPAK knockout mice was significantly decreased and ERK1/2 phosphorylation was significantly enhanced. A high-potassium diet significantly increased BK protein abundance and SPAK phosphorylation levels, while reducing ERK1/2 phosphorylation levels. These findings suggest that SPAK enhances BK protein expression by reducing ERK1/2 signaling-mediated lysosomal and proteasomal degradations of the BK channel.
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Affiliation(s)
- Ye Bi
- Department of Pediatric Nephrology, The Second Affiliated Hospital/Yuying Children Hospital, Wenzhou Medical University, Wenzhou, China.,Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States
| | - Chunmei Li
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States
| | - Yiqian Zhang
- Department of Pediatric Nephrology, The Second Affiliated Hospital/Yuying Children Hospital, Wenzhou Medical University, Wenzhou, China
| | - Yunman Wang
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States
| | - Shan Chen
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States
| | - Qiang Yue
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, United States
| | - Robert S Hoover
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States.,Section of Nephrology, Atlanta Veterans Administration Medical Center, Decatur, GA, United States
| | - Xiaonan H Wang
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University Medical School, Nashville, TN, United States
| | - Douglas C Eaton
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States.,Department of Physiology, Emory University School of Medicine, Atlanta, GA, United States
| | - Jieqiu Zhuang
- Department of Pediatric Nephrology, The Second Affiliated Hospital/Yuying Children Hospital, Wenzhou Medical University, Wenzhou, China
| | - Hui Cai
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States.,Section of Nephrology, Atlanta Veterans Administration Medical Center, Decatur, GA, United States
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4
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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5
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Wang H, Xu M, Kong Q, Sun P, Yan F, Tian W, Wang X. Research and progress on ClC‑2 (Review). Mol Med Rep 2017; 16:11-22. [PMID: 28534947 PMCID: PMC5482133 DOI: 10.3892/mmr.2017.6600] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 02/13/2017] [Indexed: 12/22/2022] Open
Abstract
Chloride channel 2 (ClC-2) is one of the nine mammalian members of the ClC family. The present review discusses the molecular properties of ClC‑2, including CLCN2, ClC‑2 promoter and the structural properties of ClC‑2 protein; physiological properties; functional properties, including the regulation of cell volume. The effects of ClC‑2 on the digestive, respiratory, circulatory, nervous and optical systems are also discussed, in addition to the mechanisms involved in the regulation of ClC‑2. The review then discusses the diseases associated with ClC‑2, including degeneration of the retina, Sjögren's syndrome, age‑related cataracts, degeneration of the testes, azoospermia, lung cancer, constipation, repair of impaired intestinal mucosa barrier, leukemia, cystic fibrosis, leukoencephalopathy, epilepsy and diabetes mellitus. It was concluded that future investigations of ClC‑2 are likely to be focused on developing specific drugs, activators and inhibitors regulating the expression of ClC‑2 to treat diseases associated with ClC‑2. The determination of CLCN2 is required to prevent and treat several diseases associated with ClC‑2.
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Affiliation(s)
- Hongwei Wang
- Department of Ophthalmology, People's Hospital of Jingjiang, Jingjiang, Jiangsu 214500, P.R. China
| | - Minghui Xu
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
| | - Qingjie Kong
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, Jilin 130024, P.R. China
| | - Peng Sun
- Department of Ophthalmology, The First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang 154000, P.R. China
| | - Fengyun Yan
- Assets Division, Harbin University of Science and Technology, Harbin, Heilongjiang 150080, P.R. China
| | - Wenying Tian
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
| | - Xin Wang
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
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6
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Abstract
WNK (With-No-Lysine (K)) kinases are serine-threonine kinases characterized by an atypical placement of a catalytic lysine within the kinase domain. Mutations in human WNK1 or WNK4 cause an autosomal dominant syndrome of hypertension and hyperkalemia, reflecting the fact that WNK kinases are critical regulators of renal ion transport processes. Here, the role of WNKs in the regulation of ion transport processes in vertebrate and invertebrate renal function, cellular and organismal osmoregulation, and cell migration and cerebral edema will be reviewed, along with emerging literature demonstrating roles for WNKs in cardiovascular and neural development, Wnt signaling, and cancer. Conserved roles for these kinases across phyla are emphasized.
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Affiliation(s)
| | - Andreas Jenny
- Albert Einstein College of Medicine, New York, NY, United States.
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7
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Abousaab A, Warsi J, Elvira B, Lang F. Caveolin-1 Sensitivity of Excitatory Amino Acid Transporters EAAT1, EAAT2, EAAT3, and EAAT4. J Membr Biol 2015; 249:239-49. [PMID: 26690923 DOI: 10.1007/s00232-015-9863-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 12/07/2015] [Indexed: 10/22/2022]
Abstract
Excitatory amino acid transporters EAAT1 (SLC1A3), EAAT2 (SLC1A2), EAAT3 (SLC1A1), and EAAT4 (SLC1A6) serve to clear L-glutamate from the synaptic cleft and are thus important for the limitation of neuronal excitation. EAAT3 has previously been shown to form complexes with caveolin-1, a major component of caveolae, which participate in the regulation of transport proteins. The present study explored the impact of caveolin-1 on electrogenic transport by excitatory amino acid transporter isoforms EAAT1-4. To this end cRNA encoding EAAT1, EAAT2, EAAT3, or EAAT4 was injected into Xenopus oocytes without or with additional injection of cRNA encoding caveolin-1. The L-glutamate (2 mM)-induced inward current (I Glu) was taken as a measure of glutamate transport. As a result, I Glu was observed in EAAT1-, EAAT2-, EAAT3-, or EAAT4-expressing oocytes but not in water-injected oocytes, and was significantly decreased by coexpression of caveolin-1. Caveolin-1 decreased significantly the maximal transport rate. Treatment of EAATs-expressing oocytes with brefeldin A (5 µM) was followed by a decrease in conductance, which was similar in oocytes expressing EAAT together with caveolin-1 as in oocytes expressing EAAT1-4 alone. Thus, caveolin-1 apparently does not accelerate transporter protein retrieval from the cell membrane. In conclusion, caveolin-1 is a powerful negative regulator of the excitatory glutamate transporters EAAT1, EAAT2, EAAT3, and EAAT4.
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Affiliation(s)
- Abeer Abousaab
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Jamshed Warsi
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Bernat Elvira
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Florian Lang
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany.
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8
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Fezai M, Elvira B, Warsi J, Ben-Attia M, Hosseinzadeh Z, Lang F. Up-Regulation of Intestinal Phosphate Transporter NaPi-IIb (SLC34A2) by the Kinases SPAK and OSR1. Kidney Blood Press Res 2015; 40:555-64. [PMID: 26506223 DOI: 10.1159/000368531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1), kinases controlled by WNK (with-no-K[Lys] kinase), are powerful regulators of cellular ion transport and blood pressure. Observations in gene-targeted mice disclosed an impact of SPAK/OSR1 on phosphate metabolism. The present study thus tested whether SPAK and/or OSR1 contributes to the regulation of the intestinal Na(+)-coupled phosphate co-transporter NaPi-IIb (SLC34A2). METHODS cRNA encoding NaPi-IIb was injected into Xenopus laevis oocytes without or with additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 or catalytically inactive (D164A)OSR1. The phosphate (1 mM)-induced inward current (I(Pi)) was taken as measure of phosphate transport. RESULTS I(Pi) was observed in NaPi-IIb expressing oocytes but not in water injected oocytes, and was significantly increased by co-expression of SPAK, (T233E)SPAK, OSR1, (T185E)OSR1 or SPAK+OSR1, but not by co-expression of (T233A)SPAK, (D212A)SPAK, (T185A)OSR1, or (D164A)OSR1. SPAK and OSR1 both increased the maximal transport rate of the carrier. CONCLUSIONS SPAK and OSR1 are powerful stimulators of the intestinal Na+-coupled phosphate co-transporter NaPi-IIb.
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Affiliation(s)
- Myriam Fezai
- Department of Physiology I, University of Tx00FC;bingen, Tx00FC;bingen, Germany
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9
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Abousaab A, Warsi J, Elvira B, Alesutan I, Hoseinzadeh Z, Lang F. Down-Regulation of Excitatory Amino Acid Transporters EAAT1 and EAAT2 by the Kinases SPAK and OSR1. J Membr Biol 2015; 248:1107-19. [PMID: 26233565 DOI: 10.1007/s00232-015-9826-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/24/2015] [Indexed: 11/27/2022]
Abstract
SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1) are cell volume-sensitive kinases regulated by WNK (with-no-K[Lys]) kinases. SPAK/OSR1 regulate several channels and carriers. SPAK/OSR1 sensitive functions include neuronal excitability. Orchestration of neuronal excitation involves the excitatory glutamate transporters EAAT1 and EAAT2. Sensitivity of those carriers to SPAK/OSR1 has never been shown. The present study thus explored whether SPAK and/or OSR1 contribute to the regulation of EAAT1 and/or EAAT2. To this end, cRNA encoding EAAT1 or EAAT2 was injected into Xenopus oocytes without or with additional injection of cRNA encoding wild-type SPAK or wild-type OSR1, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 or catalytically inactive (D164A)OSR1. The glutamate (2 mM)-induced inward current (I Glu) was taken as a measure of glutamate transport. As a result, I Glu was observed in EAAT1- and in EAAT2-expressing oocytes but not in water-injected oocytes, and was significantly decreased by coexpression of SPAK and OSR1. As shown for EAAT2, SPAK, and OSR1 decreased significantly the maximal transport rate but significantly enhanced the affinity of the carrier. The effect of wild-type SPAK/OSR1 on EAAT1 and EAAT2 was mimicked by (T233E)SPAK and (T185E)OSR1, but not by (T233A)SPAK, (D212A)SPAK, (T185A)OSR1, or (D164A)OSR1. Coexpression of either SPAK or OSR1 decreased the EAAT2 protein abundance in the cell membrane of EAAT2-expressing oocytes. In conclusion, SPAK and OSR1 are powerful negative regulators of the excitatory glutamate transporters EAAT1 and EAAT2.
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Affiliation(s)
- Abeer Abousaab
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Jamshed Warsi
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Bernat Elvira
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Ioana Alesutan
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Zohreh Hoseinzadeh
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Florian Lang
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany.
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10
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Borrás J, Salker MS, Elvira B, Warsi J, Fezai M, Hoseinzadeh Z, Lang F. SPAK and OSR1 Sensitivity of Excitatory Amino Acid Transporter EAAT3. Nephron Clin Pract 2015; 130:221-8. [PMID: 26112741 DOI: 10.1159/000433567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/20/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Kinases involved in the regulation of epithelial transport include SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1). SPAK and OSR1 are both regulated by WNK (with-no-K(Lys)) kinases. The present study explored whether SPAK and/or OSR1 influence the excitatory amino acid transporter EAAT3, which accomplishes glutamate and aspartate transport in kidney, intestine and brain. METHODS cRNA encoding EAAT3 was injected into Xenopus laevis oocytes with or without additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 and catalytically inactive (D164A)OSR1. Glutamate-induced current was taken as measure of electrogenic glutamate transport and was quantified utilizing dual electrode voltage clamp. Furthermore, Ussing chamber was employed to determine glutamate transport in the intestine from gene-targeted mice carrying WNK insensitive SPAK (spak(tg/tg)) and from corresponding wild-type mice (spak(+/+)). RESULTS EAAT3 activity was significantly decreased by wild-type SPAK and (T233E)SPAK, but not by (T233A)SPAK and (D212A)SPAK. SPAK decreased maximal transport rate without affecting significantly affinity of the carrier. Similarly, EAAT3 activity was significantly downregulated by wild-type OSR1 and (T185E)OSR1, but not by (T185A)OSR1 and (D164A)OSR1. Again OSR1 decreased maximal transport rate without affecting significantly affinity of the carrier. Intestinal electrogenic glutamate transport was significantly lower in spak(+/+) than in spak(tg/tg) mice. CONCLUSION Both, SPAK and OSR1 are negative regulators of EAAT3 activity.
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Affiliation(s)
- José Borrás
- Department of Physiology I, University of Tübingen, Tubingen, Germany
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Warsi J, Elvira B, Bissinger R, Hosseinzadeh Z, Lang F. Regulation of Voltage-Gated K+ Channel Kv1.5 by the Janus Kinase JAK3. J Membr Biol 2015; 248:1061-70. [PMID: 26100849 DOI: 10.1007/s00232-015-9817-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 06/08/2015] [Indexed: 01/30/2023]
Abstract
The tyrosine kinase Janus kinase 3 (JAK3) participates in the regulation of cell proliferation and apoptosis. The kinase further influences ion channels and transport proteins. The present study explored whether JAK3 contributes to the regulation of the voltage-gated K(+) channel Kv1.5, which participates in the regulation of diverse functions including atrial cardiac action potential and tumor cell proliferation. To this end, cRNA encoding Kv1.5 was injected into Xenopus oocytes with or without additional injection of cRNA encoding wild-type JAK3, constitutively active (A568V)JAK3, or inactive (K851A)JAK3. Voltage-gated K(+) channel activity was measured utilizing dual electrode voltage clamp, and Kv1.5 channel protein abundance in the cell membrane was quantified utilizing chemiluminescence of Kv1.5 containing an extracellular hemagglutinin epitope (Kv1.5-HA). As a result, Kv1.5 activity and Kv1.5-HA protein abundance were significantly decreased by wild-type JAK3 and (A568V)JAK3, but not by (K851A)JAK3. Inhibition of Kv1.5 protein insertion into the cell membrane by brefeldin A (5 μM) resulted in a decline of the voltage-gated current, which was similar in the absence and presence of (A568V)JAK3, suggesting that (A568V)JAK3 did not accelerate Kv1.5 protein retrieval from the cell membrane. A 24 h treatment with ouabain (100 µM) significantly decreased the voltage-gated current in oocytes expressing Kv1.5 without or with (A568V)JAK3 and dissipated the difference between oocytes expressing Kv1.5 alone and oocytes expressing Kv1.5 with (A568V)JAK3. In conclusion, JAK3 contributes to the regulation of membrane Kv1.5 protein abundance and activity, an effect sensitive to ouabain and thus possibly involving Na(+)/K(+) ATPase activity.
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Affiliation(s)
- Jamshed Warsi
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Bernat Elvira
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Rosi Bissinger
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Zohreh Hosseinzadeh
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Florian Lang
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany.
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USP18 Sensitivity of Peptide Transporters PEPT1 and PEPT2. PLoS One 2015; 10:e0129365. [PMID: 26046984 PMCID: PMC4457862 DOI: 10.1371/journal.pone.0129365] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 05/07/2015] [Indexed: 11/20/2022] Open
Abstract
USP18 (Ubiquitin-like specific protease 18) is an enzyme cleaving ubiquitin from target proteins. USP18 plays a pivotal role in antiviral and antibacterial immune responses. On the other hand, ubiquitination participates in the regulation of several ion channels and transporters. USP18 sensitivity of transporters has, however, never been reported. The present study thus explored, whether USP18 modifies the activity of the peptide transporters PEPT1 and PEPT2, and whether the peptide transporters are sensitive to the ubiquitin ligase Nedd4-2. To this end, cRNA encoding PEPT1 or PEPT2 was injected into Xenopus laevis oocytes without or with additional injection of cRNA encoding USP18. Electrogenic peptide (glycine-glycine) transport was determined by dual electrode voltage clamp. As a result, in Xenopus laevis oocytes injected with cRNA encoding PEPT1 or PEPT2, but not in oocytes injected with water or with USP18 alone, application of the dipeptide gly-gly (2 mM) was followed by the appearance of an inward current (Igly-gly). Coexpression of USP18 significantly increased Igly-gly in both PEPT1 and PEPT2 expressing oocytes. Kinetic analysis revealed that coexpression of USP18 increased maximal Igly-gly. Conversely, overexpression of the ubiquitin ligase Nedd4-2 decreased Igly-gly. Coexpression of USP30 similarly increased Igly-gly in PEPT1 expressing oocytes. In conclusion, USP18 sensitive cellular functions include activity of the peptide transporters PEPT1 and PEPT2.
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Almilaji A, Honisch S, Liu G, Elvira B, Ajay SS, Hosseinzadeh Z, Ahmed M, Munoz C, Sopjani M, Lang F. Regulation of the voltage gated K channel Kv1.3 by recombinant human klotho protein. Kidney Blood Press Res 2014; 39:609-22. [PMID: 25571875 DOI: 10.1159/000368472] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Klotho, a protein mainly produced in the kidney and released into circulating blood, contributes to the negative regulation of 1,25(OH)2D3 formation and is thus a powerful regulator of mineral metabolism. As β-glucuronidase, alpha Klotho protein further regulates the stability of several carriers and channels in the plasma membrane and thus regulates channel and transporter activity. Accordingly, alpha Klotho protein participates in the regulation of diverse functions seemingly unrelated to mineral metabolism including lymphocyte function. The present study explored the impact of alpha Klotho protein on the voltage gated K+ channel Kv1.3. METHODS cRNA encoding Kv1.3 (KCNA3) was injected into Xenopus oocytes and depolarization induced outward current in Kv1.3 expressing Xenopus oocytes determined utilizing dual electrode voltage clamp. Experiments were performed without or with prior treatment with recombinant human Klotho protein (50 ng/ml, 24 hours) in the absence or presence of a β-glucuronidase inhibitor D-saccharic acid-1,4-lactone (DSAL, 10 µM). Moreover, the voltage gated K+ current was determined in Jcam lymphoma cells by whole cell patch clamp following 24 hours incubation without or with recombinant human Klotho protein (50 ng/ml, 24 hours). Kv1.3 protein abundance in Jcam cells was determined utilising fluorescent antibodies in flow cytometry. RESULTS In Kv1.3 expressing Xenopus oocytes the Kv1.3 currents and the protein abundance of Kv1.3 were both significantly enhanced after treatment with recombinant human Klotho protein (50 ng/ml, 24 hours), an effect reversed by presence of DSAL. Moreover, treatment with recombinant human Klotho protein increased Kv currents and Kv1.3 protein abundance in Jcam cells. CONCLUSION Alpha Klotho protein enhances Kv1.3 channel abundance and Kv1.3 currents in the plasma membrane, an effect depending on its β-glucuronidase activity.
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Affiliation(s)
- Ahmad Almilaji
- Department of Physiology, University of Tübingen, Tübingen, Germany
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