1
|
Song HC, Zhang Y, Ma ZX, Yao QL, Ma XJ. TWIK-related acid-sensitive potassium channels TASK-1 and TASK-3 may participate in the process of the coexistence of asthma and OSA. Sleep Breath 2024; 28:123-131. [PMID: 37428352 DOI: 10.1007/s11325-023-02869-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 05/27/2023] [Accepted: 06/02/2023] [Indexed: 07/11/2023]
Abstract
OBJECTIVE To investigate the role of TWIK-related acid-sensitive potassium channels TASK-1 and TASK-3 in the mechanism of asthma combined with obstructive sleep apnea (OSA) in mice. METHOD C57BL/6 mice were randomly divided into four groups: control group (NS-RA), asthma group (OVA-RA), OSA group (NS-IH), and asthma combined with OSA group (OVA-IH). After monitoring lung function in each group, the expression levels of TASK-1 and TASK-3 mRNA and protein in lung tissues were measured, and the correlation between the changes of both and lung function was analyzed. RESULTS A total of 64 male mice were studied. Penh, serum IgE concentrations, and the percentage of eosinophils in bronchoalveolar lavage fluid (BALF) were higher in OVA-RA and OVA-IH mice compared with NS-RA (P < 0.05),while the above indexes were slightly elevated in NS-IH mice compared with NS-RA (P > 0.05), where the Penh and the percentage of eosinophils in BALF was higher in OVA-IH mice than NS-IH (P < 0.05).Increased TASK-3 mRNA expression (P < 0.05) as well as TASK-1 and TASK-3 protein expression (P > 0.05) in lung tissues of OVA-RA and NS-IH mice compared with NS-RA, and TASK-3 mRNA expression was slightly more in the OVA-IH group compared with NS-RA (P > 0.05), but less compared with OVA-RA (P < 0.05) or NS-IH (P > 0.05), while TASK-1 and TASK-3 protein expression was increased in the OVA-IH group compared with the remaining three groups, and TASK-3 protein expression was associated with lung function impairment was positively correlated with the degree of lung function impairment (P < 0.05). CONCLUSION Task-1 and Task-3 may be involved in the pathogenesis of asthma with OSA by affecting lung function.
Collapse
Affiliation(s)
- Hai-Chen Song
- First Department of Internal Pediatrics, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Xinjiang Key Laboratory of Molecular Biology for Endemic Diseases, Xinjiang, 830011, China
| | - Yan Zhang
- Department of Pathophysiology, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Zhi-Xing Ma
- Emergency Department, Changji Prefecture People's Hospital, Changji, 831100, Xinjiang, China
| | - Qiao-Lin Yao
- Department of Physiology, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China.
| | - Xiao-Juan Ma
- Department of Pathophysiology, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China.
| |
Collapse
|
2
|
Byrne DP, Omar MH, Kennedy EJ, Eyers PA, Scott JD. Biochemical Analysis of AKAP-Anchored PKA Signaling Complexes. Methods Mol Biol 2022; 2483:297-317. [PMID: 35286684 PMCID: PMC9518671 DOI: 10.1007/978-1-0716-2245-2_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Generation of the prototypic second messenger cAMP instigates numerous signaling events. A major intracellular target of cAMP is Protein kinase A (PKA), a Ser/Thr protein kinase. Where and when this enzyme is activated inside the cell has profound implications on the functional impact of PKA. It is now well established that PKA signaling is focused locally into subcellular signaling "islands" or "signalosomes." The A-Kinase Anchoring Proteins (AKAPs) play a critical role in this process by dictating spatial and temporal aspects of PKA action. Genetically encoded biosensors, small molecule and peptide-based disruptors of PKA signaling are valuable tools for rigorous investigation of local PKA action at the biochemical level. This chapter focuses on approaches to evaluate PKA signaling islands, including a simple assay for monitoring the interaction of an AKAP with a tunable PKA holoenzyme. The latter approach evaluates the composition of PKA holoenzymes, in which regulatory subunits and catalytic subunits can be visualized in the presence of test compounds and small-molecule inhibitors.
Collapse
Affiliation(s)
- Dominic P Byrne
- Department of Biochemistry and Systems Biology, ISMIB, University of Liverpool, Liverpool, UK
| | - Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, USA
| | - Patrick A Eyers
- Department of Biochemistry and Systems Biology, ISMIB, University of Liverpool, Liverpool, UK.
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, WA, USA.
| |
Collapse
|
3
|
TASK channels: channelopathies, trafficking, and receptor-mediated inhibition. Pflugers Arch 2020; 472:911-922. [DOI: 10.1007/s00424-020-02403-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/08/2020] [Accepted: 05/18/2020] [Indexed: 01/06/2023]
|
4
|
Ohya S, Kito H, Hatano N, Muraki K. Recent advances in therapeutic strategies that focus on the regulation of ion channel expression. Pharmacol Ther 2016; 160:11-43. [PMID: 26896566 DOI: 10.1016/j.pharmthera.2016.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A number of different ion channel types are involved in cell signaling networks, and homeostatic regulatory mechanisms contribute to the control of ion channel expression. Profiling of global gene expression using microarray technology has recently provided novel insights into the molecular mechanisms underlying the homeostatic and pathological control of ion channel expression. It has demonstrated that the dysregulation of ion channel expression is associated with the pathogenesis of neural, cardiovascular, and immune diseases as well as cancers. In addition to the transcriptional, translational, and post-translational regulation of ion channels, potentially important evidence on the mechanisms controlling ion channel expression has recently been accumulated. The regulation of alternative pre-mRNA splicing is therefore a novel therapeutic strategy for the treatment of dominant-negative splicing disorders. Epigenetic modification plays a key role in various pathological conditions through the regulation of pluripotency genes. Inhibitors of pre-mRNA splicing and histone deacetyalase/methyltransferase have potential as potent therapeutic drugs for cancers and autoimmune and inflammatory diseases. Moreover, membrane-anchoring proteins, lysosomal and proteasomal degradation-related molecules, auxiliary subunits, and pharmacological agents alter the protein folding, membrane trafficking, and post-translational modifications of ion channels, and are linked to expression-defect channelopathies. In this review, we focused on recent insights into the transcriptional, spliceosomal, epigenetic, and proteasomal regulation of ion channel expression: Ca(2+) channels (TRPC/TRPV/TRPM/TRPA/Orai), K(+) channels (voltage-gated, KV/Ca(2+)-activated, KCa/two-pore domain, K2P/inward-rectifier, Kir), and Ca(2+)-activated Cl(-) channels (TMEM16A/TMEM16B). Furthermore, this review highlights expression of these ion channels in expression-defect channelopathies.
Collapse
Affiliation(s)
- Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Hiroaki Kito
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Noriyuki Hatano
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan
| | - Katsuhiko Muraki
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan.
| |
Collapse
|
5
|
Kilisch M, Lytovchenko O, Arakel EC, Bertinetti D, Schwappach B. A dual phosphorylation switch controls 14-3-3-dependent cell surface expression of TASK-1. J Cell Sci 2016; 129:831-42. [PMID: 26743085 PMCID: PMC4760375 DOI: 10.1242/jcs.180182] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/29/2015] [Indexed: 11/20/2022] Open
Abstract
The transport of the K+ channels TASK-1 and TASK-3 (also known as KCNK3 and KCNK9, respectively) to the cell surface is controlled by the binding of 14-3-3 proteins to a trafficking control region at the extreme C-terminus of the channels. The current model proposes that phosphorylation-dependent binding of 14-3-3 sterically masks a COPI-binding motif. However, the direct effects of phosphorylation on COPI binding and on the binding parameters of 14-3-3 isoforms are still unknown. We find that phosphorylation of the trafficking control region prevents COPI binding even in the absence of 14-3-3, and we present a quantitative analysis of the binding of all human 14-3-3 isoforms to the trafficking control regions of TASK-1 and TASK-3. Surprisingly, the affinities of 14-3-3 proteins for TASK-1 are two orders of magnitude lower than for TASK-3. Furthermore, we find that phosphorylation of a second serine residue in the C-terminus of TASK-1 inhibits 14-3-3 binding. Thus, phosphorylation of the trafficking control region can stimulate or inhibit transport of TASK-1 to the cell surface depending on the target serine residue. Our findings indicate that control of TASK-1 trafficking by COPI, kinases, phosphatases and 14-3-3 proteins is highly dynamic. Summary: Phosphorylation of a previously neglected serine residue in the trafficking control region of TASK-1 interferes with the binding of trafficking machinery and enables complex regulation by physiological stimuli.
Collapse
Affiliation(s)
- Markus Kilisch
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany
| | - Olga Lytovchenko
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany
| | - Eric C Arakel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany
| | | | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany Max-Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
| |
Collapse
|
6
|
Renigunta V, Schlichthörl G, Daut J. Much more than a leak: structure and function of K₂p-channels. Pflugers Arch 2015; 467:867-94. [PMID: 25791628 DOI: 10.1007/s00424-015-1703-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 11/27/2022]
Abstract
Over the last decade, we have seen an enormous increase in the number of experimental studies on two-pore-domain potassium channels (K2P-channels). The collection of reviews and original articles compiled for this special issue of Pflügers Archiv aims to give an up-to-date summary of what is known about the physiology and pathophysiology of K2P-channels. This introductory overview briefly describes the structure of K2P-channels and their function in different organs. Its main aim is to provide some background information for the 19 reviews and original articles of this special issue of Pflügers Archiv. It is not intended to be a comprehensive review; instead, this introductory overview focuses on some unresolved questions and controversial issues, such as: Do K2P-channels display voltage-dependent gating? Do K2P-channels contribute to the generation of action potentials? What is the functional role of alternative translation initiation? Do K2P-channels have one or two or more gates? We come to the conclusion that we are just beginning to understand the extremely complex regulation of these fascinating channels, which are often inadequately described as 'leak channels'.
Collapse
Affiliation(s)
- Vijay Renigunta
- Institute of Physiology and Pathophysiology, Marburg University, 35037, Marburg, Germany
| | | | | |
Collapse
|
7
|
The role of protein-protein interactions in the intracellular traffic of the potassium channels TASK-1 and TASK-3. Pflugers Arch 2015; 467:1105-20. [PMID: 25559843 DOI: 10.1007/s00424-014-1672-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
Abstract
The intracellular transport of membrane proteins is controlled by trafficking signals: Short peptide motifs that mediate the contact with COPI, COPII or various clathrin-associated coat proteins. In addition, many membrane proteins interact with accessory proteins that are involved in the sorting of these proteins to different intracellular compartments. In the K2P channels, TASK-1 and TASK-3, the influence of protein-protein interactions on sorting decisions has been studied in some detail. Both TASK paralogues interact with the adaptor protein 14-3-3; TASK-1 interacts, in addition, with the adaptor protein p11 (S100A10) and the endosomal SNARE protein syntaxin-8. The role of these interacting proteins in controlling the intracellular traffic of the channels and the underlying molecular mechanisms are summarised in this review. In the case of 14-3-3, the interacting protein masks a retention signal in the C-terminus of the channel; in the case of p11, the interacting protein carries a retention signal that localises the channel to the endoplasmic reticulum; and in the case of syntaxin-8, the interacting protein carries an endocytosis signal that complements an endocytosis signal of the channel. These examples illustrate some of the mechanisms by which interacting proteins may determine the itinerary of a membrane protein within a cell and suggest that the intracellular traffic of membrane proteins may be adapted to the specific functions of that protein by multiple protein-protein interactions.
Collapse
|
8
|
Liu F, Zhou Q, Zhou J, Sun H, Wang Y, Zou X, Feng L, Hou Z, Zhou A, Zhou Y, Li Y. 14-3-3τ promotes surface expression of Cav2.2 (α1B) Ca2+ channels. J Biol Chem 2014; 290:2689-98. [PMID: 25516596 DOI: 10.1074/jbc.m114.567800] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Surface expression of voltage-gated Ca(2+) (Cav) channels is important for their function in calcium homeostasis in the physiology of excitable cells, but whether or not and how the α1 pore-forming subunits of Cav channels are trafficked to plasma membrane in the absence of the known Cav auxiliary subunits, β and α2δ, remains mysterious. Here we showed that 14-3-3 proteins promoted functional surface expression of the Cav2.2 α1B channel in transfected tsA-201 cells in the absence of any known Cav auxiliary subunit. Both the surface to total ratio of the expressed α1B protein and the current density of voltage step-evoked Ba(2+) current were markedly suppressed by the coexpression of a 14-3-3 antagonist construct, pSCM138, but not its inactive control, pSCM174, as determined by immunofluorescence assay and whole cell voltage clamp recording, respectively. By contrast, coexpression with 14-3-3τ significantly enhanced the surface expression and current density of the Cav2.2 α1B channel. Importantly, we found that between the two previously identified 14-3-3 binding regions at the α1B C terminus, only the proximal region (amino acids 1706-1940), closer to the end of the last transmembrane domain, was retained by the endoplasmic reticulum and facilitated by 14-3-3 to traffic to plasma membrane. Additionally, we showed that the 14-3-3/Cav β subunit coregulated the surface expression of Cav2.2 channels in transfected tsA-201 cells and neurons. Altogether, our findings reveal a previously unidentified regulatory function of 14-3-3 proteins in promoting the surface expression of Cav2.2 α1B channels.
Collapse
Affiliation(s)
- Feng Liu
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Qin Zhou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Jie Zhou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Hao Sun
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Yan Wang
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Xiuqun Zou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Lingling Feng
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Zhaoyuan Hou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Aiwu Zhou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Yi Zhou
- the Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306
| | - Yong Li
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| |
Collapse
|
9
|
Arakel EC, Brandenburg S, Uchida K, Zhang H, Lin YW, Kohl T, Schrul B, Sulkin MS, Efimov IR, Nichols CG, Lehnart SE, Schwappach B. Tuning the electrical properties of the heart by differential trafficking of KATP ion channel complexes. J Cell Sci 2014; 127:2106-19. [PMID: 24569881 PMCID: PMC4004980 DOI: 10.1242/jcs.141440] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The copy number of membrane proteins at the cell surface is tightly regulated. Many ion channels and receptors present retrieval motifs to COPI vesicle coats and are retained in the early secretory pathway. In some cases, the interaction with COPI is prevented by binding to 14-3-3 proteins. However, the functional significance of this antagonism between COPI and 14-3-3 in terminally differentiated cells is unknown. Here, we show that ATP-sensitive K+ (KATP) channels, which are composed of Kir6.2 and SUR1 subunits, are stalled in the Golgi complex of ventricular, but not atrial, cardiomyocytes. Upon sustained β-adrenergic stimulation, which leads to activation of protein kinase A (PKA), SUR1-containing channels reach the plasma membrane of ventricular cells. We show that PKA-dependent phosphorylation of the C-terminus of Kir6.2 decreases binding to COPI and, thereby, silences the arginine-based retrieval signal. Thus, activation of the sympathetic nervous system releases this population of KATP channels from storage in the Golgi and, hence, might facilitate the adaptive response to metabolic challenges.
Collapse
Affiliation(s)
- Eric C Arakel
- Department of Molecular Biology, Center for Biochemistry and Molecular Cell Biology, Heart Research Center Göttingen, University Medicine Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Angiotensin (1-7) increases the potassium current and the resting potential of arterial myocytes from vascular resistance vessels of normal adult rats: Pathophysiological implications. ACTA ACUST UNITED AC 2013; 8:14-20. [PMID: 24220548 DOI: 10.1016/j.jash.2013.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 08/20/2013] [Indexed: 11/21/2022]
Abstract
The influence of angiotensin (Ang) (1-7) on potassium current (Kv) and resting potential of smooth muscle cells isolated from mesenteric artery of Sprague Dawley rats was investigated. Measurements of potassium current were performed using the whole cell configuration of pCLAMP. The results indicated that Ang (1-7) (10(-9) M) increased the potassium current by 120% ± 2.6% (P < .05) and the resting potential of smooth muscle cells by 8 ± 2.8 mV (n = 23; P < .05). Ang II (10(-9) M) administered to the bath reduced the potassium current by 35% ± 3.6% (n = 23; P < .05) and depolarized the arterial myocytes by 7.8 ± 2.1 mV (n = 25; P < .05). The effect of the heptapeptide on potassium current was inhibited by a Mas receptor inhibitor (A779; 10(-8) M) as well as by a protein kinase A (PKA) inhibitor (10(-9) M) dialyzed into the cell. Intracellular dialysis of the catalytic subunit of PKA (5 × 10(-8) M) enhanced the potassium current by 38% ± 3.4% (n = 14; P < .05) but did not abolish the effect of Ang (1-7). On the other hand, Bis-1 (10(-9) M), which is a specific inhibitor of PKC, suppressed the effect of Ang (1-7) on potassium current. In conclusion, Ang (1-7) counteracts the effect of Ang II on potassium current and membrane potential of smooth muscle cells from mesenteric arteries, which are resistance vessels involved in the regulation of peripheral resistance and blood pressure. The activation of the cAMP/PKA cascade is essential for the effect of the heptapeptide. Pathophysiological implications are discussed.
Collapse
|
11
|
Chatelain FC, Bichet D, Feliciangeli S, Larroque MM, Braud VM, Douguet D, Lesage F. Silencing of the tandem pore domain halothane-inhibited K+ channel 2 (THIK2) relies on combined intracellular retention and low intrinsic activity at the plasma membrane. J Biol Chem 2013; 288:35081-92. [PMID: 24163367 DOI: 10.1074/jbc.m113.503318] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The tandem pore domain halothane-inhibited K(+) channel 1 (THIK1) produces background K(+) currents. Despite 62% amino acid identity with THIK1, THIK2 is not active upon heterologous expression. Here, we show that this apparent lack of activity is due to a unique combination of retention in the endoplasmic reticulum and low intrinsic channel activity at the plasma membrane. A THIK2 mutant containing a proline residue (THIK2-A155P) in its second inner helix (M2) produces K(+)-selective currents with properties similar to THIK1, including inhibition by halothane and insensitivity to extracellular pH variations. Another mutation in the M2 helix (I158D) further increases channel activity and affects current kinetics. We also show that the cytoplasmic amino-terminal region of THIK2 (Nt-THIK2) contains an arginine-rich motif (RRSRRR) that acts as a retention/retrieval signal. Mutation of this motif in THIK2 induces a relocation of the channel to the plasma membrane, resulting in measurable currents, even in the absence of mutations in the M2 helix. Cell surface delivery of a Nt-THIK2-CD161 chimera is increased by mutating the arginines of the retention motif but also by converting the serine embedded in this motif to aspartate, suggesting a phosphorylation-dependent regulation of THIK2 trafficking.
Collapse
Affiliation(s)
- Franck C Chatelain
- From the Laboratory of Excellence Ion Channel Science and Therapeutics, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, and Université de Nice Sophia Antipolis, 660 Route des Lucioles, 06560 Valbonne, France
| | | | | | | | | | | | | |
Collapse
|
12
|
Mant A, Williams S, O'Kelly I. Acid sensitive background potassium channels K2P3.1 and K2P9.1 undergo rapid dynamin-dependent endocytosis. Channels (Austin) 2013; 7:288-302. [PMID: 23807092 DOI: 10.4161/chan.25120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Acid-sensitive, two-pore domain potassium channels, K(2P)3.1 and K(2P)9.1, are implicated in cardiac and nervous tissue responses to hormones, neurotransmitters and drugs. K(2P)3.1 and K(2P)9.1 leak potassium from the cell at rest and directly impact membrane potential. Hence altering channel number on the cell surface drives changes in cellular electrical properties. The rate of K(2P)3.1 and K(2P)9.1 delivery to and recovery from the plasma membrane determines both channel number at the cell surface and potassium leak from cells. This study examines the endocytosis of K(2P)3.1 and K(2P)9.1. Plasma membrane biotinylation was used to follow the fate of internalized GFP-tagged rat K(2P)3.1 and K(2P)9.1 transiently expressed in HeLa cells. Confocal fluorescence images were analyzed using Imaris software, which revealed that both channels are endocytosed by a dynamin-dependent mechanism and over the course of 60 min, move progressively toward the nucleus. Endogenous endocytosis of human K(2P)3.1 and K(2P)9.1 was examined in the lung carcinoma cell line, A549. Endogenous channels are endocytosed over a similar time-scale to the channels expressed transiently in HeLa cells. These findings both validate the use of recombinant systems and identify an endogenous model system in which K(2P)3.1 and K(2P)9.1 trafficking can be further studied.
Collapse
Affiliation(s)
- Alexandra Mant
- Human Development and Health; Centre for Human Development, Stem Cells and Regeneration; Faculty of Medicine; University of Southampton; Southampton, UK
| | | | | |
Collapse
|
13
|
Chou MF, Prisic S, Lubner JM, Church GM, Husson RN, Schwartz D. Using bacteria to determine protein kinase specificity and predict target substrates. PLoS One 2012; 7:e52747. [PMID: 23300758 PMCID: PMC3530509 DOI: 10.1371/journal.pone.0052747] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 11/21/2012] [Indexed: 11/18/2022] Open
Abstract
The identification of protein kinase targets remains a significant bottleneck for our understanding of signal transduction in normal and diseased cellular states. Kinases recognize their substrates in part through sequence motifs on substrate proteins, which, to date, have most effectively been elucidated using combinatorial peptide library approaches. Here, we present and demonstrate the ProPeL method for easy and accurate discovery of kinase specificity motifs through the use of native bacterial proteomes that serve as in vivo libraries for thousands of simultaneous phosphorylation reactions. Using recombinant kinases expressed in E. coli followed by mass spectrometry, the approach accurately recapitulated the well-established motif preferences of human basophilic (Protein Kinase A) and acidophilic (Casein Kinase II) kinases. These motifs, derived for PKA and CK II using only bacterial sequence data, were then further validated by utilizing them in conjunction with the scan-x software program to computationally predict known human phosphorylation sites with high confidence.
Collapse
Affiliation(s)
- Michael F. Chou
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sladjana Prisic
- Division of Infectious Diseases, Children’s Hospital Boston and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Joshua M. Lubner
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, United States of America
| | - George M. Church
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Robert N. Husson
- Division of Infectious Diseases, Children’s Hospital Boston and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Daniel Schwartz
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, United States of America
- * E-mail:
| |
Collapse
|
14
|
Mant A, Williams S, Roncoroni L, Lowry E, Johnson D, O'Kelly I. N-glycosylation-dependent control of functional expression of background potassium channels K2P3.1 and K2P9.1. J Biol Chem 2012; 288:3251-64. [PMID: 23250752 DOI: 10.1074/jbc.m112.405167] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Two-pore domain potassium (K(2P)) channels play fundamental roles in cellular processes by enabling a constitutive leak of potassium from cells in which they are expressed, thus influencing cellular membrane potential and activity. Hence, regulation of these channels is of critical importance to cellular function. A key regulatory mechanism of K(2P) channels is the control of their cell surface expression. Membrane protein delivery to and retrieval from the cell surface is controlled by their passage through the secretory and endocytic pathways, and post-translational modifications regulate their progression through these pathways. All but one of the K(2P) channels possess consensus N-linked glycosylation sites, and here we demonstrate that the conserved putative N-glycosylation site in K(2P)3.1 and K(2P)9.1 is a glycan acceptor site. Patch clamp analysis revealed that disruption of channel glycosylation reduced K(2P)3.1 current, and flow cytometry was instrumental in attributing this to a decreased number of channels on the cell surface. Similar findings were observed when cells were cultured in reduced glucose concentrations. Disruption of N-linked glycosylation has less of an effect on K(2P)9.1, with a small reduction in number of channels on the surface observed, but no functional implications detected. Because nonglycosylated channels appear to pass through the secretory pathway in a manner comparable with glycosylated channels, the evidence presented here suggests that the decreased number of nonglycosylated K(2P)3.1 channels on the cell surface may be due to their decreased stability.
Collapse
Affiliation(s)
- Alexandra Mant
- Human Development and Health, Centre for Human Development, Stem Cells and Regeneration, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | | | | | | | | | | |
Collapse
|
15
|
Guo Y, Wilderman A, Zhang L, Taylor SS, Insel PA. Quantitative proteomics analysis of the cAMP/protein kinase A signaling pathway. Biochemistry 2012; 51:9323-32. [PMID: 23110364 PMCID: PMC3503394 DOI: 10.1021/bi301282k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
To define the proteins whose expression is regulated
by cAMP and
protein kinase A (PKA), we used a quantitative proteomics approach
in studies of wild-type (WT) and kin- (PKA-null) S49 murine T lymphoma
cells. We also compared the impact of endogenous increases in the
level of cAMP [by forskolin (Fsk) and the phosphodiesterase inhibitor
isobutylmethylxanthine (IBMX)] or by a cAMP analogue (8-CPT-cAMP).
We identified 1056 proteins in WT and kin- S49 cells and found that
8-CPT-cAMP and Fsk with IBMX produced differences in protein expression.
WT S49 cells had a correlation coefficient of 0.41 between DNA microarray
data and the proteomics analysis in cells incubated with 8-CPT-cAMP
for 24 h and a correlation coefficient of 0.42 between the DNA microarray
data obtained at 6 h and the changes in protein expression after incubation
with 8-CPT-cAMP for 24 h. Glutathione reductase (Gsr) had a higher
level of basal expression in kin- S49 cells than in WT cells. Consistent
with this finding, kin- cells are less sensitive to cell killing and
generation of malondialdehyde than are WT cells incubated with H2O2. Cyclic AMP acting via PKA thus has a broad
impact on protein expression in mammalian cells, including in the
regulation of Gsr and oxidative stress.
Collapse
Affiliation(s)
- Yurong Guo
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92093-0654, United States
| | | | | | | | | |
Collapse
|
16
|
Rahm AK, Gierten J, Kisselbach J, Staudacher I, Staudacher K, Schweizer PA, Becker R, Katus HA, Thomas D. PKC-dependent activation of human K(2P) 18.1 K(+) channels. Br J Pharmacol 2012; 166:764-73. [PMID: 22168364 DOI: 10.1111/j.1476-5381.2011.01813.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Two-pore-domain K(+) channels (K(2P) ) mediate K(+) background currents that modulate the membrane potential of excitable cells. K(2P) 18.1 (TWIK-related spinal cord K(+) channel) provides hyperpolarizing background currents in neurons. Recently, a dominant-negative loss-of-function mutation in K(2P) 18.1 has been implicated in migraine, and activation of K(2P) 18.1 channels was proposed as a therapeutic strategy. Here we elucidated the molecular mechanisms underlying PKC-dependent activation of K(2P) 18.1 currents. EXPERIMENTAL APPROACH Human K(2P) 18.1 channels were heterologously expressed in Xenopus laevis oocytes, and currents were recorded with the two-electrode voltage clamp technique. KEY RESULTS Stimulation of PKC using phorbol 12-myristate-13-acetate (PMA) activated the hK(2P) 18.1 current by 3.1-fold in a concentration-dependent fashion. The inactive analogue 4α-PMA had no effect on channel activity. The specific PKC inhibitors bisindolylmaleimide I, Ro-32-0432 and chelerythrine reduced PMA-induced channel activation indicating that PKC is involved in this effect of PMA. Selective activation of conventional PKC isoforms with thymeleatoxin (100 nM) did not reproduce K(2P) 18.1 channel activation. Current activation by PMA was not affected by pretreatment with CsA (calcineurin inhibitor) or KT 5720 (PKA inhibitor), ruling out a significant contribution of calcineurin or cross-talk with PKA to the PKC-dependent hK(2P) 18.1 activation. Finally, mutation of putative PKC phosphorylation sites did not prevent PMA-induced K(2P) 18.1 channel activation. CONCLUSIONS AND IMPLICATIONS We demonstrated that activation of hK(2P) 18.1 (TRESK) by PMA is mediated by PKC stimulation. Hence, PKC-mediated activation of K(2P) 18.1 background currents may serve as a novel molecular target for migraine treatment.
Collapse
Affiliation(s)
- Ann-Kathrin Rahm
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Gabriel L, Lvov A, Orthodoxou D, Rittenhouse AR, Kobertz WR, Melikian HE. The acid-sensitive, anesthetic-activated potassium leak channel, KCNK3, is regulated by 14-3-3β-dependent, protein kinase C (PKC)-mediated endocytic trafficking. J Biol Chem 2012; 287:32354-66. [PMID: 22846993 DOI: 10.1074/jbc.m112.391458] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The acid-sensitive neuronal potassium leak channel, KCNK3, is vital for setting the resting membrane potential and is the primary target for volatile anesthetics. Recent reports demonstrate that KCNK3 activity is down-regulated by PKC; however, the mechanisms responsible for PKC-induced KCNK3 down-regulation are undefined. Here, we report that endocytic trafficking dynamically regulates KCNK3 activity. Phorbol esters and Group I metabotropic glutamate receptor (mGluR) activation acutely decreased both native and recombinant KCNK3 currents with concomitant KCNK3 surface losses in cerebellar granule neurons and cell lines. PKC-mediated KCNK3 internalization required the presence of both 14-3-3β and a novel potassium channel endocytic motif, because depleting either 14-3-3β protein levels or ablating the endocytic motif completely abrogated PKC-regulated KCNK3 trafficking. These results demonstrate that neuronal potassium leak channels are not static membrane residents but are subject to 14-3-3β-dependent regulated trafficking, providing a straightforward mechanism to modulate neuronal excitability and synaptic plasticity by Group I mGluRs.
Collapse
Affiliation(s)
- Luke Gabriel
- Graduate Program in Neuroscience, University of Massachusetts Medical School, Worcester, Massachusetts 01604, USA
| | | | | | | | | | | |
Collapse
|
18
|
Jimenez V, Docampo R. Molecular and electrophysiological characterization of a novel cation channel of Trypanosoma cruzi. PLoS Pathog 2012; 8:e1002750. [PMID: 22685407 PMCID: PMC3369953 DOI: 10.1371/journal.ppat.1002750] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 04/27/2012] [Indexed: 01/27/2023] Open
Abstract
We report the identification, functional expression, purification, reconstitution and electrophysiological characterization of a novel cation channel (TcCat) from Trypanosoma cruzi, the etiologic agent of Chagas disease. This channel is potassium permeable and shows inward rectification in the presence of magnesium. Western blot analyses with specific antibodies indicated that the protein is expressed in the three main life cycle stages of the parasite. Surprisingly, the parasites have the unprecedented ability to rapidly change the localization of the channel when they are exposed to different environmental stresses. TcCat rapidly translocates to the tip of the flagellum when trypomastigotes are submitted to acidic pH, to the plasma membrane when epimastigotes are submitted to hyperosmotic stress, and to the cell surface when amastigotes are released to the extracellular medium. Pharmacological block of TcCat activity also resulted in alterations in the trypomastigotes ability to respond to hyperosmotic stress. We also demonstrate the feasibility of purifying and reconstituting a functional ion channel from T. cruzi after recombinant expression in bacteria. The peculiar characteristics of TcCat could be important for the development of specific inhibitors with therapeutic potential against trypanosomes. The use of high-resolution electrophysiological techniques to study ion channels has provided a large amount of information on functional aspects of these important membrane proteins. However, the study of ion channels in unicellular eukaryotes has been limited to detection of ion conductances in large cells, gene identification studies, and pharmacological treatments to investigate the potential presence of different ion channels. In this paper we report the first identification, functional expression, purification, reconstitution, and electrophysiological characterization with single-molecule resolution of a novel cation channel (TcCat) from Trypanosoma cruzi. This is a novel channel that shares little sequence and functional similarities to other potassium channels and its peculiar characteristics could be important for the development of specific inhibitors with therapeutic potential against trypanosomiasis. Surprisingly, the parasites have the unprecedented ability to rapidly change the localization of the channel when they are exposed to different environmental stresses. We demonstrated the feasibility of purifying and reconstituting a functional ion channel from T. cruzi after recombinant expression in bacteria. In addition, we obtained yeast mutants that will provide a useful genetic system for studies of the assembly and composition of the channel.
Collapse
Affiliation(s)
- Veronica Jimenez
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail: (VJ); (RD)
| | - Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail: (VJ); (RD)
| |
Collapse
|
19
|
Kobayashi Y, Fukuda T, Tanaka M, Matsui T. The anti-atherosclerotic di-peptide, Trp-His, inhibits the phosphorylation of voltage-dependent L-type Ca(2+) channels in rat vascular smooth muscle cells. FEBS Open Bio 2012; 2:83-8. [PMID: 23650584 PMCID: PMC3642122 DOI: 10.1016/j.fob.2012.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 04/12/2012] [Indexed: 11/04/2022] Open
Abstract
Trp-His is the only vasoactive di-peptide known to regulate intracellular Ca2+ ([Ca2+]i) and prevent the onset of atherosclerosis in mice. In this study, we showed that Trp-His reduced the [Ca2+]i elevation in phospholipase C-activated vascular smooth muscle cells (VSMCs), while a mixture of the corresponding constituent amino acids did not show significant reduction. Furthermore, Trp-His suppressed calmodulin-dependent kinase II (CaMK II) activity in angiotensin II-stimulated VSMCs, resulting in the inhibition of phosphorylation of voltage-dependent L-type Ca2+ channels (VDCC). Therefore, Trp-His potentially regulates the VDCC phosphorylation cascade through Ca2+-CaM/CaMK II.
Collapse
Key Words
- 2-APB, 2-aminoethoxydiphenyl borate
- AT2R, angiotensin type 2 receptor
- Ang II, angiotensin II
- CaMK II, calmodulin-dependent kinase II
- Calmodulin-dependent kinase II
- Di-peptide
- ER/SR, endoplasmic reticulum/sarcoplasmic reticulum
- IP3R, inositol 1,4,5-trisphosphate receptor
- Intracellular Ca2+
- L-type Ca2+ channel
- PLC, phospholipase C
- Phos-tag
- VDCC, voltage-dependent L-type Ca2+ channels
- VSMCs, vascular smooth muscle cells
Collapse
Affiliation(s)
- Yutaro Kobayashi
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School of Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | | | | | | |
Collapse
|