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Abstract
Kv channel-interacting proteins (KChIPs) belong to the neuronal calcium sensor (NCS) family of Ca2+-binding EF-hand proteins. KChIPs constitute a group of specific auxiliary β-subunits for Kv4 channels, the molecular substrate of transient potassium currents in both neuronal and non-neuronal tissues. Moreover, KChIPs can interact with presenilins to control ER calcium signaling and apoptosis, and with DNA to control gene transcription. Ca2+ binding via their EF-hands, with the consequence of conformational changes, is well documented for KChIPs. Moreover, the Ca2+ dependence of the presenilin/KChIP complex may be related to Alzheimer’s disease and the Ca2+ dependence of the DNA/KChIP complex to pain sensing. However, only in few cases could the Ca2+ binding to KChIPs be directly linked to the control of excitability in nerve and muscle cells known to express Kv4/KChIP channel complexes. This review summarizes current knowledge about the Ca2+ binding properties of KChIPs and the Ca2+ dependencies of macromolecular complexes containing KChIPs, including those with presenilins, DNA and especially Kv4 channels. The respective physiological or pathophysiolgical roles of Ca2+ binding to KChIPs are discussed.
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Affiliation(s)
- Robert Bähring
- a Institut für Zelluläre und Integrative Physiologie, Zentrum für Experimentelle Medizin , Universitätsklinikum Hamburg-Eppendorf , Hamburg , Germany
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2
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Murphy JG, Hoffman DA. A polybasic motif in alternatively spliced KChIP2 isoforms prevents Ca 2+ regulation of Kv4 channels. J Biol Chem 2019; 294:3683-3695. [PMID: 30622142 DOI: 10.1074/jbc.ra118.006549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/04/2019] [Indexed: 11/06/2022] Open
Abstract
The Kv4 family of A-type voltage-gated K+ channels regulates the excitability in hippocampal pyramidal neuron dendrites and are key determinants of dendritic integration, spike timing-dependent plasticity, long-term potentiation, and learning. Kv4.2 channel expression is down-regulated following hippocampal seizures and in epilepsy, suggesting A-type currents as therapeutic targets. In addition to pore-forming Kv4 subunits, modulatory auxiliary subunits called K+ channel-interacting proteins (KChIPs) modulate Kv4 expression and activity and are required to recapitulate native hippocampal A-type currents in heterologous expression systems. KChIP mRNAs contain multiple start sites and alternative exons that generate considerable N-terminal variation and functional diversity in shaping Kv4 currents. As members of the EF-hand domain-containing neuronal Ca2+ sensor protein family, KChIP auxiliary proteins may convey Ca2+ sensitivity upon Kv4 channels; however, to what degree intracellular Ca2+ regulates KChIP-Kv4.2 complexes is unclear. To answer this question, we expressed KChIP2 with Kv4.2 in HEK293T cells, and, with whole-cell patch-clamp electrophysiology, measured an ∼1.5-fold increase in Kv4.2 current density in the presence of elevated intracellular Ca2+ Intriguingly, the Ca2+ regulation of Kv4 current was specific to KChIP2b and KChIP2c splice isoforms that lack a putative polybasic domain that is present in longer KChIP2a1 and KChIP2a isoforms. Site-directed acidification of the basic residues within the polybasic motif of KChIP2a1 rescued Ca2+-mediated regulation of Kv4 current density. These results support divergent Ca2+ regulation of Kv4 channels mediated by alternative splicing of KChIP2 isoforms. They suggest that distinct KChIP-Kv4 interactions may differentially control excitability and function of hippocampal dendrites.
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Affiliation(s)
- Jonathan G Murphy
- From the NIGMS and .,Section on Molecular Neurophysiology, NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Dax A Hoffman
- Section on Molecular Neurophysiology, NICHD, National Institutes of Health, Bethesda, Maryland 20892
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3
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Azam S, Louis GS, Miksovska J. Cadmium association with DREAM promotes DREAM interactions with intracellular partners in a similar manner to its physiological ligand, calcium. Metallomics 2019; 11:1115-1127. [DOI: 10.1039/c9mt00059c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cd2+exposure has been associated with neurodegenerative diseases and other pathologies, but the underlying mechanism through which it exerts toxic effects remain unresolved.
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Affiliation(s)
- Samiol Azam
- Department of Chemistry and Biochemistry, Florida International University
- Miami
- USA
| | - Gessica St Louis
- Department of Chemistry and Biochemistry, Florida International University
- Miami
- USA
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry, Florida International University
- Miami
- USA
- Biomolecular Sciences Institute, Florida International University
- Miami
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4
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Kim HJ, Lee WH, Kim MJ, Shin S, Jang B, Park JB, Wasco W, Buxbaum JD, Kim YS, Choi EK. Calsenilin, a Presenilin Interactor, Regulates RhoA Signaling and Neurite Outgrowth. Int J Mol Sci 2018; 19:ijms19041196. [PMID: 29652865 PMCID: PMC5979497 DOI: 10.3390/ijms19041196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/06/2018] [Accepted: 04/09/2018] [Indexed: 11/24/2022] Open
Abstract
Calsenilin modulates A-type potassium channels, regulates presenilin-mediated γ-secretase activity, and represses prodynorphin and c-fos genes expression. RhoA is involved in various cellular functions including proliferation, differentiation, migration, transcription, and regulation of the actin cytoskeleton. Although recent studies demonstrate that calsenilin can directly interact with RhoA and that RhoA inactivation is essential for neuritogenesis, it is uncertain whether there is a link between calsenilin and RhoA-regulated neuritogenesis. Here, we investigated the role of calsenilin in RhoA-regulated neuritogenesis using in vitro and in vivo systems. We found that calsenilin induced RhoA inactivation, which accompanied RhoA phosphorylation and the reduced phosphorylation levels of LIM kinase (LIMK) and cofilin. Interestingly, PC12 cells overexpressing either full-length (FL) or the caspase 3-derived C-terminal fragment (CTF) of calsenilin significantly inactivated RhoA through its interaction with RhoA and p190 Rho GTPase-activating protein (p190RhoGAP). In addition, cells expressing FL and the CTF of calsenilin had increased neurite outgrowth compared to cells expressing the N-terminal fragment (NTF) of calsenilin or vector alone. Moreover, Tat-C3 and Y27632 treatment significantly increased the percentage of neurite-bearing cells, neurite length, and the number of neurites in cells. Finally, calsenilin deficiency in the brains of calsenilin-knockout mice significantly interfered with RhoA inactivation. These findings suggest that calsenilin contributes to neuritogenesis through RhoA inactivation.
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Affiliation(s)
- Hee-Jun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Korea.
| | - Won-Haeng Lee
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Korea.
- Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon, Gangwon-do 24252, Korea.
| | - Mo-Jong Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Korea.
- Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon, Gangwon-do 24252, Korea.
| | - Sunmee Shin
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Korea.
| | - Byungki Jang
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Korea.
| | - Jae-Bong Park
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon, Gangwon-do 24252, Korea.
| | - Wilma Wasco
- Genetics and Aging Research Unit, Mass General Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
| | - Joseph D Buxbaum
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Yong-Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Korea.
- Department of Microbiology, College of Medicine, Hallym University, Chuncheon, Gangwon-do 24252, Korea.
| | - Eun-Kyoung Choi
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do 14066, Korea.
- Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon, Gangwon-do 24252, Korea.
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Zhang J, Li J, Craig TA, Kumar R, Gross ML. Hydrogen-Deuterium Exchange Mass Spectrometry Reveals Calcium Binding Properties and Allosteric Regulation of Downstream Regulatory Element Antagonist Modulator (DREAM). Biochemistry 2017. [PMID: 28627884 DOI: 10.1021/acs.biochem.7b00100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Downstream regulatory element antagonist modulator (DREAM) is an EF-hand Ca2+-binding protein that also binds to a specific DNA sequence, downstream regulatory elements (DRE), and thereby regulates transcription in a calcium-dependent fashion. DREAM binds to DRE in the absence of Ca2+ but detaches from DRE under Ca2+ stimulation, allowing gene expression. The Ca2+ binding properties of DREAM and the consequences of the binding on protein structure are key to understanding the function of DREAM. Here we describe the application of hydrogen-deuterium exchange mass spectrometry (HDX-MS) and site-directed mutagenesis to investigate the Ca2+ binding properties and the subsequent conformational changes of full-length DREAM. We demonstrate that all EF-hands undergo large conformation changes upon calcium binding even though the EF-1 hand is not capable of binding to Ca2+. Moreover, EF-2 is a lower-affinity site compared to EF-3 and -4 hands. Comparison of HDX profiles between wild-type DREAM and two EF-1 mutated constructs illustrates that the conformational changes in the EF-1 hand are induced by long-range structural interactions. HDX analyses also reveal a conformational change in an N-terminal leucine-charged residue-rich domain (LCD) remote from Ca2+-binding EF-hands. This LCD domain is responsible for the direct interaction between DREAM and cAMP response element-binding protein (CREB) and regulates the recruitment of the co-activator, CREB-binding protein. These long-range interactions strongly suggest how conformational changes transmit the Ca2+ signal to CREB-mediated gene transcription.
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Affiliation(s)
- Jun Zhang
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Jing Li
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Theodore A Craig
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic , Rochester, Minnesota 55905, United States
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic , Rochester, Minnesota 55905, United States
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
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Downstream Regulatory Element Antagonist Modulator (DREAM), a target for anti-thrombotic agents. Pharmacol Res 2017; 117:283-287. [PMID: 28065857 DOI: 10.1016/j.phrs.2017.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/03/2017] [Indexed: 11/21/2022]
Abstract
Circulating platelets participate in the process of numerous diseases including thrombosis, inflammation, and cancer. Thus, it is of great importance to understand the underlying mechanisms mediating platelet activation under disease conditions. Emerging evidence indicates that despite the lack of a nucleus, platelets possess molecules that are involved in gene transcription in nucleated cells. This review will summarize downstream regulatory element antagonist modulator (DREAM), a transcriptional repressor, and highlight recent findings suggesting its novel non-transcriptional role in hemostasis and thrombosis.
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7
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DREAM plays an important role in platelet activation and thrombogenesis. Blood 2016; 129:209-225. [PMID: 27903531 DOI: 10.1182/blood-2016-07-724419] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 11/23/2016] [Indexed: 01/18/2023] Open
Abstract
Downstream regulatory element antagonist modulator (DREAM), a transcriptional repressor, is known to modulate pain responses. However, it is unknown whether DREAM is expressed in anucleate platelets and plays a role in thrombogenesis. By using intravital microscopy with DREAM-null mice and their bone marrow chimeras, we demonstrated that both hematopoietic and nonhematopoietic cell DREAMs are required for platelet thrombus formation following laser-induced arteriolar injury. In a FeCl3-induced thrombosis model, we found that compared with wild-type (WT) control and nonhematopoietic DREAM knockout (KO) mice, DREAM KO control and hematopoietic DREAM KO mice showed a significant delay in time to occlusion. Tail bleeding time was prolonged in DREAM KO control mice, but not in WT or DREAM bone marrow chimeric mice. In vivo adoptive transfer experiments further indicated the importance of platelet DREAM in thrombogenesis. We found that DREAM deletion does not alter the ultrastructural features of platelets but significantly impairs platelet aggregation and adenosine triphosphate secretion induced by numerous agonists (collagen-related peptide, adenosine 5'-diphosphate, A23187, thrombin, or U46619). Biochemical studies revealed that platelet DREAM positively regulates phosphoinositide 3-kinase (PI3K) activity during platelet activation. Using DREAM-null platelets and PI3K isoform-specific inhibitors, we observed that platelet DREAM is important for α-granule secretion, Ca2+ mobilization, and aggregation through PI3K class Iβ (PI3K-Iβ). Genetic and pharmacological studies in human megakaryoblastic MEG-01 cells showed that DREAM is important for A23187-induced Ca2+ mobilization and its regulatory function requires Ca2+ binding and PI3K-Iβ activation. These results suggest that platelet DREAM regulates PI3K-Iβ activity and plays an important role during thrombus formation.
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Pham K, Miksovska J. Molecular insight of DREAM and presenilin 1 C-terminal fragment interactions. FEBS Lett 2016; 590:1114-22. [PMID: 27009418 DOI: 10.1002/1873-3468.12156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 02/24/2016] [Accepted: 03/21/2016] [Indexed: 12/21/2022]
Abstract
Interactions between downstream regulatory element antagonist modulator (DREAM) and presenilin 1 (PS1) are related to numerous neuronal processes. We demonstrate that association of PS1 carboxyl peptide (residues 445-467, HL9) with DREAM is calcium dependent and stabilized by a cluster of three aromatic residues: F462 and F465 from PS1 and F252 from DREAM. Additional stabilization is provided by residues in a loop connecting α helices 7 and 8 in DREAM and residues of PS1, namely cation-π interactions between R200 in DREAM and F465 in PS1 and the salt bridges formed by R207 in DREAM and D450 and D458 in PS1.
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Affiliation(s)
- Khoa Pham
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
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9
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Gonzalez WG, Arango AS, Miksovska J. Amphiphilic Residues 29–44 of DREAM N-Termini Mediate Calmodulin:DREAM Complex Formation. Biochemistry 2015; 54:4391-403. [DOI: 10.1021/acs.biochem.5b00251] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Walter G. Gonzalez
- Department
of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Andres S. Arango
- Department
of Physics, Florida International University, Miami, Florida 33199, United States
| | - Jaroslava Miksovska
- Department
of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
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10
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Pham K, Dhulipala G, Gonzalez WG, Gerstman BS, Regmi C, Chapagain PP, Miksovska J. Ca2+ and Mg2+ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator. Protein Sci 2015; 24:741-51. [PMID: 25627705 DOI: 10.1002/pro.2646] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/25/2015] [Indexed: 11/09/2022]
Abstract
Downstream Regulatory Element Antagonist Modulator (DREAM) belongs to the family of neuronal calcium sensors (NCS) that transduce the intracellular changes in Ca(2+) concentration into a variety of responses including gene expression, regulation of Kv channel activity, and calcium homeostasis. Despite the significant sequence and structural similarities with other NCS members, DREAM shows several features unique among NCS such as formation of a tetramer in the apo-state, and interactions with various intracellular biomacromolecules including DNA, presenilin, Kv channels, and calmodulin. Here we use spectroscopic techniques in combination with molecular dynamics simulation to study conformational changes induced by Ca(2+) /Mg(2+) association to DREAM. Our data indicate a minor impact of Ca(2+) association on the overall structure of the N- and C-terminal domains, although Ca(2+) binding decreases the conformational heterogeneity as evident from the decrease in the fluorescence lifetime distribution in the Ca(2+) bound forms of the protein. Time-resolved fluorescence data indicate that Ca(2+) binding triggers a conformational transition that is characterized by more efficient quenching of Trp residue. The unfolding of DREAM occurs through an partially unfolded intermediate that is stabilized by Ca(2+) association to EF-hand 3 and EF-hand 4. The native state is stabilized with respect to the partially unfolded state only in the presence of both Ca(2+) and Mg(2+) suggesting that, under physiological conditions, Ca(2+) free DREAM exhibits a high conformational flexibility that may facilitate its physiological functions.
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Affiliation(s)
- Khoa Pham
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199
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Protein-Protein Interactions: Gene Acronym Redundancies and Current Limitations Precluding Automated Data Integration. Proteomes 2013; 1:3-24. [PMID: 28250396 PMCID: PMC5314489 DOI: 10.3390/proteomes1010003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/16/2013] [Accepted: 05/21/2013] [Indexed: 12/31/2022] Open
Abstract
Understanding protein interaction networks and their dynamic changes is a major challenge in modern biology. Currently, several experimental and in silico approaches allow the screening of protein interactors in a large-scale manner. Therefore, the bulk of information on protein interactions deposited in databases and peer-reviewed published literature is constantly growing. Multiple databases interfaced from user-friendly web tools recently emerged to facilitate the task of protein interaction data retrieval and data integration. Nevertheless, as we evidence in this report, despite the current efforts towards data integration, the quality of the information on protein interactions retrieved by in silico approaches is frequently incomplete and may even list false interactions. Here we point to some obstacles precluding confident data integration, with special emphasis on protein interactions, which include gene acronym redundancies and protein synonyms. Three human proteins (choline kinase, PPIase and uromodulin) and three different web-based data search engines focused on protein interaction data retrieval (PSICQUIC, DASMI and BIPS) were used to explain the potential occurrence of undesired errors that should be considered by researchers in the field. We demonstrate that, despite the recent initiatives towards data standardization, manual curation of protein interaction networks based on literature searches are still required to remove potential false positives. A three-step workflow consisting of: (i) data retrieval from multiple databases, (ii) peer-reviewed literature searches, and (iii) data curation and integration, is proposed as the best strategy to gather updated information on protein interactions. Finally, this strategy was applied to compile bona fide information on human DREAM protein interactome, which constitutes liable training datasets that can be used to improve computational predictions.
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Craig TA, Ramachandran PL, Bergen HR, Podratz JL, Windebank AJ, Kumar R. The regulation of apoptosis by the downstream regulatory element antagonist modulator/potassium channel interacting protein 3 (DREAM/KChIP3) through interactions with hexokinase I. Biochem Biophys Res Commun 2013; 433:508-12. [PMID: 23524266 DOI: 10.1016/j.bbrc.2013.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 03/06/2013] [Indexed: 12/25/2022]
Abstract
The EF-hand protein, DREAM/KChIP3 (henceforth referred to as DREAM), regulates apoptosis by incompletely understood mechanisms. We demonstrate that in the presence of Ca2+, DREAM interacts with hexokinase I, a protein known to bind mitochondria and regulate apoptosis. A mutant DREAM protein construct incapable of binding Ca2+ does not associate with hexokinase I. The amino-terminal portion of DREAM is required for binding to hexokinase I, as a DREAM construct lacking the first 94 amino terminal residues fails to bind hexokinase I. Expression of DREAM in neuroblastoma cells enhances cisplatin mediated caspase-3 activity. Simultaneous expression of hexokinase I in such cells reduces DREAM-stimulated apoptosis. DREAM overexpression in neuroblastoma cells reduces hexokinase I localization on isolated mitochondria. The interaction of DREAM with hexokinase I may be important in the regulation of neuronal apoptosis.
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Affiliation(s)
- Theodore A Craig
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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