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Soubise B, Jiang Y, Douet-Guilbert N, Troadec MB. RBM22, a Key Player of Pre-mRNA Splicing and Gene Expression Regulation, Is Altered in Cancer. Cancers (Basel) 2022; 14:cancers14030643. [PMID: 35158909 PMCID: PMC8833553 DOI: 10.3390/cancers14030643] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/19/2022] [Accepted: 01/22/2022] [Indexed: 01/05/2023] Open
Abstract
RNA-Binding Proteins (RBP) are very diverse and cover a large number of functions in the cells. This review focuses on RBM22, a gene encoding an RBP and belonging to the RNA-Binding Motif (RBM) family of genes. RBM22 presents a Zinc Finger like and a Zinc Finger domain, an RNA-Recognition Motif (RRM), and a Proline-Rich domain with a general structure suggesting a fusion of two yeast genes during evolution: Cwc2 and Ecm2. RBM22 is mainly involved in pre-mRNA splicing, playing the essential role of maintaining the conformation of the catalytic core of the spliceosome and acting as a bridge between the catalytic core and other essential protein components of the spliceosome. RBM22 is also involved in gene regulation, and is able to bind DNA, acting as a bona fide transcription factor on a large number of target genes. Undoubtedly due to its wide scope in the regulation of gene expression, RBM22 has been associated with several pathologies and, notably, with the aggressiveness of cancer cells and with the phenotype of a myelodysplastic syndrome. Mutations, enforced expression level, and haploinsufficiency of RBM22 gene are observed in those diseases. RBM22 could represent a potential therapeutic target in specific diseases, and, notably, in cancer.
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Affiliation(s)
- Benoît Soubise
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (B.S.); (Y.J.); (N.D.-G.)
| | - Yan Jiang
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (B.S.); (Y.J.); (N.D.-G.)
- Department of Hematology, The First Hospital of Jilin University, Changchun 130021, China
| | - Nathalie Douet-Guilbert
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (B.S.); (Y.J.); (N.D.-G.)
- CHRU Brest, Service de Génétique, Laboratoire de Génétique Chromosomique, F-29200 Brest, France
| | - Marie-Bérengère Troadec
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (B.S.); (Y.J.); (N.D.-G.)
- CHRU Brest, Service de Génétique, Laboratoire de Génétique Chromosomique, F-29200 Brest, France
- Correspondence: ; Tel.: +33-2-98-01-64-55
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2
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Structure, Function and Regulation of the Plasma Membrane Calcium Pump in Health and Disease. Int J Mol Sci 2022; 23:ijms23031027. [PMID: 35162948 PMCID: PMC8835232 DOI: 10.3390/ijms23031027] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/30/2021] [Accepted: 01/06/2022] [Indexed: 12/28/2022] Open
Abstract
In this review, I summarize the present knowledge of the structural and functional properties of the mammalian plasma membrane calcium pump (PMCA). It is outlined how the cellular expression of the different spliced isoforms of the four genes are regulated under normal and pathological conditions.
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3
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Liu J, Li Y, Gao N, Ji J, He Q. Calcium/calmodulin-dependent protein kinase IV regulates vascular autophagy and insulin signaling through Akt/mTOR/CREB pathway in ob/ob mice. J Physiol Biochem 2021; 78:199-211. [PMID: 34741274 DOI: 10.1007/s13105-021-00853-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 10/20/2021] [Indexed: 10/19/2022]
Abstract
Calcium/calmodulin-dependent protein kinase IV (CaMKIV) has recently emerged as an important regulator of glucose metabolism and vascular function, but the underlying mechanism is not fully understood. Recently, we revealed that CaMKIV limits metabolic disorder and liver insulin resistance and regulates autophagy in high-fat diet-induced obese mice. In the present study, we demonstrated that CaMKIV was not only associated with improvement of glucose tolerance and insulin sensitivity in ob/ob mice but also involved in the regulation of vascular autophagy and mitochondrial biogenesis. Our in vitro data indicated that CaMKIV reversed autophagic imbalance and restored insulin sensitivity in palmitate-induced A7r5 cells with insulin resistance. However, the protective effects of CaMKIV were nullified by suppression of Akt, mTOR, or CREB, suggesting that CaMKIV inhibits autophagy and improves insulin signaling in insulin resistance cell models in an Akt/mTOR/CREB-dependent manner. CaMKIV reversed autophagic imbalance and insulin sensitivity in vascular tissues and vascular cells through Akt/mTOR/CREB signaling, which could be regarded as a novel opportunity for the treatment of insulin resistance.
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Affiliation(s)
- Jiali Liu
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China
| | - Yue Li
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China
| | - Ning Gao
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China
| | - Jing Ji
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China
| | - Qian He
- Department of Clinical Laboratory, Xi'an Jiaotong University Second Affiliated Hospital, 157 West 5 Road, Xi'an, 710004, Shaanxi, China.
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4
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Quantitative Proteomics and Phosphoproteomics Reveal TNF-α-Mediated Protein Functions in Hepatocytes. Molecules 2021; 26:molecules26185472. [PMID: 34576943 PMCID: PMC8464716 DOI: 10.3390/molecules26185472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 11/18/2022] Open
Abstract
Increased secretion of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNFα), is often associated with adipose tissue dysregulation, which often accompanies obesity. High levels of TNFα have been linked to the development of insulin resistance in several tissues and organs, including skeletal muscle and the liver. In this study, we examined the complex regulatory roles of TNFα in murine hepatocytes utilizing a combination of global proteomic and phosphoproteomic analyses. Our results show that TNFα promotes extensive changes not only of protein levels, but also the dynamics of their downstream phosphorylation signaling. We provide evidence that TNFα induces DNA replication and promotes G1/S transition through activation of the MAPK pathway. Our data also highlight several other novel proteins, many of which are regulated by phosphorylation and play a role in the progression and development of insulin resistance in hepatocytes.
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5
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The Calcium/Calmodulin-Dependent Kinases II and IV as Therapeutic Targets in Neurodegenerative and Neuropsychiatric Disorders. Int J Mol Sci 2021; 22:ijms22094307. [PMID: 33919163 PMCID: PMC8122486 DOI: 10.3390/ijms22094307] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/13/2021] [Accepted: 04/17/2021] [Indexed: 12/14/2022] Open
Abstract
CaMKII and CaMKIV are calcium/calmodulin-dependent kinases playing a rudimentary role in many regulatory processes in the organism. These kinases attract increasing interest due to their involvement primarily in memory and plasticity and various cellular functions. Although CaMKII and CaMKIV are mostly recognized as the important cogs in a memory machine, little is known about their effect on mood and role in neuropsychiatric diseases etiology. Here, we aimed to review the structure and functions of CaMKII and CaMKIV, as well as how these kinases modulate the animals’ behavior to promote antidepressant-like, anxiolytic-like, and procognitive effects. The review will help in the understanding of the roles of the above kinases in the selected neurodegenerative and neuropsychiatric disorders, and this knowledge can be used in future drug design.
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6
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Chen MF. The role of calmodulin and calmodulin-dependent protein kinases in the pathogenesis of atherosclerosis. Tzu Chi Med J 2021; 34:160-168. [PMID: 35465283 PMCID: PMC9020235 DOI: 10.4103/tcmj.tcmj_119_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 05/31/2021] [Accepted: 06/29/2021] [Indexed: 12/02/2022] Open
Abstract
Atherosclerosis is a chronic inflammatory disease that triggers severe thrombotic cardiovascular events, such as stroke and myocardial infarction. In atherosclerotic processes, both macrophages and vascular smooth muscle cells (VSMCs) are essential cell components in atheromata formation through proinflammatory cytokine secretion, defective efferocytosis, cell migration, and proliferation, primarily controlled by Ca2+-dependent signaling. Calmodulin (CaM), as a versatile Ca2+ sensor in diverse cell types, regulates a broad spectrum of Ca2+-dependent cell functions through the actions of downstream protein kinases. Thus, this review focuses on discussing how CaM and CaM-dependent kinases (CaMKs) regulate the functions of macrophages and VSMCs in atherosclerotic plaque development based on literature from open databases. A central theme in this review is a summary of the mechanisms and consequences underlying CaMK-mediated macrophage inflammation and apoptosis, which are the key processes in necrotic core formation in atherosclerosis. Another central theme is addressing the role of CaM and CaMK-dependent pathways in phenotypic modulation, migration, and proliferation of VSMCs in atherosclerotic progression. A complete understanding of CaM and CaMK-controlled individual processes involving macrophages and VSMCs in atherogenesis might provide helpful information for developing potential therapeutic targets and strategies.
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Williams RJ, Karpuzoglu E, Connell H, Hurley DJ, Holladay SD, Gogal RM. Lead alters intracellular protein signaling and suppresses pro-inflammatory activation in TLR4 and IFNR-stimulated murine RAW 264.7 cells, in vitro. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2019; 82:279-298. [PMID: 30890031 DOI: 10.1080/15287394.2019.1591315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Lead (Pb) is a persistent environmental pollutant that has a structure and charge similar to many ions, such as calcium, that are essential for normal cellular function. Pb may compete with calcium for protein binding sites and inhibit signaling pathways within the cell affecting many organ systems including the immune system. The aim of the current study was to assess whether the calcium/calmodulin pathway is a principal target of environmentally relevant Pb during pro-inflammatory activation in a RAW 264.7 macrophage cell line. RAW 264.7 cells were cultured with 5 μM Pb(NO3)2, LPS, rIFNγ, or LPS+rIFNγ for 12, 24, or 48 hr. Intracellular protein signaling and multiple functional endpoints were investigated to determine Pb-mediated effects on macrophage function. Western blot analysis revealed that Pb initially modulated nuclear localization of NFκB p65 and cytoplasmic phosphorylation of CaMKIV accompanied by increased phosphorylation of STAT1β at 24 hr. Macrophage proliferation was significantly decreased at 12 hr in the presence of Pb, while nitric oxide (NO) was significantly reduced at 12 and 24 hr. Cells cultured with Pb for 12, 24, or 48 hr exhibited altered cytokine levels after specific stimuli activation. Our findings are in agreement with previous reports suggesting that macrophage pro-inflammatory responses are significantly modulated by Pb. Further, Pb-induced phosphorylation of CaMKIV (pCaMKIV), observed in the present study, may be a contributing factor in metal-induced autophagy noted in our previous study with this same cell line.
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Affiliation(s)
- R J Williams
- a Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine , University of Georgia , Athens , GA , USA
| | - E Karpuzoglu
- a Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine , University of Georgia , Athens , GA , USA
| | - H Connell
- b Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, Pharmacy South , University of Georgia , Athens , GA , USA
| | - D J Hurley
- c Department of Population Health, College of Veterinary Medicine , University of Georgia , Athens , GA , USA
| | - S D Holladay
- a Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine , University of Georgia , Athens , GA , USA
| | - R M Gogal
- a Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine , University of Georgia , Athens , GA , USA
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The Plasma Membrane Calcium Pump (PMCA): Regulation of Cytosolic Ca2+, Genetic Diversities and Its Role in Sub-plasma Membrane Microdomains. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:3-21. [DOI: 10.1007/978-3-319-55858-5_1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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9
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Implications of the thyroid hormone on neuronal development with special emphasis on the calmodulin-kinase IV pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:877-882. [PMID: 27939430 DOI: 10.1016/j.bbamcr.2016.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/29/2016] [Accepted: 12/02/2016] [Indexed: 12/16/2022]
Abstract
Thyroid hormones influence brain development through regulation of gene expression. This is especially true for Ca2+-dependent regulation since a major pathway is controlled by the Ca2+/calmodulin-dependent protein kinase IV (CaMKIV) which in turn is induced by the thyroid hormone T3. In addition, CaMKIV is involved in regulation of alternative splicing of a number of protein isoforms, among them PMCA1a, the neuronal specific isoform of the plasma membrane calcium pump. On the other hand, hypothyroidism or CaMKIV deficiency can have a severe influence on brain development. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Jameel E, Naz H, Khan P, Tarique M, Kumar J, Mumtazuddin S, Ahamad S, Islam A, Ahmad F, Hoda N, Hassan MI. Design, synthesis, and biological evaluation of pyrimidine derivatives as potential inhibitors of human calcium/calmodulin-dependent protein kinase IV. Chem Biol Drug Des 2016; 89:741-754. [PMID: 27809417 DOI: 10.1111/cbdd.12898] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/17/2016] [Accepted: 10/22/2016] [Indexed: 01/18/2023]
Abstract
Calcium/calmodulin-dependent protein kinase IV (CAMKIV) is a multifunctional Ser/Thr kinase, associated with cerebral hypoxia, cancer, and neurodegenerative diseases. Here, we report design, synthesis, and biological evaluation of seven pyrimidine-substituted novel inhibitors of CAMKIV. We successfully synthesized and extensively characterized (ESI-MS, 1 H NMR, and 13 C NMR studies) seven compounds that are showing appreciable binding affinity to the CAMKIV. Molecular docking and fluorescence binding studies revealed that compound 1 is showing very high binding free energy (ΔG = -11.52 kcal/mol) and binding affinity (K = 9.2 × 1010 m-1 ) to the CAMKIV. We further performed MTT assay to check the cytotoxicity and anticancer activity of these compounds. An appreciable IC50 (39 μm) value of compound 1 was observed on human hepatoma cell line and nontoxic till the 400 μm on human embryonic kidney cells. To ensure anticancer activity of all these compounds, we further performed propidium iodide assay to evaluate cell viability and DNA content during the cell cycle. We found that compound 1 is again showing a better anticancer activity on both human hepatoma and human embryonic kidney cell lines.
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Affiliation(s)
- Ehtesham Jameel
- Department of Chemistry, B.R. Ambedkar Bihar University, Muzaffarpur, Bihar, India
| | - Huma Naz
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Parvez Khan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Mohd Tarique
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
| | - Jitendra Kumar
- Department of Chemistry, Jamia Millia Islamia, New Delhi, India
| | - Syed Mumtazuddin
- Department of Chemistry, B.R. Ambedkar Bihar University, Muzaffarpur, Bihar, India
| | - Shahzaib Ahamad
- Department of Biotechnology, College of Engineering and Technology, IFTM, Moradabad, India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Nasimul Hoda
- Department of Chemistry, Jamia Millia Islamia, New Delhi, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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Wang MT, Holderfield M, Galeas J, Delrosario R, To MD, Balmain A, McCormick F. K-Ras Promotes Tumorigenicity through Suppression of Non-canonical Wnt Signaling. Cell 2016; 163:1237-1251. [PMID: 26590425 DOI: 10.1016/j.cell.2015.10.041] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/01/2015] [Accepted: 10/13/2015] [Indexed: 12/30/2022]
Abstract
K-Ras and H-Ras share identical effectors and have similar properties; however, the high degree of tumor-type specificity associated with K-Ras and H-Ras mutations suggests that they have unique roles in oncogenesis. Here, we report that oncogenic K-Ras, but not H-Ras, suppresses non-canonical Wnt/Ca(2+) signaling, an effect that contributes strongly to its tumorigenic properties. K-Ras does this by binding to calmodulin and so reducing CaMKii activity and expression of Fzd8. Restoring Fzd8 in K-Ras mutant pancreatic cells suppresses malignancy, whereas depletion of Fzd8 in H-Ras(V12)-transformed cells enhances their tumor initiating capacity. Interrupting K-Ras-calmodulin binding using genetic means or by treatment with an orally active protein kinase C (PKC)-activator, prostratin, represses tumorigenesis in K-Ras mutant pancreatic cancer cells. These findings provide an alternative way to selectively target this "undruggable" protein.
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Affiliation(s)
- Man-Tzu Wang
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Matthew Holderfield
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Jacqueline Galeas
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Reyno Delrosario
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Minh D To
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Allan Balmain
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Frank McCormick
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA.
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Naz H, Shahbaaz M, Bisetty K, Islam A, Ahmad F, Hassan MI. Effect of pH on the structure, function, and stability of human calcium/calmodulin-dependent protein kinase IV: combined spectroscopic and MD simulation studies. Biochem Cell Biol 2016; 94:221-8. [PMID: 27032767 DOI: 10.1139/bcb-2015-0132] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human calcium/calmodulin-dependent protein kinase IV (CAMKIV) is a member of Ser/Thr protein kinase family. It is regulated by the calcium-calmodulin dependent signal through a secondary messenger, Ca(2+), which leads to the activation of its autoinhibited form. The over-expression and mutation in CAMKIV as well as change in Ca(2+) concentration is often associated with numerous neurodegenerative diseases and cancers. We have successfully cloned, expressed, and purified a functionally active kinase domain of human CAMKIV. To observe the effect of different pH conditions on the structural and functional properties of CAMKIV, we have used spectroscopic techniques such as circular diachroism (CD) absorbance and fluorescence. We have observed that within the pH range 5.0-11.5, CAMKIV maintained both its secondary and tertiary structures, along with its function, whereas significant aggregation was observed at acidic pH (2.0-4.5). We have also performed ATPase activity assays under different pH conditions and found a significant correlation between the structure and enzymatic activities of CAMKIV. In-silico validations were further carried out by modeling the 3-dimensional structure of CAMKIV and then subjecting it to molecular dynamics (MD) simulations to understand its conformational behavior in explicit water conditions. A strong correlation between spectroscopic observations and the output of molecular dynamics simulation was observed for CAMKIV.
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Affiliation(s)
- Huma Naz
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Mohd Shahbaaz
- b Department of Chemistry, Durban University of Technology, Durban-4000, South Africa
| | - Krishna Bisetty
- b Department of Chemistry, Durban University of Technology, Durban-4000, South Africa
| | - Asimul Islam
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Faizan Ahmad
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Md Imtaiyaz Hassan
- a Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
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Calcium/calmodulin-dependent protein kinase IV: A multifunctional enzyme and potential therapeutic target. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:54-65. [PMID: 26773169 DOI: 10.1016/j.pbiomolbio.2015.12.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 12/21/2015] [Accepted: 12/28/2015] [Indexed: 01/23/2023]
Abstract
The calcium/calmodulin-dependent protein kinase IV (CAMKIV) belongs to the serine/threonine protein kinase family, and is primarily involved in transcriptional regulation in lymphocytes, neurons and male germ cells. CAMKIV operates the signaling cascade and regulates activity of several transcription activators by phosphorylation, which in turn plays pivotal roles in immune response, inflammation and memory consolidation. In this review, we tried to focus on different aspects of CAMKIV to understand the significance of this protein in the biological system. This enzyme is associated with varieties of disorders such as cerebral hypoxia, azoospermia, endometrial and ovarian cancer, systemic lupus, etc., and hence it is considered as a potential therapeutic target. Structure of CAMKIV is comprised of five distinct domains in which kinase domain is responsible for enzyme activity. CAMKIV is involved in varieties of cellular functions such as regulation of gene expression, T-cell maturation, regulation of survival phase of dendritic cells, bone growth and metabolism, memory consolidation, sperm motility, regulation of microtubule dynamics, cell-cycle progression and apoptosis. In this review, we performed an extensive analysis on structure, function and regulation of CAMKIV and associated diseases.
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Naz H, Jameel E, Hoda N, Shandilya A, Khan P, Islam A, Ahmad F, Jayaram B, Hassan MI. Structure guided design of potential inhibitors of human calcium-calmodulin dependent protein kinase IV containing pyrimidine scaffold. Bioorg Med Chem Lett 2015; 26:782-788. [PMID: 26783179 DOI: 10.1016/j.bmcl.2015.12.098] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 12/01/2015] [Accepted: 12/29/2015] [Indexed: 12/26/2022]
Abstract
Calmodulin dependent protein kinase IV (CAMKIV) belongs to the serine/threonine protein kinase family and considered as an encouraging target for the development of novel anticancer agents. The interaction and binding behavior of three designed inhibitors of human CAMKIV, containing pyrimidine scaffold, was monitored by in vitro fluorescence titration and molecular docking calculations under physiological condition. In silico docking studies were performed to screen several compounds containing pyrimidine scaffold against CAMKIV. Molecular docking calculation predicted the binding of these ligands in active-site cavity of the CAMKIV structure correlating such interactions with a probable inhibition mechanism. Finally, three active pyrimidine substituted compounds (molecules 1-3) have been successfully synthesized and characterized by (1)H and (13)C NMR. Molecule 3 is showing very high binding-affinity for the CAMKIV, with a binding constant of 2.2×10(8), M(-1) (±0.20). All three compounds are nontoxic to HEK293 cells up to 50 μM. The cell proliferation inhibition study showed that the molecule 3 has lowest IC50 value (46±1.08 μM). The theoretical and experimental observations are significantly correlated. This study reveals some important observations to generate an improved pyrimidine based compound that holds promise as a therapeutic agent for the treatment of cancer and neurodegenerative diseases.
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Affiliation(s)
- Huma Naz
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Ehtesham Jameel
- Department of Chemistry, B.R. Ambedkar Bihar University, Muzaffarpur 842001, Bihar, India
| | - Nasimul Hoda
- Department of Chemistry, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
| | - Ashutosh Shandilya
- Supercomputing Facility for Bioinformatics & Computational Biology, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India; Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Parvez Khan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - B Jayaram
- Supercomputing Facility for Bioinformatics & Computational Biology, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India; Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
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Hoda N, Naz H, Jameel E, Shandilya A, Dey S, Hassan MI, Ahmad F, Jayaram B. Curcumin specifically binds to the human calcium-calmodulin-dependent protein kinase IV: fluorescence and molecular dynamics simulation studies. J Biomol Struct Dyn 2015; 34:572-84. [PMID: 25929263 DOI: 10.1080/07391102.2015.1046934] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Calcium-calmodulin-dependent protein kinase IV (CAMK4) plays significant role in the regulation of calcium-dependent gene expression, and thus, it is involved in varieties of cellular functions such as cell signaling and neuronal survival. On the other hand, curcumin, a naturally occurring yellow bioactive component of turmeric possesses wide spectrum of biological actions, and it is widely used to treat atherosclerosis, diabetes, cancer, and inflammation. It also acts as an antioxidant. Here, we studied the interaction of curcumin with human CAMK4 at pH 7.4 using molecular docking, molecular dynamics (MD) simulations, fluorescence binding, and surface plasmon resonance (SPR) methods. We performed MD simulations for both neutral and anionic forms of CAMK4-curcumin complexes for a reasonably long time (150 ns) to see the overall stability of the protein-ligand complex. Molecular docking studies revealed that the curcumin binds in the large hydrophobic cavity of kinase domain of CAMK4 through several hydrophobic and hydrogen-bonded interactions. Additionally, MD simulations studies contributed in understanding the stability of protein-ligand complex system in aqueous solution and conformational changes in the CAMK4 upon binding of curcumin. A significant increase in the fluorescence intensity at 495 nm was observed (λexc = 425 nm), suggesting a strong interaction of curcumin to the CAMK4. A high binding affinity (KD = 3.7 × 10(-8) ± .03 M) of curcumin for the CAMK4 was measured by SPR further indicating curcumin as a potential ligand for the CAMK4. This study will provide insights into designing a new inspired curcumin derivatives as therapeutic agents against many life-threatening diseases.
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Affiliation(s)
- Nasimul Hoda
- a Department of Chemistry , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Huma Naz
- b Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Ehtesham Jameel
- c Department of Chemistry , Babasaheb Bhimrao Ambedkar Bihar University , Muzaffarpur , Bihar 842002 , India
| | - Ashutosh Shandilya
- d Supercomputing Facility for Bioinformatics & Computational Biology , Indian Institute of Technology , Hauz Khas, New Delhi 110016 , India.,e Department of Chemistry , Indian Institute of Technology , Hauz Khas, New Delhi 110016 , India
| | - Sharmistha Dey
- f Department of Biophysics , All India Institute of Medical Sciences , New Delhi 110029 , India
| | - Md Imtaiyaz Hassan
- b Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - Faizan Ahmad
- b Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India
| | - B Jayaram
- d Supercomputing Facility for Bioinformatics & Computational Biology , Indian Institute of Technology , Hauz Khas, New Delhi 110016 , India.,e Department of Chemistry , Indian Institute of Technology , Hauz Khas, New Delhi 110016 , India
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16
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Krebs J. The plethora of PMCA isoforms: Alternative splicing and differential expression. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:2018-24. [PMID: 25535949 DOI: 10.1016/j.bbamcr.2014.12.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 12/08/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
Abstract
In this review the four different genes of the mammalian plasma membrane calcium ATPase (PMCA) and their spliced isoforms are discussed with respect to their tissue distribution, their differences during development and their importance for regulating Ca²⁺ homeostasis under different conditions. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
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Affiliation(s)
- Joachim Krebs
- NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
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17
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Liu B, Barbosa-Sampaio H, Jones PM, Persaud SJ, Muller DS. The CaMK4/CREB/IRS-2 cascade stimulates proliferation and inhibits apoptosis of β-cells. PLoS One 2012; 7:e45711. [PMID: 23049845 PMCID: PMC3458088 DOI: 10.1371/journal.pone.0045711] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 08/23/2012] [Indexed: 01/09/2023] Open
Abstract
Progressive reduction in β-cell mass is responsible for the development of type 2 diabetes mellitus, and alteration in insulin receptor substrate 2 (IRS-2) abundance plays a critical role in this process. IRS-2 expression is stimulated by the transcription factor cAMP response element-binding protein (CREB) and we recently demonstrated that Ca2+/calmodulin dependent kinase 4 (CaMK4) is upstream of CREB activation in β-cells. This study investigated whether CaMK4 is also a potential target to increase β-cell mass through CREB-mediated IRS-2 expression, by quantifying mouse MIN6 β-cell proliferation and apoptosis following IRS-2 knockdown, CaMKs inhibition and alterations in CaMK4 and CREB expression. Expression of constitutively active CaMK4 (ΔCaMK4) and CREB (CREBDIEDLM) significantly stimulated β-cell proliferation and survival. In contrast, expression of their corresponding dominant negative forms (ΔK75ECaMK4 and CREBM1) and silencing of IRS-2 increased apoptosis and reduced β-cell division. Moreover, CREBDIEDLM and CREBM1 expression completely abolished the effects of ΔK75ECaMK4 and of ΔCaMK4, respectively. Our results indicate that CaMK4 regulates β-cell proliferation and apoptosis in a CREB-dependent manner and that CaMK4-induced IRS-2 expression is important in these processes.
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Affiliation(s)
- Bo Liu
- Diabetes Research Group, School of Medicine, Division of Diabetes & Nutritional Sciences, King’s College London, London, United Kingdom
| | - Helena Barbosa-Sampaio
- Diabetes Research Group, School of Medicine, Division of Diabetes & Nutritional Sciences, King’s College London, London, United Kingdom
| | - Peter M. Jones
- Diabetes Research Group, School of Medicine, Division of Diabetes & Nutritional Sciences, King’s College London, London, United Kingdom
| | - Shanta J. Persaud
- Diabetes Research Group, School of Medicine, Division of Diabetes & Nutritional Sciences, King’s College London, London, United Kingdom
- * E-mail:
| | - Dany S. Muller
- Diabetes Research Group, School of Medicine, Division of Diabetes & Nutritional Sciences, King’s College London, London, United Kingdom
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18
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Ca2+-signaling, alternative splicing and endoplasmic reticulum stress responses. Neurochem Res 2011; 36:1198-211. [PMID: 21365449 DOI: 10.1007/s11064-011-0431-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2011] [Indexed: 01/01/2023]
Abstract
Ca(2+)-signaling, alternative splicing, and stress responses by the endoplasmic reticulum are three important cellular activities which can be strongly interconnected to alter the expression of protein isoforms in a tissue dependent manner or during development depending on the environmental conditions. This integrated network of signaling pathways permits a high degree of versatility and adaptation to metabolic, developmental and stress processes. Defects in its regulation may lead to cellular malfunction.
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19
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Reece KM, Mazalouskas MD, Wadzinski BE. The Balpha and Bdelta regulatory subunits of PP2A are necessary for assembly of the CaMKIV.PP2A signaling complex. Biochem Biophys Res Commun 2009; 386:582-7. [PMID: 19538941 DOI: 10.1016/j.bbrc.2009.06.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 06/10/2009] [Indexed: 11/16/2022]
Abstract
Calcium/calmodulin-dependent protein kinase IV (CaMKIV) is a serine/threonine kinase that is important in synaptic plasticity and T cell maturation. Activation of CaMKIV requires calcium/calmodulin binding and phosphorylation at T200 by CaMK kinase. Our previous work has shown that protein serine/threonine phosphatase 2A (PP2A) forms a complex with CaMKIV and negatively regulates its activity. Here we demonstrate that PP2A tightly regulates T200 phosphorylation of endogenous CaMKIV, but has little effect on the phosphorylation of the ectopically-expressed kinase. This differential regulation of endogenous versus exogenous CaMKIV is due to differences in their ability to associate with PP2A, as exogenous CaMKIV associates poorly with PP2A in comparison to endogenous CaMKIV. The inability of exogenous CaMKIV to associate with PP2A appears to be due to limiting amounts of endogenous PP2A regulatory B subunits, since coexpression of Balpha or Bdelta causes the recruitment of PP2Ac to ectopic CaMKIV, leading to formation of a CaMKIV.PP2A complex. Together, these data indicate that the B subunits are essential for the interaction of PP2A with CaMKIV.
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Affiliation(s)
- Kelie M Reece
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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20
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The influence of calcium signaling on the regulation of alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:979-84. [PMID: 19133299 DOI: 10.1016/j.bbamcr.2008.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 11/27/2008] [Accepted: 12/03/2008] [Indexed: 02/07/2023]
Abstract
In this review the influence of calcium signaling on the regulation of alternative splicing is discussed with respect to its influence on cell- and developmental-specific expression of different isoforms of the plasma membrane calcium pump (PMCA). In a second part the possibility is discussed that due to the interaction of the calcium-binding protein ALG-2 with a spliceosomal regulator of alternative splicing, RBM22, Ca2+-signaling may thus influence its regulatory property.
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21
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Chronic fluoxetine treatment induces brain region-specific upregulation of genes associated with BDNF-induced long-term potentiation. Neural Plast 2008; 2007:26496. [PMID: 18301726 PMCID: PMC2248427 DOI: 10.1155/2007/26496] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Accepted: 07/27/2007] [Indexed: 12/15/2022] Open
Abstract
Several lines of evidence implicate BDNF in the pathogenesis of stress-induced depression and the delayed efficacy of antidepressant drugs. Antidepressant-induced upregulation of BDNF signaling is thought to promote adaptive neuronal plasticity through effects on gene expression, but the effector genes downstream of BDNF has not been identified. Local infusion of BDNF into the dentate gyrus induces a long-term potentiation (BDNF-LTP) of synaptic transmission that requires upregulation of the immediate early gene Arc. Recently, we identified five genes (neuritin, Narp, TIEG1, Carp, and Arl4d) that are coupregulated with Arc during BDNF-LTP. Here, we examined the expression of these genes in the dentate gyrus, hippocampus proper, and prefrontal cortex after antidepressant treatment. We show that chronic, but not acute, fluoxetine administration leads to upregulation of these BDNF-LTP-associated genes in a brain region-specific pattern. These findings link chronic effects of antidepressant treatment to molecular mechanisms underlying BDNF-induced synaptic plasticity.
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22
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Chow FA, Anderson KA, Noeldner PK, Means AR. The autonomous activity of calcium/calmodulin-dependent protein kinase IV is required for its role in transcription. J Biol Chem 2005; 280:20530-8. [PMID: 15769749 DOI: 10.1074/jbc.m500067200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calcium/calmodulin-dependent kinase IV (CaMKIV) is a multifunctional serine/threonine kinase that is positively regulated by two main events. The first is the binding of calcium/calmodulin (Ca(2+)/CaM), which relieves intramolecular autoinhibition of the enzyme and leads to basal kinase activity. The second is activation by the upstream kinase, Ca(2+)/calmodulin-dependent kinase kinase. Phosphorylation of Ca(2+)/CaM-bound CaMKIV on its activation loop threonine (residue Thr(200) in human CaMKIV) by Ca(2+)/calmodulin-dependent kinase kinase leads to increased CaMKIV kinase activity. It has also been repeatedly noted that activation of CaMKIV is accompanied by the generation of Ca(2+)/CaM-independent or autonomous activity, although the significance of this event has been unclear. Here we demonstrate the importance of autonomous activity to CaMKIV biological function. We show that phosphorylation of CaMKIV on Thr(200) leads to the generation of a fully Ca(2+)/CaM-independent enzyme. By analyzing the behavior of wild-type and mutant CaMKIV proteins in biochemical experiments and cellular transcriptional assays, we demonstrate that CaMKIV autonomous activity is necessary and sufficient for CaMKIV-mediated transcription. The ability of wild-type CaMKIV to drive cAMP response element-binding protein-mediated transcription is strictly dependent upon an initiating Ca(2+) stimulus, which leads to kinase activation and development of autonomous activity in cells. Mutant CaMKIV proteins that are incapable of developing autonomous activity within a cellular context fail to drive transcription, whereas certain CaMKIV mutants that possess constitutive autonomous activity drive transcription in the absence of a Ca(2+) stimulus and independent of Ca(2+)/CaM binding or Thr(200) phosphorylation.
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Affiliation(s)
- Felice A Chow
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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23
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Kotera I, Sekimoto T, Miyamoto Y, Saiwaki T, Nagoshi E, Sakagami H, Kondo H, Yoneda Y. Importin alpha transports CaMKIV to the nucleus without utilizing importin beta. EMBO J 2005; 24:942-51. [PMID: 15719015 PMCID: PMC554133 DOI: 10.1038/sj.emboj.7600587] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Accepted: 01/27/2005] [Indexed: 12/20/2022] Open
Abstract
Ca(2+)/calmodulin-dependent protein kinase type IV (CaMKIV) plays an essential role in the transcriptional activation of cAMP response element-binding protein-mediated signaling pathways. Although CaMKIV is localized predominantly in the nucleus, the molecular mechanism of the nuclear import of CaMKIV has not been elucidated. We report here that importin alpha is able to carry CaMKIV into the nucleus without the need for importin beta or any other soluble proteins in digitonin-permeabilized cells. An importin beta binding-deficient mutant (DeltaIBB) of importin alpha also carried CaMKIV into the nucleus, which strongly suggests that CaMKIV is transported in an importin beta-independent manner. While CaMKIV directly interacted with the C-terminal region of importin alpha, the CaMKIV/importin alpha complex did not form a ternary complex with importin beta, which explains the nonrequirement of importin beta for the nuclear transport of CaMKIV. The cytoplasmic microinjection of importin alpha-DeltaIBB enhanced the rate of nuclear translocation of CaMKIV in vivo. This is the first report to demonstrate definitely that mammalian importin alpha solely carries a cargo protein into the nucleus without utilizing the classical importin beta-dependent transport system.
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Affiliation(s)
- Ippei Kotera
- Department of Cell Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Toshihiro Sekimoto
- Department of Cell Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Yoichi Miyamoto
- Department of Frontier Biosciences, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Takuya Saiwaki
- Department of Cell Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Emi Nagoshi
- Department of Cell Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Hiroyuki Sakagami
- Department of Cell Biology, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, Japan
| | - Hisatake Kondo
- Department of Cell Biology, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, Japan
| | - Yoshihiro Yoneda
- Department of Cell Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
- Department of Frontier Biosciences, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
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24
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Truttmann AC, Ashraf Q, Mishra OP, Delivoria-Papadopoulos M. Effect of hypoxia on protein phosphatase 2A activity, subcellular distribution and expression in cerebral cortex of newborn piglets. Neuroscience 2004; 127:355-63. [PMID: 15262326 DOI: 10.1016/j.neuroscience.2004.05.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2004] [Indexed: 11/27/2022]
Abstract
Protein phosphatase (PP) 2A (PP2A), a major serine/threonine phosphatase highly active in the brain, is known to regulate programmed cell death by different mechanisms including downregulation of Ca++/calmodulin-dependent kinase IV (CaMK IV). Previous studies have shown that CaMK IV activity is increased following cerebral hypoxia. In the present study, we tested the hypothesis that PP2A activity and expression in neuronal nuclei are decreased following hypoxia in newborn piglets. PP and PP2A activities were determined in cerebral subcellular fractions spectrophotometrically using a serine phosphopeptide in the presence or absence of microcystine. The activity of CaMK IV in neuronal nuclei was determined by 33P-incorporation into syntide 2 in the presence or absence of either 1 mM EGTA or 0.8 mM CaCl2 and 1 mM calmodulin. The expressions of PP2A and CaMK IV were measured using Western blot. Following hypoxia, nuclear Ca++-dependent kinase IV activity increased two-fold (P<0.001), whereas PP2A and PP activities significantly decreased (P<0.05) in the neuronal nuclei and membranes but not in the cytosol (P=NS). The distribution of the activity of PP2A was 60% in the cytosol, 35% in membranes and 5% in the neuronal nuclei. The expression of PP2A protein showed a 14% increase and for CaMK IV protein a 100% increase during hypoxia. We propose that due to the decreased activity of PP and PP2A following hypoxia in the neuronal nuclei there is a shift in the balance of the phosphorylation/dephosphorylation system toward increased phosphorylated state thereby increasing activity of the nuclear CaMK IV, modulator of programmed cell death. Since there is only slight increase in the PP2A protein expression, we conclude that the changes observed in the activity of PP2A are due to hypoxia-induced modification of the enzyme itself. We also provide evidence that PP2A is a potential regulator of CaMK IV during hypoxia.
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Affiliation(s)
- A C Truttmann
- Division of Neonatology, Department of Pediatrics, University Hospital Lausanne, CHUV, 1011, Lausanne, Switzerland.
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25
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Carey MB, Matsumoto SG. Spontaneous calcium transients are required for neuronal differentiation of murine neural crest. Dev Biol 1999; 215:298-313. [PMID: 10545239 DOI: 10.1006/dbio.1999.9433] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have shown that cultured mouse neural crest (NC) cells exhibit transient increases in intracellular calcium. Up to 50% of the cultured NC-derived cells exhibited calcium transients during the period of neuronal differentiation. As neurogenic activity declined, so did the percentage of active NC-derived cells and their calcium spiking frequency. The decrease in calcium transient activity correlated with a decreased sensitivity to thimerosal, which sensitizes inositol 1,4,5-triphosphate receptors. Thimerosal increased the frequency of oscillations in active NC-derived cells and induced them in a subpopulation of quiescent cells. As neurogenesis ended, NC-derived cells became nonresponsive to thimerosal. Using the expression of time-dependent neuronal traits, we determined that neurons exhibited spontaneous calcium transients as early as a neuronal phenotype could be detected and continued through the acquisition of caffeine sensitivity, soon after which calcium transient activity stopped. A subpopulation of nonneuronal NC-derived cells exhibited calcium transient activity within the same time frame as neurogenesis in culture. Exposing NC-derived cells to 20 mM Mg(2+) blocked calcium transient activity and reduced neuronal number without affecting the survival of differentiated neurons. Using lineage-tracing analysis, we found that 50% of active NC-derived cells gave rise to clones containing neurons, while inactive cells did not. We hypothesize that calcium transient activity establishes a neuronal competence for undifferentiated NC cells.
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Affiliation(s)
- M B Carey
- Department of Biological Structure and Function, Oregon Health Sciences University, Portland, Oregon 97201, USA
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