101
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Sesay JS, Gyapong RNK, Najafi LT, Kabler SL, Diz DI, Howlett AC, Awumey EM. Gαi/o-dependent Ca(2+) mobilization and Gαq-dependent PKCα regulation of Ca(2+)-sensing receptor-mediated responses in N18TG2 neuroblastoma cells. Neurochem Int 2015; 90:142-51. [PMID: 26190181 DOI: 10.1016/j.neuint.2015.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 06/24/2015] [Accepted: 07/14/2015] [Indexed: 01/14/2023]
Abstract
A functional Ca(2+)-sensing receptor (CaS) is expressed endogenously in mouse N18TG2 neuroblastoma cells, and sequence analysis of the cDNA indicates high homology with both rat and human parathyroid CaS cDNAs. The CaS in N18TG2 cells appears as a single immunoreactive protein band at about 150 kDa on Western blots, consistent with native CaS from dorsal root ganglia. Both wild type (WT) and Gαq antisense knock-down (KD) cells responded to Ca(2+) and calindol, a positive allosteric modulator of the CaS, with a transient increase in intracellular Ca(2+) concentration ([Ca(2+)]i), which was larger in the Gαq KD cells. Stimulation with 1 mM extracellular Ca(2+) (Ca(2+)e) increased [Ca(2+)]i in N18TG2 Gαq KD compared to WT cells. Ca(2+) mobilization was dependent on pertussis toxin-sensitive Gαi/o proteins and reduced by 30 μM 2-amino-ethyldiphenyl borate and 50 μM nifedipine to the same plateau levels in both cell types. Membrane-associated PKCα and p-PKCα increased with increasing [Ca(2+)]e in WT cells, but decreased in Gαq KD cells. Treatment of cells with 1 μM Gӧ 6976, a Ca(2+)-specific PKC inhibitor reduced Ca(2+) mobilization and membrane-associated PKCα and p-PKCα in both cell types. The results indicate that the CaS-mediated increase in [Ca(2+)]i in N18TG2 cells is dependent on Gαi/o proteins via inositol-1,4,5-triphosphate (IP3) channels and store-operated Ca(2+) entry channels, whereas modulation of CaS responses involving PKCα phosphorylation and translocation to the plasma membrane occurs via a Gαq mechanism.
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Affiliation(s)
- John S Sesay
- Cardiovascular Disease Research Program, Julius L Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707, USA; Department of Biology, North Carolina Central University, Durham, NC 27707, USA; Department of Physiology and Pharmacology and Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Reginald N K Gyapong
- Cardiovascular Disease Research Program, Julius L Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707, USA
| | - Leila T Najafi
- Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, MO 63104, USA
| | - Sandra L Kabler
- Department of Physiology and Pharmacology and Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Debra I Diz
- Department of Physiology and Pharmacology and Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; Hypertension & Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Allyn C Howlett
- Department of Biology, North Carolina Central University, Durham, NC 27707, USA; Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, MO 63104, USA; Department of Physiology and Pharmacology and Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; Hypertension & Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Emmanuel M Awumey
- Cardiovascular Disease Research Program, Julius L Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707, USA; Department of Biology, North Carolina Central University, Durham, NC 27707, USA; Department of Physiology and Pharmacology and Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; Hypertension & Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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102
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Luderman KD, Chen R, Ferris MJ, Jones SR, Gnegy ME. Protein kinase C beta regulates the D₂-like dopamine autoreceptor. Neuropharmacology 2015; 89:335-41. [PMID: 25446677 DOI: 10.1016/j.neuropharm.2014.10.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 10/03/2014] [Accepted: 10/07/2014] [Indexed: 01/15/2023]
Abstract
The focus of this study was the regulation of the D2-like dopamine autoreceptor (D2 autoreceptor) by protein kinase Cβ, a member of the protein kinase C (PKC) family. Together with the dopamine transporter, the D2 autoreceptor regulates the level of extracellular dopamine and thus dopaminergic signaling. PKC regulates neuronal signaling via several mechanisms, including desensitizing autoreceptors to increase the release of several different neurotransmitters. Here, using both PKCβ(-/-) mice and specific PKCβ inhibitors, we demonstrated that a lack of PKCβ activity enhanced the D2 autoreceptor-stimulated decrease in dopamine release following both chemical and electrical stimulations. Inhibition of PKCβ increased surface localization of D2R in mouse striatal synaptosomes, which could underlie the greater sensitivity to quinpirole following inhibition of PKCβ. PKCβ(-/-) mice displayed greater sensitivity to the quinpirole-induced suppression of locomotor activity, demonstrating that the regulation of the D2 autoreceptor by PKCβ is physiologically significant. Overall, we have found that PKCβ downregulates the D2 autoreceptor, providing an additional layer of regulation for dopaminergic signaling. We propose that in the absence of PKCβ activity, surface D2 autoreceptor localization and thus D2 autoreceptor signaling is increased, leading to less dopamine in the extracellular space and attenuated dopaminergic signaling.
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Affiliation(s)
- Kathryn D Luderman
- Department of Pharmacology, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI, 48109-5632, USA.
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103
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Abstract
The protein kinase C (PKC) family of serine/threonine protein kinases share structural homology, while exhibiting substantial functional diversity. PKC isoforms are ubiquitously expressed in tissues which makes it difficult to define roles for individual isoforms, with complexity compounded by the finding that PKC isoforms can co-operate with or antagonize other PKC family members. A number of studies suggest the involvement of PKC family members in regulating leukaemic cell survival and proliferation. Chronic lymphocytic leukaemia (CLL), the most common leukaemia in the Western world, exhibits dysregulated expression of PKC isoforms, with recent reports indicating that PKCβ and δ play a critical role in B-cell development, due to their ability to link the B-cell receptor (BCR) with downstream signalling pathways. Given the prognostic significance of the BCR in CLL, inhibition of these BCR/PKC-mediated signalling pathways is of therapeutic relevance. The present review discusses the emerging role of PKC isoforms in the pathophysiology of CLL and assesses approaches that have been undertaken to modulate PKC activity.
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104
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Boudreault PL, Mattler JK, Wender PA. Studies on the regio- and diastereo-selective epoxidation of daphnanes and tiglianes. Tetrahedron Lett 2015; 56:3423-3427. [PMID: 26034334 PMCID: PMC4449265 DOI: 10.1016/j.tetlet.2015.01.126] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Daphnanes and tiglianes are diterpenes with a shared tricyclic 5-7-6 ring system. Many members exhibit significant biological activities often associated with protein kinase C signaling. Many of these natural products (~100) have a C6-C7 α-epoxide whose influence on biological activity is little studied. Using the more readily available phorbol ester PDBu as a test substrate, we report an efficient, and potentially general, α-epoxidation method based on a vanadium-catalyzed asymmetric epoxidation with bishydroxamic acid (BHA) ligands.
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Affiliation(s)
- Pierre-Luc Boudreault
- Department of Chemistry, Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305-5080, USA
| | - Jennifer K. Mattler
- Department of Chemistry, Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305-5080, USA
| | - Paul A. Wender
- Department of Chemistry, Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305-5080, USA
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105
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El-Yazbi AF, Abd-Elrahman KS, Moreno-Dominguez A. PKC-mediated cerebral vasoconstriction: Role of myosin light chain phosphorylation versus actin cytoskeleton reorganization. Biochem Pharmacol 2015; 95:263-78. [DOI: 10.1016/j.bcp.2015.04.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 04/16/2015] [Indexed: 10/23/2022]
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106
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Park C, Kalinec F. PKCα-Mediated Signals Regulate the Motile Responses of Cochlear Outer Hair Cells. Biophys J 2015; 108:2171-80. [PMID: 25954875 PMCID: PMC4423042 DOI: 10.1016/j.bpj.2015.03.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 03/09/2015] [Accepted: 03/23/2015] [Indexed: 12/29/2022] Open
Abstract
There is strong evidence that changes in the actin/spectrin-based cortical cytoskeleton of outer hair cells (OHCs) regulate their motile responses as well as cochlear amplification, the process that optimizes the sensitivity and frequency selectivity of the mammalian inner ear. Since a RhoA/protein kinase C (PKC)-mediated pathway is known to inhibit the actin-spectrin interaction in other cell models, we decided to investigate whether this signaling cascade could also participate in the regulation of OHC motility. We used high-speed video microscopy and confocal microscopy to explore the effects of pharmacological activation of PKCα, PKCβI, PKCβII, PKCδ, PKCε, and PKCζ with lysophosphatidic acid (LPA) and their inhibition with bisindolylmaleimide I, as well as inhibition of RhoA and Rho-associated protein kinase (ROCK) with C3 and Y-27632, respectively. Motile responses were induced in isolated guinea pig OHCs by stimulation with an 8 V/cm external alternating electrical field as 50 Hz bursts of square wave pulses (100 ms on/off). We found that LPA increased expression of PKCα and PKCζ only, with PKCα, but not PKCζ, phosphorylating the cytoskeletal protein adducin of both Ser-726 and Thr-445. Interestingly, however, inhibition of PKCα reduced adducin phosphorylation only at Ser-726. We also determined that LPA activation of a PKCα-mediated signaling pathway simultaneously enhanced OHC electromotile amplitude and cell shortening, and facilitated RhoA/ROCK/LIMK1-mediated cofilin phosphorylation. Altogether, our results suggest that PKCα-mediated signals, probably via adducin-mediated inhibition of actin-spectrin binding and cofilin-mediated depolymerization of actin filaments, play an essential role in the homeostatic regulation of OHC motility and cochlear amplification.
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Affiliation(s)
- Channy Park
- Laboratory of Auditory Cell Biology, Department of Head & Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Federico Kalinec
- Laboratory of Auditory Cell Biology, Department of Head & Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California.
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107
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Domazet I, Holleran BJ, Richard A, Vandenberghe C, Lavigne P, Escher E, Leduc R, Guillemette G. Characterization of Angiotensin II Molecular Determinants Involved in AT1 Receptor Functional Selectivity. Mol Pharmacol 2015; 87:982-95. [PMID: 25808928 DOI: 10.1124/mol.114.097337] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/24/2015] [Indexed: 01/14/2023] Open
Abstract
The octapeptide angiotensin II (AngII) exerts a variety of cardiovascular effects through the activation of the AngII type 1 receptor (AT1), a G protein-coupled receptor. The AT1 receptor engages and activates several signaling pathways, including heterotrimeric G proteins Gq and G12, as well as the extracellular signal-regulated kinases (ERK) 1/2 pathway. Additionally, following stimulation, βarrestin is recruited to the AT1 receptor, leading to receptor desensitization. It is increasingly recognized that specific ligands selectively bind and favor the activation of some signaling pathways over others, a concept termed ligand bias or functional selectivity. A better understanding of the molecular basis of functional selectivity may lead to the development of better therapeutics with fewer adverse effects. In the present study, we developed assays allowing the measurement of six different signaling modalities of the AT1 receptor. Using a series of AngII peptide analogs that were modified in positions 1, 4, and 8, we sought to better characterize the molecular determinants of AngII that underlie functional selectivity of the AT1 receptor in human embryonic kidney 293 cells. The results reveal that position 1 of AngII does not confer functional selectivity, whereas position 4 confers a bias toward ERK signaling over Gq signaling, and position 8 confers a bias toward βarrestin recruitment over ERK activation and Gq signaling. Interestingly, the analogs modified in position 8 were also partial agonists of the protein kinase C (PKC)-dependent ERK pathway via atypical PKC isoforms PKCζ and PKCι.
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Affiliation(s)
- Ivana Domazet
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Brian J Holleran
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Alexandra Richard
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Camille Vandenberghe
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Pierre Lavigne
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Emanuel Escher
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Richard Leduc
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Gaétan Guillemette
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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108
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Loy BA, Lesser AB, Staveness D, Billingsley KL, Cegelski L, Wender PA. Toward a biorelevant structure of protein kinase C bound modulators: design, synthesis, and evaluation of labeled bryostatin analogues for analysis with rotational echo double resonance NMR spectroscopy. J Am Chem Soc 2015; 137:3678-85. [PMID: 25710634 DOI: 10.1021/jacs.5b00886] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protein kinase C (PKC) modulators are currently of great importance in preclinical and clinical studies directed at cancer, immunotherapy, HIV eradication, and Alzheimer's disease. However, the bound conformation of PKC modulators in a membrane environment is not known. Rotational echo double resonance (REDOR) NMR spectroscopy could uniquely address this challenge. However, REDOR NMR requires strategically labeled, high affinity ligands to determine interlabel distances from which the conformation of the bound ligand in the PKC-ligand complex could be identified. Here we report the first computer-guided design and syntheses of three bryostatin analogues strategically labeled for REDOR NMR analysis. Extensive computer analyses of energetically accessible analogue conformations suggested preferred labeling sites for the identification of the PKC-bound conformers. Significantly, three labeled analogues were synthesized, and, as required for REDOR analysis, all proved highly potent with PKC affinities (∼1 nM) on par with bryostatin. These potent and strategically labeled bryostatin analogues are new structural leads and provide the necessary starting point for projected efforts to determine the PKC-bound conformation of such analogues in a membrane environment, as needed to design new PKC modulators and understand PKC-ligand-membrane structure and dynamics.
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Affiliation(s)
- Brian A Loy
- †Department of Chemistry and ‡Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Adam B Lesser
- †Department of Chemistry and ‡Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Daryl Staveness
- †Department of Chemistry and ‡Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Kelvin L Billingsley
- †Department of Chemistry and ‡Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Lynette Cegelski
- †Department of Chemistry and ‡Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, United States
| | - Paul A Wender
- †Department of Chemistry and ‡Department of Chemical and Systems Biology, Stanford University, Stanford, California 94305, United States
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109
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Ma J, Li MY, Wang F, Tang J, Xiong AS. Genome-wide analysis of Dof family transcription factors and their responses to abiotic stresses in Chinese cabbage. BMC Genomics 2015; 16:33. [PMID: 25636232 PMCID: PMC4320540 DOI: 10.1186/s12864-015-1242-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 01/15/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chinese cabbage is an important leaf vegetable that experienced long-term cultivation and artificial selection. Dof (DNA-binding One Zinc Finger) transcription factors, with a highly conserved Dof domain, are members of a major plant-specific transcription factor family that play important roles in many plant biological processes. The Dof family transcription factors, one of the most important families of transcriptional regulators in higher plants, are involved in massive aspects of plant growth, development, and response to abiotic stresses. Our study will supply resources for understanding how Dof transcription factors respond to abiotic stress and the interaction network of these genes in tolerance mechanism. RESULTS In this study, we performed a comprehensive analysis of Dof family factors in Chinese cabbage. In total, 76 genes encoding BraDof family transcription factor were identified from Chinese cabbage, and those BraDof factors were divided into nine classes. Fifteen motifs were found based on Dof amino acid sequence alignments. Chromosome locations and gene duplications of BraDof family genes were also analyzed. Ten duplicate events of BraDof genes were discovered in Chinese cabbage chromosomes. The uneven distribution of BraDof genes in Brassica chromosomes may cause the expansion of BraDof genes. In the Dof family, 37 and 7 orthologous genes were identified between Chinese cabbage and Arabidopsis and between Chinese cabbage and Oryza sativa, respectively. The interaction networks of Dof factors in Chinese cabbage were also constructed. Expression profiles of nine selected genes from different nine classes subjected to four abiotic stresses (cold, heat, salt and drought) were further investigated by quantitative real-time PCR to obtain a better understanding of the functions and regulation mechanisms of BraDof family transcription factors in two Chinese cabbage varieties, 'Lubaisanhao' and 'Qingdao 87-114'. CONCLUSIONS Dof-family transcription factors were analyzed in genome of Chinese cabbage. Chromosomal locations showed that duplication might result in expansion. Response to abiotic stresses was elucidated in Chinese cabbage varieties. The results provide novel insights into the stress responses of BraDof genes and promote a better understanding of the construction and function of Dofs in Chinese cabbage.
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Affiliation(s)
- Jing Ma
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Meng-Yao Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Feng Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Jun Tang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Ai-Sheng Xiong
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
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110
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Valtcheva MV, Davidson S, Zhao C, Leitges M, Gereau RW. Protein kinase Cδ mediates histamine-evoked itch and responses in pruriceptors. Mol Pain 2015; 11:1. [PMID: 25558916 PMCID: PMC4298070 DOI: 10.1186/1744-8069-11-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 12/23/2014] [Indexed: 01/28/2023] Open
Abstract
Background Itch-producing compounds stimulate receptors expressed on small diameter fibers that innervate the skin. Many of the currently known pruritogen receptors are Gq Protein-Coupled Receptors (GqPCR), which activate Protein Kinase C (PKC). Specific isoforms of PKC have been previously shown to perform selective functions; however, the roles of PKC isoforms in regulating itch remain unclear. In this study, we investigated the novel PKC isoform PKCδ as an intracellular modulator of itch signaling in response to histamine and the non-histaminergic pruritogens chloroquine and β-alanine. Results Behavioral experiments indicate that PKCδ knock-out (KO) mice have a 40% reduction in histamine-induced scratching when compared to their wild type littermates. On the other hand, there were no differences between the two groups in scratching induced by the MRGPR agonists chloroquine or β-alanine. PKCδ was present in small diameter dorsal root ganglion (DRG) neurons. Of PKCδ-expressing neurons, 55% also stained for the non-peptidergic marker IB4, while a smaller percentage (15%) expressed the peptidergic marker CGRP. Twenty-nine percent of PKCδ-expressing neurons also expressed TRPV1. Calcium imaging studies of acutely dissociated DRG neurons from PKCδ-KO mice show a 40% reduction in the total number of neurons responsive to histamine. In contrast, there was no difference in the number of capsaicin-responsive neurons between KO and WT animals. Acute pharmacological inhibition of PKCδ with an isoform-specific peptide inhibitor (δV1-1) also significantly reduced the number of histamine-responsive sensory neurons. Conclusions Our findings indicate that PKCδ plays a role in mediating histamine-induced itch, but may be dispensable for chloroquine- and β-alanine-induced itch.
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Affiliation(s)
| | | | | | | | - Robert W Gereau
- Washington University Pain Center and Department of Anesthesiology, Washington University in St, Louis, 660 S, Euclid Ave, Box 8054, 63110 St, Louis, MO, USA.
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111
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Mesenchymal chemotaxis requires selective inactivation of myosin II at the leading edge via a noncanonical PLCγ/PKCα pathway. Dev Cell 2014; 31:747-60. [PMID: 25482883 DOI: 10.1016/j.devcel.2014.10.024] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/25/2014] [Accepted: 10/29/2014] [Indexed: 11/23/2022]
Abstract
Chemotaxis, migration toward soluble chemical cues, is critical for processes such as wound healing and immune surveillance and is exhibited by various cell types, from rapidly migrating leukocytes to slow-moving mesenchymal cells. To study mesenchymal chemotaxis, we observed cell migration in microfluidic chambers that generate stable gradients of platelet-derived growth factor (PDGF). Surprisingly, we found that pathways implicated in amoeboid chemotaxis, such as PI3K and mammalian target of rapamycin signaling, are dispensable for PDGF chemotaxis. Instead, we find that local inactivation of Myosin IIA, through a noncanonical Ser1/2 phosphorylation of the regulatory light chain, is essential. This site is phosphorylated by PKCα, which is activated by an intracellular gradient of diacylglycerol generated by PLCγ. Using a combination of live imaging and gradients of activators/inhibitors in the microfluidic chambers, we demonstrate that this signaling pathway and subsequent inhibition of Myosin II activity at the leading edge are required for mesenchymal chemotaxis.
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112
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Venter G, Polling S, Pluk H, Venselaar H, Wijers M, Willemse M, Fransen JAM, Wieringa B. Submembranous recruitment of creatine kinase B supports formation of dynamic actin-based protrusions of macrophages and relies on its C-terminal flexible loop. Eur J Cell Biol 2014; 94:114-27. [PMID: 25538032 DOI: 10.1016/j.ejcb.2014.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 11/05/2014] [Accepted: 11/06/2014] [Indexed: 12/20/2022] Open
Abstract
Subcellular partitioning of creatine kinase contributes to the formation of patterns in intracellular ATP distribution and the fuelling of cellular processes with a high and sudden energy demand. We have previously shown that brain-type creatine kinase (CK-B) accumulates at the phagocytic cup in macrophages where it is involved in the compartmentalized generation of ATP for actin remodeling. Here, we report that CK-B catalytic activity also helps in the formation of protrusive ruffle structures which are actin-dependent and abundant on the surface of both unstimulated and LPS-activated macrophages. Recruitment of CK-B to these structures occurred transiently and inhibition of the enzyme's catalytic activity with cyclocreatine led to a general smoothening of surface morphology as visualized by scanning electron microscopy. Comparison of the dynamics of distribution of YFP-tagged CK-mutants and isoforms by live imaging revealed that amino acid residues in the C-terminal segment (aa positions 323-330) that forms one of the protein's two mobile loops are involved in partitioning over inner regions of the cytosol and nearby sites where membrane protrusions occur during induction of phagocytic cup formation. Although wt CK-B, muscle-type CK (CK-M), and a catalytically dead CK-B-E232Q mutant with intact loop region were normally recruited from the cytosolic pool, no dynamic transition to the phagocytic cup area was seen for the CK-homologue arginine kinase and a CK-B-D326A mutant protein. Bioinformatics analysis helped us to predict that conformational flexibility of the C-terminal loop, independent of conformational changes induced by substrate binding or catalytic activity, is likely involved in exposing the enzyme for binding at or near the sites of membrane protrusion formation.
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Affiliation(s)
- Gerda Venter
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Saskia Polling
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Helma Pluk
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Hanka Venselaar
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Mietske Wijers
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Marieke Willemse
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Jack A M Fransen
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Bé Wieringa
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
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113
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Inglese J, Dranchak P, Moran JJ, Jang SW, Srinivasan R, Santiago Y, Zhang L, Guha R, Martinez N, MacArthur R, Cost GJ, Svaren J. Genome editing-enabled HTS assays expand drug target pathways for Charcot-Marie-tooth disease. ACS Chem Biol 2014; 9:2594-602. [PMID: 25188731 PMCID: PMC4245164 DOI: 10.1021/cb5005492] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Copy number variation resulting in
excess PMP22 protein causes
the peripheral neuropathy Charcot–Marie–Tooth disease,
type 1A. To broadly interrogate chemically sensitive transcriptional
pathways controlling PMP22 protein levels, we used the targeting precision
of TALEN-mediated genome editing to embed reporters within the genetic
locus harboring the Peripheral Myelin Protein 22 (Pmp22) gene. Using a Schwann cell line with constitutively high endogenous
levels of Pmp22, we obtained allelic insertion of secreted bioluminescent
reporters with sufficient signal to enable a 1536-well assay. Our
findings from the quantitative high-throughput screening (qHTS) of
several thousand drugs and clinically investigated compounds using
this assay design both overlapped and expanded results from a previous
assay using a randomly inserted reporter gene controlled by a single
regulatory element of the Pmp22 gene. A key difference
was the identification of a kinase-controlled inhibitory pathway of Pmp22 transcription revealed by the activity of the Protein
kinase C (PKC)-modulator bryostatin.
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Affiliation(s)
- James Inglese
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
- National
Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Patricia Dranchak
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - John J. Moran
- Department
of Comparative Biosciences, and Waisman Center, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Sung-Wook Jang
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Rajini Srinivasan
- Department
of Comparative Biosciences, and Waisman Center, University of Wisconsin, Madison, Wisconsin 53705, United States
| | | | - Lei Zhang
- Sangamo BioSciences, Richmond, California 94804, United States
| | - Rajarshi Guha
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Natalia Martinez
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Ryan MacArthur
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Gregory J. Cost
- Sangamo BioSciences, Richmond, California 94804, United States
| | - John Svaren
- Department
of Comparative Biosciences, and Waisman Center, University of Wisconsin, Madison, Wisconsin 53705, United States
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114
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Differential targeting of cPKC and nPKC decodes and regulates Ca2+ and lipid signalling. Biochem Soc Trans 2014; 42:1538-42. [DOI: 10.1042/bst20140239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Protein kinases C (PKCs) are ubiquitously expressed and play critical roles in a plethora of physiological and pathophysiological processes. Owing to PKCs’ highly conserved phosphorylation consensus sequence, it has been difficult to distinguish the role of individual PKC isoforms. Recently, the identification of novel membrane targeting via subcellularly targeted diacylglycerol production found for novel PKCs (nPKCs), together with a characterization of their putative functions, has shed new light on the specific roles of individual PKCs in cellular processes.
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115
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Garg R, Benedetti LG, Abera MB, Wang H, Abba M, Kazanietz MG. Protein kinase C and cancer: what we know and what we do not. Oncogene 2014; 33:5225-37. [PMID: 24336328 DOI: 10.1038/onc.2013.524] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/20/2013] [Accepted: 10/20/2013] [Indexed: 02/08/2023]
Abstract
Since their discovery in the late 1970s, protein kinase C (PKC) isozymes represent one of the most extensively studied signaling kinases. PKCs signal through multiple pathways and control the expression of genes relevant for cell cycle progression, tumorigenesis and metastatic dissemination. Despite the vast amount of information concerning the mechanisms that control PKC activation and function in cellular models, the relevance of individual PKC isozymes in the progression of human cancer is still a matter of controversy. Although the expression of PKC isozymes is altered in multiple cancer types, the causal relationship between such changes and the initiation and progression of the disease remains poorly defined. Animal models developed in the last years helped to better understand the involvement of individual PKCs in various cancer types and in the context of specific oncogenic alterations. Unraveling the enormous complexity in the mechanisms by which PKC isozymes have an impact on tumorigenesis and metastasis is key for reassessing their potential as pharmacological targets for cancer treatment.
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Affiliation(s)
- R Garg
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - L G Benedetti
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - M B Abera
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - H Wang
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - M Abba
- Centro de Investigaciones Inmunológicas Básicas y Aplicadas (CINIBA), Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - M G Kazanietz
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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116
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Reetz O, Stadler K, Strauss U. Protein kinase C activation mediates interferon-β-induced neuronal excitability changes in neocortical pyramidal neurons. J Neuroinflammation 2014; 11:185. [PMID: 25359459 PMCID: PMC4222407 DOI: 10.1186/s12974-014-0185-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 10/13/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cytokines are key players in the interactions of the immune and nervous systems. Recently, we showed that such interplay is mediated by type I interferons (IFNs), which elevate the excitability of neocortical pyramidal neurons. A line of indirect evidence suggested that modulation of multiple ion channels underlies the effect. However, which currents are principally involved and how the IFN signaling cascade is linked to the respective ion channels remains elusive. METHODS We tested several single and combined ionic current modulations using an in silico model of a neocortical layer 5 neuron. Subsequently we investigated resulting predictions by whole-cell patch-clamp recordings in layer 5 neurons of ex vivo neocortical rat brain slices pharmacologically reproducing or prohibiting neuronal IFN effects. RESULTS The amount and type of modulation necessary to replicate IFN effects in silico suggested protein kinase C (PKC) activation as link between the type I IFN signaling and ion channel modulations. In line with this, PKC activation with 4β-phorbol 12-myristate 13-acetate (4β-PMA) or Bryostatin1 augmented the excitability of neocortical layer 5 neurons comparable to IFN-β in our ex vivo recordings. In detail, both PKC activators attenuated the rheobase and increased the input-output gain as well as the input resistance, thereby augmenting the neuronal excitability. Similar to IFN-β they also left the threshold of action potential generation unaffected. In further support of PKC mediating type I IFN effects, IFN-β, 4β-PMA and Bryostatin1 reduced the amplitude of post-train after-hyperpolarizations in a similar manner. In conjunction with this finding, IFN-β reduced M-currents, which contribute to after-hyperpolarizations and are modulated by PKC. Finally, blocking PKC activation with GF109203X at the catalytic site or calphostin C at the regulatory site prevented the main excitatory effects of IFN-β. CONCLUSION Multiple ion channel modulations underlie the neuromodulatory effect of type I IFNs. PKC activation is both sufficient and necessary for mediating the effect, and links the IFN signaling cascade to the intrinsic ion channels. Therefore, we regard PKC activation as unitary mechanism for the neuromodulatory potential of type I IFNs in neocortical neurons.
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117
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Bastianetto S, Ménard C, Quirion R. Neuroprotective action of resveratrol. Biochim Biophys Acta Mol Basis Dis 2014; 1852:1195-201. [PMID: 25281824 DOI: 10.1016/j.bbadis.2014.09.011] [Citation(s) in RCA: 249] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/09/2014] [Accepted: 09/16/2014] [Indexed: 11/30/2022]
Abstract
Low-to-moderate red wine consumption appeared to reduce age-related neurological disorders including macular degeneration, stroke, and cognitive deficits with or without dementia. Resveratrol has been considered as one of the key ingredients responsible for the preventive action of red wine since the stilbene displays a neuroprotective action in various models of toxicity. Besides its well documented free radical scavenging and anti-inflammatory properties, resveratrol has been shown to increase the clearance of beta-amyloid, a key feature of Alzheimer's disease, and to modulate intracellular effectors associated with oxidative stress (e.g. heme oxygenase), neuronal energy homeostasis (e.g. AMP kinase), program cell death (i.e. AIF) and longevity (i.e. sirtuins). This article summarizes the most recent findings on mechanisms of action involved in the protective effects of this multi target polyphenol, and discusses its possible roles in the prevention of various age-related neurological disorders. This article is part of a Special Issue entitled: Resveratrol: Challenges in translating pre-clinical findings to improved patient outcomes.
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Affiliation(s)
- Stéphane Bastianetto
- Douglas Mental Health University Institute, McGill University, Montreal, QC H4H 1R3, Canada
| | - Caroline Ménard
- Douglas Mental Health University Institute, McGill University, Montreal, QC H4H 1R3, Canada; Department of Psychiatry, McGill University, Montreal, QC H3A 1A1, Canada; Laboratory of Neuroendocrinology of Aging, Centre Hospitalier de l'Université de Montréal Research Center, Montreal, QC H2X 0A9, Canada; Department of Medicine, University of Montreal, Montreal, QC H3T 1J4, Canada
| | - Rémi Quirion
- Douglas Mental Health University Institute, McGill University, Montreal, QC H4H 1R3, Canada; Department of Psychiatry, McGill University, Montreal, QC H3A 1A1, Canada.
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Szilagyi K, Meijer AB, Neele AE, Verkuijlen P, Leitges M, Dabernat S, Förster-Waldl E, Boztug K, Belot A, Kuijpers TW, Kraal G, de Winther MPJ, van den Berg TK. PKCδ is dispensible for oxLDL uptake and foam cell formation by human and murine macrophages. Cardiovasc Res 2014; 104:467-76. [DOI: 10.1093/cvr/cvu213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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119
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Wender PA, Staveness D. Improved protein kinase C affinity through final step diversification of a simplified salicylate-derived bryostatin analog scaffold. Org Lett 2014; 16:5140-3. [PMID: 25238640 PMCID: PMC4334251 DOI: 10.1021/ol502492b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
Bryostatin
1, in clinical
trials or preclinical development for cancer, Alzheimer’s disease,
and a first-of-its-kind strategy for HIV/AIDS eradication, is neither
readily available nor optimally suited for clinical use. In preceding
work, we disclosed a new class of simplified bryostatin analogs designed
for ease of access and tunable activity. Here we describe a final
step diversification strategy that provides, in only 25 synthetic
steps, simplified and tunable analogs with bryostatin-like PKC modulatory
activities.
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Affiliation(s)
- Paul A Wender
- Departments of Chemistry and Chemical and Systems Biology, Stanford University , Stanford, California 94305, United States
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120
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Wender PA, Nakagawa Y, Near KE, Staveness D. Computer-guided design, synthesis, and protein kinase C affinity of a new salicylate-based class of bryostatin analogs. Org Lett 2014; 16:5136-9. [PMID: 25238583 PMCID: PMC4334246 DOI: 10.1021/ol502491f] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Bryostatin 1 is in
clinical trials for the treatment of cancer
and Alzheimer’s disease and is a candidate for a first-in-class
approach to HIV/AIDS eradication. It is neither readily available
nor optimally suited for clinical use. Using a function oriented synthesis
strategy, a new class of bryostatin-inspired analogs was designed
with a simplified salicylate-derived subunit, enabling step-economical
synthesis (23 total steps) of agents exhibiting bryostatin-like affinity
to protein kinase C (PKC).
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Affiliation(s)
- Paul A Wender
- Departments of Chemistry and Chemical and Systems Biology, Stanford University , Stanford, California 94305, United States
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121
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Abstract
Protein kinases C (PKCs) are a family of serine/threonine kinases which act as key regulators in cell cycle progression and differentiation. Studies of the involvement of PKCs in cell proliferation showed that their role is dependent on cell models, cell cycle phases, timing of activation and localization. Indeed, PKCs can positively and negatively act on it, regulating entry, progression and exit from the cell cycle. In particular, the targets of PKCs resulted to be some of the key proteins involved in the cell cycle including cyclins, cyclin-dependent kinases (Cdks), Cip/Kip inhibitors and lamins. Several findings described roles for PKCs in the regulation of G1/S and G2/M checkpoints. As a matter of fact, data from independent laboratories demonstrated PKC-related modulations of cyclins D, leading to effects on the G1/S transition and differentiation of different cell lines. Moreover, interesting data were published on PKC-mediated phosphorylation of lamins. In addition, PKC isoenzymes can accumulate in the nuclei, attracted by different stimuli including diacylglycerol (DAG) fluctuations during cell cycle progression, and target lamins, leading to their disassembly at mitosis. In the present paper, we briefly review how PKCs could regulate cell proliferation and differentiation affecting different molecules related to cell cycle progression.
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122
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Dieni CA, Storey KB. Protein kinase C in the wood frog, Rana sylvatica: reassessing the tissue-specific regulation of PKC isozymes during freezing. PeerJ 2014; 2:e558. [PMID: 25210662 PMCID: PMC4157297 DOI: 10.7717/peerj.558] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 08/14/2014] [Indexed: 01/03/2023] Open
Abstract
The wood frog, Rana sylvatica, survives whole-body freezing and thawing each winter. The extensive adaptations required at the biochemical level are facilitated by alterations to signaling pathways, including the insulin/Akt and AMPK pathways. Past studies investigating changing tissue-specific patterns of the second messenger IP3 in adapted frogs have suggested important roles for protein kinase C (PKC) in response to stress. In addition to their dependence on second messengers, phosphorylation of three PKC sites by upstream kinases (most notably PDK1) is needed for full PKC activation, according to widely-accepted models. The present study uses phospho-specific immunoblotting to investigate phosphorylation states of PKC—as they relate to distinct tissues, PKC isozymes, and phosphorylation sites—in control and frozen frogs. In contrast to past studies where second messengers of PKC increased during the freezing process, phosphorylation of PKC tended to generally decline in most tissues of frozen frogs. All PKC isozymes and specific phosphorylation sites detected by immunoblotting decreased in phosphorylation levels in hind leg skeletal muscle and hearts of frozen frogs. Most PKC isozymes and specific phosphorylation sites detected in livers and kidneys also declined; the only exceptions were the levels of isozymes/phosphorylation sites detected by the phospho-PKCα/βII (Thr638/641) antibody, which remained unchanged from control to frozen frogs. Changes in brains of frozen frogs were unique; no decreases were observed in the phosphorylation levels of any of the PKC isozymes and/or specific phosphorylation sites detected by immunoblotting. Rather, increases were observed for the levels of isozymes/phosphorylation sites detected by the phospho-PKCα/βII (Thr638/641), phospho-PKCδ (Thr505), and phospho-PKCθ (Thr538) antibodies; all other isozymes/phosphorylation sites detected in brain remained unchanged from control to frozen frogs. The results of this study indicate a potential important role for PKC in cerebral protection during wood frog freezing. Our findings also call for a reassessment of the previously-inferred importance of PKC in other tissues, particularly in liver; a more thorough investigation is required to determine whether PKC activity in this physiological situation is indeed dependent on phosphorylation, or whether it deviates from the generally-accepted model and can be “overridden” by exceedingly high levels of second messengers, as has been demonstrated with certain PKC isozymes (e.g., PKCδ).
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Affiliation(s)
| | - Kenneth B Storey
- Institute of Biochemistry, Carleton University , Ottawa, Ontario , Canada
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123
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Li Y, Gorelik G, Strickland FM, Richardson BC. Oxidative stress, T cell DNA methylation, and lupus. Arthritis Rheumatol 2014; 66:1574-82. [PMID: 24577881 PMCID: PMC4141415 DOI: 10.1002/art.38427] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 02/13/2014] [Indexed: 12/30/2022]
Abstract
Objective Lupus develops when genetically predisposed people encounter environmental agents, such as ultraviolet light, silica, infections, and cigarette smoke, that cause oxidative stress, but how oxidative damage modifies the immune system to cause lupus flares is unknown. We previously showed that inhibiting DNA methylation in CD4+ T cells by blocking ERK pathway signaling is sufficient to alter gene expression, and that the modified cells cause lupus-like autoimmunity in mice. We also reported that T cells from patients with active lupus have decreased ERK pathway signaling, have decreased DNA methylation, and overexpress genes normally suppressed by DNA methylation. This study was undertaken to test whether oxidizing agents decrease ERK pathway signaling in T cells, decrease DNA methyltransferase levels, and cause demethylation and overexpression of T cell genes similar to that found in T cells from patients with active lupus. Methods CD4+ T cells were treated with the oxidizers H2O2 or ONOO−. Effects on ERK pathway signaling were measured by immunoblotting, DNA methyltransferase 1 (DNMT-1) levels were measured by reverse transcriptase–polymerase chain reaction (RT-PCR), and the methylation and expression of T cell genes were measured using flow cytometry, RT-PCR, and bisulfite sequencing. Results H2O2 and ONOO− inhibited ERK pathway signaling in T cells by inhibiting the upstream regulator protein kinase Cδ, decreased DNMT-1 levels, and caused demethylation and overexpression of genes previously shown to be suppressed by DNA methylation in T cells from patients with active lupus. Conclusion Our findings indicate that oxidative stress may contribute to human lupus flares by inhibiting ERK pathway signaling in T cells to decrease DNMT-1 and cause DNA demethylation.
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124
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Borriello F, Granata F, Varricchi G, Genovese A, Triggiani M, Marone G. Immunopharmacological modulation of mast cells. Curr Opin Pharmacol 2014; 17:45-57. [PMID: 25063971 DOI: 10.1016/j.coph.2014.07.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 07/02/2014] [Accepted: 07/04/2014] [Indexed: 12/31/2022]
Abstract
Mast cells produce a wide spectrum of mediators and they have been implicated in several physiopathological conditions (e.g. allergic reactions and certain tumors). Pharmacologic agents that modulate the release of mediators from mast cells has helped to elucidate the biochemical mechanisms by which immunological and non-immunological stimuli activate these cells. Furthermore, the study of surface receptors and signaling pathways associated with mast cell activation revealed novel pharmacologic targets. Thus, the development of pharmacologic agents based on this new wave of knowledge holds promise for the treatment of several mast cell-mediated disorders.
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Affiliation(s)
- Francesco Borriello
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, School of Medicine, Via Pansini 5, 80131 Naples, Italy
| | - Francescopaolo Granata
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, School of Medicine, Via Pansini 5, 80131 Naples, Italy
| | - Gilda Varricchi
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, School of Medicine, Via Pansini 5, 80131 Naples, Italy
| | - Arturo Genovese
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, School of Medicine, Via Pansini 5, 80131 Naples, Italy
| | - Massimo Triggiani
- Division of Allergy and Clinical Immunology, University of Salerno, School of Medicine, Salerno, Italy
| | - Gianni Marone
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, School of Medicine, Via Pansini 5, 80131 Naples, Italy.
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125
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Pu X, Wang L, Chang JY, Hildebrandt MAT, Ye Y, Lu C, Skinner HD, Niu N, Jenkins GD, Komaki R, Minna JD, Roth JA, Weinshilboum RM, Wu X. Inflammation-related genetic variants predict toxicity following definitive radiotherapy for lung cancer. Clin Pharmacol Ther 2014; 96:609-15. [PMID: 25054431 PMCID: PMC4206576 DOI: 10.1038/clpt.2014.154] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 07/16/2014] [Indexed: 12/25/2022]
Abstract
Definitive radiotherapy improves locoregional control and survival in inoperable non-small cell lung cancer (NSCLC) patients. However, radiation-induced toxicities (pneumonitis/esophagitis) are common dose-limiting inflammatory conditions. We therefore conducted a pathway-based analysis to identify inflammation-related SNPs associated with radiation-induced pneumonitis or esophagitis. 11,930 SNPs were genotyped in 201 stage I-III NSCLC patients treated with definitive radiotherapy. Validation was performed in an additional 220 NSCLC cases. After validation, 19 SNPs remained significant. A polygenic risk score (PRS) was generated to summarize the effect from validated SNPs. Significant improvements in discriminative ability were observed by adding the PRS into the clinical/epidemiological variable-based model. We then used 277 lymphoblastoid cell-lines to assess radiation sensitivity and eQTL relationships of the identified SNPs. Three genes (PRKCE,DDX58 and TNFSF7) were associated with radiation sensitivity. We concluded that inflammation-related genetic variants could contribute to the development of radiation-induced toxicities. These loci could assist in predicting those unfavorable events.
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Affiliation(s)
- X Pu
- Department of Epidemiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - L Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA
| | - J Y Chang
- Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - M A T Hildebrandt
- Department of Epidemiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - Y Ye
- Department of Epidemiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - C Lu
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - H D Skinner
- Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - N Niu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA
| | - G D Jenkins
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA
| | - R Komaki
- Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - J D Minna
- Hamon Center for Therapeutic Oncology Research, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - J A Roth
- Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - R M Weinshilboum
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA
| | - X Wu
- Department of Epidemiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
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126
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Li Q, Zhu X, Ishikura S, Zhang D, Gao J, Sun Y, Contreras-Ferrat A, Foley KP, Lavandero S, Yao Z, Bilan PJ, Klip A, Niu W. Ca²⁺ signals promote GLUT4 exocytosis and reduce its endocytosis in muscle cells. Am J Physiol Endocrinol Metab 2014; 307:E209-24. [PMID: 24895284 DOI: 10.1152/ajpendo.00045.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Elevating cytosolic Ca(2+) stimulates glucose uptake in skeletal muscle, but how Ca(2+) affects intracellular traffic of GLUT4 is unknown. In tissue, changes in Ca(2+) leading to contraction preclude analysis of the impact of individual, Ca(2+)-derived signals. In L6 muscle cells stably expressing GLUT4myc, the Ca(2+) ionophore ionomycin raised cytosolic Ca(2+) and caused a gain in cell surface GLUT4myc. Extra- and intracellular Ca(2+) chelators (EGTA, BAPTA-AM) reversed this response. Ionomycin activated calcium calmodulin kinase II (CaMKII), AMPK, and PKCs, but not Akt. Silencing CaMKIIδ or AMPKα1/α2 partly reduced the ionomycin-induced gain in surface GLUT4myc, as did peptidic or small molecule inhibitors of CaMKII (CN21) and AMPK (Compound C). Compared with the conventional isoenzyme PKC inhibitor Gö6976, the conventional plus novel PKC inhibitor Gö6983 lowered the ionomycin-induced gain in cell surface GLUT4myc. Ionomycin stimulated GLUT4myc exocytosis and inhibited its endocytosis in live cells. siRNA-mediated knockdown of CaMKIIδ or AMPKα1/α2 partly reversed ionomycin-induced GLUT4myc exocytosis but did not prevent its reduced endocytosis. Compared with Gö6976, Gö6983 markedly reversed the slowing of GLUT4myc endocytosis triggered by ionomycin. In summary, rapid Ca(2+) influx into muscle cells accelerates GLUT4myc exocytosis while slowing GLUT4myc endocytosis. CaMKIIδ and AMPK stimulate GLUT4myc exocytosis, whereas novel PKCs reduce endocytosis. These results identify how Ca(2+)-activated signals selectively regulate GLUT4 exocytosis and endocytosis in muscle cells.
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Affiliation(s)
- Q Li
- Department of Immunology, Key Laboratory of Immuno Microenvironment and Disease of the Educational Ministry of China, Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - X Zhu
- Department of Immunology, Key Laboratory of Immuno Microenvironment and Disease of the Educational Ministry of China, Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - S Ishikura
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - D Zhang
- Department of Immunology, Key Laboratory of Immuno Microenvironment and Disease of the Educational Ministry of China, Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - J Gao
- Clinical Laboratory, First Teaching Hospital of Tianjin University of TCM, Tianjin, China; and
| | - Y Sun
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - A Contreras-Ferrat
- Advanced Center for Chronic Diseases and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas/Facultad Medicina; Universidad de Chile; Santiago, Chile
| | - K P Foley
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - S Lavandero
- Advanced Center for Chronic Diseases and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas/Facultad Medicina; Universidad de Chile; Santiago, Chile
| | - Z Yao
- Department of Immunology, Key Laboratory of Immuno Microenvironment and Disease of the Educational Ministry of China, Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - P J Bilan
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - A Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - W Niu
- Department of Immunology, Key Laboratory of Immuno Microenvironment and Disease of the Educational Ministry of China, Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China;
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127
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Falcone JA, Salameh TS, Yi X, Cordy BJ, Mortell WG, Kabanov AV, Banks WA. Intranasal administration as a route for drug delivery to the brain: evidence for a unique pathway for albumin. J Pharmacol Exp Ther 2014; 351:54-60. [PMID: 25027317 DOI: 10.1124/jpet.114.216705] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A variety of compounds will distribute into the brain when placed at the cribriform plate by intranasal (i.n.) administration. In this study, we investigated the ability of albumin, a protein that can act as a drug carrier but is excluded from brain by the blood-brain barrier, to distribute into the brain after i.n. administration. We labeled bovine serum albumin with [(125)I] ([(125)I]Alb) and studied its uptake into 11 brain regions and its entry into the blood from 5 minutes to 6 hours after i.n. administration. [(125)I]Alb was present throughout the brain at 5 minutes. Several regions showed distinct peaks in uptake that ranged from 5 minutes (parietal cortex) to 60 minutes (midbrain). About 2-4% of the i.n. [(125)I]Alb entered the bloodstream. The highest levels occurred in the olfactory bulb and striatum. Distribution was dose-dependent, with less taken up by whole brain, cortex, and blood at the higher dose of albumin. Uptake was selectively increased into the olfactory bulb and cortex by the fluid-phase stimulator PMA (phorbol 12-myristate 13-acetate), but inhibitors to receptor-mediated transcytosis, caveolae, and phosphoinositide 3-kinase were without effect. Albumin altered the distribution of radioactive leptin given by i.n. administration, decreasing uptake into the blood and by the cerebellum and increasing uptake by the hypothalamus. We conclude that [(125)I]Alb administered i.n. reaches all parts of the brain through a dose-dependent mechanism that may involve fluid-phase transcytosis and, as illustrated by leptin, can affect the delivery of other substances to the brain after their i.n. administration.
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Affiliation(s)
- Joseph A Falcone
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - Therese S Salameh
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - Xiang Yi
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - Benjamin J Cordy
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - William G Mortell
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - Alexander V Kabanov
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - William A Banks
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
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128
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Alcántara-Hernández R, Hernández-Méndez A, García-Sáinz JA. The phosphoinositide-dependent protein kinase 1 inhibitor, UCN-01, induces fragmentation: possible role of metalloproteinases. Eur J Pharmacol 2014; 740:88-96. [PMID: 25016091 DOI: 10.1016/j.ejphar.2014.06.057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/28/2014] [Accepted: 06/20/2014] [Indexed: 12/26/2022]
Abstract
Phosphoinositide-dependent protein kinase 1 (PDK1) is a key enzyme, master regulator of cellular proliferation and metabolism; it is considered a key target for pharmacological intervention. Using membranes obtained from DDT1 MF-2 cells, phospho-PDK1 was identified by Western blotting, as two major protein bands of Mr 58-68 kDa. Cell incubation with the PDK1 inhibitor, UCN-01, induced a time- and concentration-dependent decrease in the amount of phospho-PDK1 with a concomitant appearance of a ≈42 kDa phosphorylated fragment. Knocking down PDK1 diminished the amount of phospho-PDK1 detected in membranes, accompanied by similarly decreased fragment generation. UCN-01-induced fragment generation was also observed in membranes from cells stably expressing a myc-tagged PDK1 construct. Other PDK1 inhibitors were also tested: OSU-03012 induced a clear decrease in phospho-PDK1 and increased the presence of the phosphorylated fragment in membrane preparations; in contrast, GSK2334470 and staurosporine induced only marginal increases in the amount of PDK1 fragment. Galardin and batimastat, two metalloproteinase inhibitors, markedly attenuated inhibitor-induced PDK1 fragment generation. Metalloproteinases 2, 3, and 9 co-immunoprecipitated with myc-PDK1 under baseline conditions and this interaction was stimulated by UCN-01; batimastat also markedly diminished this effect of the PDK1 inhibitor. Our results indicate that a series of protein kinase inhibitors, namely UCN-01 and OSU-03012 and to a lesser extent GSK2334470 and staurosporine induce PDK1 fragmentation and suggest that metalloproteinases could participate in this effect.
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Key Words
- Batimastat (BB-94) (CID 5362422). Galardin (GM 6001) (PubChem CID 132519)
- GSK2334470, (3S,6R)-1-[6-(3-amino-1H-indazol-6-yl)-2-(methylamino)-4-pyrimidinyl]-N-cyclohexyl-6-methyl-3-piperidinecarboxamide. ) (PubChem CID 46215815)
- OSU-03012, (2-amino-N-[4-[5-(2-phenanthrenyl)-3-trifluoromethyl)-1H-pyrazol-1-yl]phenyl]-acetamide) (PubChem CID 10027278)
- PDK1
- Protein fragmentation
- Protein kinase
- Protein kinase inhibitor
- Staurosporine (PubChem CID 44259)
- UCN-01
- UCN-01, (7-hydroxystaurosporine (3R*,8S*, 9R*, 10R*,12R*)-2,3,9,10,11,12-hexahydro-3-hydroxy-9-methoxy-8-methyl-10-(methylamino)-8,12-epoxy-1H, 8H-2,7b,12a-triazadibenzo[a,g]-cyclonona[cde]triden-1-one) (PubChem CID 3078519)
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Affiliation(s)
- Rocío Alcántara-Hernández
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México DF 04510, México
| | - Aurelio Hernández-Méndez
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México DF 04510, México
| | - J Adolfo García-Sáinz
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-248, México DF 04510, México.
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129
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Ogbourne SM, Parsons PG. The value of nature's natural product library for the discovery of New Chemical Entities: the discovery of ingenol mebutate. Fitoterapia 2014; 98:36-44. [PMID: 25016953 DOI: 10.1016/j.fitote.2014.07.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/03/2014] [Accepted: 07/04/2014] [Indexed: 11/15/2022]
Abstract
In recent decades, 'Big Pharma' has invested billions of dollars into ingenious and innovative strategies designed to develop drugs using high throughput screening of small molecule libraries generated on the laboratory bench. Within the same time frame, screening of natural products by pharmaceutical companies has suffered an equally significant reduction. This is despite the fact that the complexity, functional diversity and druggability of nature's natural product library are considered by many to be superior to any library any team of scientists can prepare. It is therefore no coincidence that the number of New Chemical Entities reaching the market has also suffered a substantial decrease, leading to a productivity crisis within the pharmaceutical sector. In fact, the current dearth of New Chemical Entities reaching the market in recent decades might be a direct consequence of the strategic decision to move away from screening of natural products. Nearly 700 novel drugs derived from natural product New Chemical Entities were approved between 1981 and 2010; more than 60% of all approved drugs over the same time. In this review, we use the example of ingenol mebutate, a natural product identified from Euphorbia peplus and later approved as a therapy for actinic keratosis, as why nature's natural product library remains the most valuable library for discovery of New Chemical Entities and of novel drug candidates.
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Affiliation(s)
- Steven M Ogbourne
- GeneCology Research Centre, Faculty of Science, Health, Engineering and Education, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
| | - Peter G Parsons
- QIMR Berghofer Medical Research Institute, Locked Bag 2000, Post Office Royal Brisbane Hospital, QLD 4029, Australia.
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130
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Tisdale EJ, Shisheva A, Artalejo CR. Overexpression of atypical protein kinase C in HeLa cells facilitates macropinocytosis via Src activation. Cell Signal 2014; 26:1235-42. [PMID: 24582589 PMCID: PMC4149413 DOI: 10.1016/j.cellsig.2014.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 02/18/2014] [Indexed: 01/08/2023]
Abstract
Atypical protein kinase C (aPKC) is the first recognized kinase oncogene. However, the specific contribution of aPKC to cancer progression is unclear. The pseudosubstrate domain of aPKC is different from the other PKC family members, and therefore a synthetic peptide corresponding to the aPKC pseudosubstrate (aPKC-PS) sequence, which specifically blocks aPKC kinase activity, is a valuable tool to assess the role of aPKC in various cellular processes. Here, we learned that HeLa cells incubated with membrane permeable aPKC-PS peptide displayed dilated heterogeneous vesicles labeled with peptide that were subsequently identified as macropinosomes. A quantitative membrane binding assay revealed that aPKC-PS peptide stimulated aPKC recruitment to membranes and activated Src. Similarly, aPKC overexpression in transfected HeLa cells activated Src and induced macropinosome formation. Src-aPKC interaction was essential; substitution of the proline residues in aPKC that associate with the Src-SH3 binding domain rendered the mutant kinase unable to induce macropinocytosis in transfected cells. We propose that aPKC overexpression is a contributing factor to cell transformation by interacting with and consequently promoting Src activation and constitutive macropinocytosis, which increases uptake of extracellular factors, required for altered cell growth and accelerated cell migration.
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Affiliation(s)
- Ellen J Tisdale
- Department of Pharmacology, Wayne State University School of Medicine, 540 E. Canfield Ave., 6374 Scott Hall, Detroit, MI 48201, USA.
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield Ave., 5374 Scott Hall, Detroit, MI 48201, USA
| | - Cristina R Artalejo
- Department of Pharmacology, Wayne State University School of Medicine, 540 E. Canfield Ave., 6374 Scott Hall, Detroit, MI 48201, USA
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131
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Hoque M, Rentero C, Cairns R, Tebar F, Enrich C, Grewal T. Annexins — Scaffolds modulating PKC localization and signaling. Cell Signal 2014; 26:1213-25. [DOI: 10.1016/j.cellsig.2014.02.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 02/22/2014] [Indexed: 12/15/2022]
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132
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Soriano-Carot M, Quilis I, Bañó MC, Igual JC. Protein kinase C controls activation of the DNA integrity checkpoint. Nucleic Acids Res 2014; 42:7084-95. [PMID: 24792164 PMCID: PMC4066786 DOI: 10.1093/nar/gku373] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The protein kinase C (PKC) superfamily plays key regulatory roles in numerous cellular processes. Saccharomyces cerevisiae contains a single PKC, Pkc1, whose main function is cell wall integrity maintenance. In this work, we connect the Pkc1 protein to the maintenance of genome integrity in response to genotoxic stresses. Pkc1 and its kinase activity are necessary for the phosphorylation of checkpoint kinase Rad53, histone H2A and Xrs2 protein after deoxyribonucleic acid (DNA) damage, indicating that Pkc1 is required for activation of checkpoint kinases Mec1 and Tel1. Furthermore, Pkc1 electrophoretic mobility is delayed after inducing DNA damage, which reflects that Pkc1 is post-translationally modified. This modification is a phosphorylation event mediated by Tel1. The expression of different mammalian PKC isoforms at the endogenous level in yeast pkc1 mutant cells revealed that PKCδ is able to activate the DNA integrity checkpoint. Finally, downregulation of PKCδ activity in HeLa cells caused a defective activation of checkpoint kinase Chk2 when DNA damage was induced. Our results indicate that the control of the DNA integrity checkpoint by PKC is a mechanism conserved from yeast to humans.
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Affiliation(s)
- María Soriano-Carot
- Departament de Bioquímica i Biologia Molecular. Universitat de València, 46100 Burjassot (Valencia), Spain
| | - Inma Quilis
- Departament de Bioquímica i Biologia Molecular. Universitat de València, 46100 Burjassot (Valencia), Spain
| | - M Carmen Bañó
- Departament de Bioquímica i Biologia Molecular. Universitat de València, 46100 Burjassot (Valencia), Spain
| | - J Carlos Igual
- Departament de Bioquímica i Biologia Molecular. Universitat de València, 46100 Burjassot (Valencia), Spain
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133
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Targeted activation of conventional and novel protein kinases C through differential translocation patterns. Mol Cell Biol 2014; 34:2370-81. [PMID: 24732802 DOI: 10.1128/mcb.00040-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Activation of the two ubiquitous families of protein kinases, protein kinase A (PKA) and protein kinase C (PKC), is thought to be independently coupled to stimulation of Gαs and Gαq, respectively. Live-cell confocal imaging of protein kinase C fluorescent protein fusion constructs revealed that simultaneous activation of Gαs and Gαq resulted in a differential translocation of the conventional PKCα to the plasma membrane while the novel PKCδ was recruited to the membrane of the endoplasmic reticulum (ER). We demonstrate that the PKCδ translocation was driven by a novel Gαs-cyclic AMP-EPAC-RAP-PLCε pathway resulting in specific diacylglycerol production at the membrane of the ER. Membrane-specific phosphorylation sensors revealed that directed translocation resulted in phosphorylation activity confined to the target membrane. Specific stimulation of PKCδ caused phosphorylation of the inositol-1,4,5-trisphosphate receptor and dampening of global Ca(2+) signaling revealed by graded flash photolysis of caged inositol-1,4,5-trisphosphate. Our data demonstrate a novel signaling pathway enabling differential decoding of incoming stimuli into PKC isoform-specific membrane targeting, significantly enhancing the versatility of cyclic AMP signaling, thus demonstrating the possible interconnection between the PKA and PKC pathways traditionally treated independently. We thus provide novel and elementary understanding and insights into intracellular signaling events.
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134
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Building bridges toward invasion: tumor promoter treatment induces a novel protein kinase C-dependent phenotype in MCF10A mammary cell acini. PLoS One 2014; 9:e90722. [PMID: 24599099 PMCID: PMC3944432 DOI: 10.1371/journal.pone.0090722] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 02/03/2014] [Indexed: 12/02/2022] Open
Abstract
The potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) alters many cellular processes through activation of its receptor protein kinase C (PKC), including gene expression, cell cycle, and the regulation of cell morphology, raising an important question for developing targeted methods to prevent cancer: which effects of TPA are crucial for carcinogenesis? To address this question, we studied TPA action in the 3-dimensional (3D) MCF10A human breast epithelial cell system, which models important features of in vivo epithelial tissue including growth constraints, structural organization of cells, and establishment of a basement membrane. MCF10A cells, which are immortalized but nontumorigenic, form hollow, spheroid structures in 3D culture referred to as acini. The development of normal acini requires the tight spatiotemporal regulation of cellular proliferation, polarization, apoptosis, and growth arrest. Treatment of MCF10A acini with TPA caused the appearance of multi-acinar structures. Surprisingly, this phenotype did not involve an increase in cell number or major changes in cell death, and polarization. Instead, live cell and confocal microscopy revealed that TPA stimulates MCF10A acini to aggregate. TPA induces the PKC-dependent production of actin-based protrusions, which leads to the formation of cellular bridges between acini, the clustering of acini, and allows cells to move into adjacent acini. During this process, the integrity of the laminin V basement membrane is disrupted, while E-cadherin-based cell-cell contacts remain intact. Altogether, our results show that under the biochemical and structural constraints of epithelial tissue, as modeled by the 3D MCF10A system, TPA induces a novel PKC-dependent phenotype that resembles local invasion. Of the many effects caused by TPA, these studies highlight the aggressive production of actin-based cellular protrusions as a potentially important event along the pathway to carcinogenesis.
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135
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Isoforms of protein kinase C involved in phorbol ester-induced sphingosine 1-phosphate receptor 1 phosphorylation and desensitization. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:327-34. [DOI: 10.1016/j.bbamcr.2013.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 11/04/2013] [Accepted: 11/07/2013] [Indexed: 12/11/2022]
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136
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Armani F, Andersen ML, Galduróz JCF. Tamoxifen use for the management of mania: a review of current preclinical evidence. Psychopharmacology (Berl) 2014; 231:639-49. [PMID: 24441937 DOI: 10.1007/s00213-013-3397-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 12/04/2013] [Indexed: 12/13/2022]
Abstract
RATIONALE Preliminary data on the efficacy of tamoxifen in reducing manic symptoms of bipolar disorder (BD) suggest that this agent may be a potential treatment for the management of this psychiatric disorder. However, the antimanic properties of tamoxifen have not been fully elucidated, hampering the development and/or use of mood-stabilising drugs that may share its same therapeutic mechanisms of action. Notably, we may gain a greater understanding of the neurobiological and therapeutic properties of tamoxifen by using suitable animal models of mania. OBJECTIVES Here, we review the preclinical studies that have evaluated the effects of tamoxifen to provide an overview of the current progress in our understanding of its antimanic actions, highlighting the critical role of protein kinase C (PKC) as a therapeutic target for the treatment of BD. CONCLUSIONS To date, this field has struggled to make significant progress, and the organisation of an explicit battery of tests is a valuable tool for assessing a number of prominent facets of BD, which may provide a greater understanding of the entire scope of this disease.
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Affiliation(s)
- Fernanda Armani
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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137
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Luu W, Zerenturk EJ, Kristiana I, Bucknall MP, Sharpe LJ, Brown AJ. Signaling regulates activity of DHCR24, the final enzyme in cholesterol synthesis. J Lipid Res 2013; 55:410-20. [PMID: 24363437 DOI: 10.1194/jlr.m043257] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The role of signaling in regulating cholesterol homeostasis is gradually becoming more widely recognized. Here, we explored how kinases and phosphorylation sites regulate the activity of the enzyme involved in the final step of cholesterol synthesis, 3β-hydroxysterol Δ24-reductase (DHCR24). Many factors are known to regulate DHCR24 transcriptionally, but little is known about its posttranslational regulation. We developed a system to specifically test human ectopic DHCR24 activity in a model cell-line (Chinese hamster ovary-7) using siRNA targeted only to hamster DHCR24, thus ensuring that all activity could be attributed to the human enzyme. We determined the effect of known phosphorylation sites and found that mutating certain residues (T110, Y299, and Y507) inhibited DHCR24 activity. In addition, inhibitors of protein kinase C ablated DHCR24 activity, although not through a known phosphorylation site. Our data indicate a novel mechanism whereby DHCR24 activity is regulated by signaling.
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Affiliation(s)
- Winnie Luu
- School of Biotechnology and Biomolecular Sciences The University of New South Wales, Sydney, NSW 2052, Australia
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138
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Nociti FH, Foster BL, Tran AB, Dunn D, Presland RB, Wang L, Bhattacharyya N, Collins MT, Somerman MJ. Vitamin D represses dentin matrix protein 1 in cementoblasts and osteocytes. J Dent Res 2013; 93:148-54. [PMID: 24334408 DOI: 10.1177/0022034513516344] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Calcium and phosphorus homeostasis is achieved by interplay among hormones, including 1,25(OH)2D3 (1,25D), parathyroid hormone, and fibroblast growth factor 23 (FGF23), and their interactions with other proteins. For example, mutations in dentin matrix protein 1 (DMP-1) result in increased FGF23 and hypophosphatemic rickets. 1,25D is reported to modulate FGF23; thus, we hypothesized that 1,25D may be involved in modulating DMP-1 in an intermediary step. Murine cementoblasts (OCCM-30) and osteocyte-like cells (MLO-Y4 and MLO-A5), known to express DMP-1, were used to analyze effects of 1,25D on DMP-1 expression in vitro. DMP-1 mRNA levels decreased by 50% (p < .05) in the presence of 1,25D in all cell types, while use of a vitamin D receptor (VDR) agonist (EB1089) and antagonist (23S,25S)-DLAM-2P confirmed that VDR pathway activation was required for this response. Further analysis showed that histone deacetylase recruitment was necessary, but neither protein kinase A nor C pathways were required. In conclusion, our results support the hypothesis that 1,25D regulates DMP-1 expression through a VDR-dependent mechanism, possibly contributing to local changes in bone/tooth mineral homeostasis.
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Affiliation(s)
- F H Nociti
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
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139
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Belugin S, Diogenes AR, Patil MJ, Ginsburg E, Henry MA, Akopian AN. Mechanisms of transient signaling via short and long prolactin receptor isoforms in female and male sensory neurons. J Biol Chem 2013; 288:34943-55. [PMID: 24142695 PMCID: PMC3843105 DOI: 10.1074/jbc.m113.486571] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 10/09/2013] [Indexed: 01/01/2023] Open
Abstract
Prolactin (PRL) regulates activity of nociceptors and causes hyperalgesia in pain conditions. PRL enhances nociceptive responses by rapidly modulating channels in nociceptors. The molecular mechanisms underlying PRL-induced transient signaling in neurons are not well understood. Here we use a variety of cell biology and pharmacological approaches to show that PRL transiently enhanced capsaicin-evoked responses involve protein kinase C ε (PKCε) or phosphatidylinositol 3-kinase (PI3K) pathways in female rat trigeminal (TG) neurons. We next reconstituted PRL-induced signaling in a heterologous expression system and TG neurons from PRL receptor (PRLR)-null mutant mice by expressing rat PRLR-long isoform (PRLR-L), PRLR-short isoform (PRLR-S), or a mix of both. Results show that PRLR-S, but not PRLR-L, is capable of mediating PRL-induced transient enhancement of capsaicin responses in both male and female TG neurons. However, co-expression of PRLR-L with PRLR-S (1:1 ratio) leads to the inhibition of the transient PRL actions. Co-expression of PRLR-L deletion mutants with PRLR-S indicated that the cytoplasmic site adjacent to the trans-membrane domain of PRLR-L was responsible for inhibitory effects of PRLR-L. Furthermore, in situ hybridization and immunohistochemistry data indicate that in normal conditions, PRLR-L is expressed mainly in glia with little expression in rat sensory neurons (3-5%) and human nerves. The predominant PRLR form in TG neurons/nerves from rats and humans is PRLR-S. Altogether, PRL-induced transient signaling in sensory neurons is governed by PI3K or PKCε, mediated via the PRLR-S isoform, and transient effects mediated by PRLR-S are inhibited by presence of PRLR-L in these cells.
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Affiliation(s)
| | | | - Mayur J. Patil
- Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229 and
| | - Erika Ginsburg
- the NCI, National Institutes of Health, Bethesda, Maryland 20892
| | | | - Armen N. Akopian
- From the Departments of Endodontics and
- Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229 and
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Classical protein kinases C are regulated by concerted interaction with lipids: the importance of phosphatidylinositol-4,5-bisphosphate. Biophys Rev 2013; 6:3-14. [PMID: 28509956 DOI: 10.1007/s12551-013-0125-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/03/2013] [Indexed: 10/26/2022] Open
Abstract
Classical protein kinase C (PKC) enzymes are known to be important factors in cell physiology both in terms of health and disease. They are activated by triggering signals that induce their translocation to membranes. The consensus view is that several secondary messengers are involved in this activation, such as cytosolic Ca2+ and diacylglycerol. Cytosolic Ca2+ bridges the C2 domain to anionic phospholipids as phosphatidylserine in the membrane, and diacylglycerol binds to the C1 domain. Both diacylglycerol and the increase in Ca2+ concentration are assumed to arise from the extracellular signal that triggers the hydrolysis of phosphatidylinositol-4,5-bisphosphate. However, results obtained during the last decade indicate that this phosphoinositide itself is also responsible for modulating classical PKC activity and its localization in the plasma membrane.
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Bright DP, Smart TG. Protein kinase C regulates tonic GABA(A) receptor-mediated inhibition in the hippocampus and thalamus. Eur J Neurosci 2013; 38:3408-23. [PMID: 24102973 PMCID: PMC4165308 DOI: 10.1111/ejn.12352] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 07/24/2013] [Accepted: 08/08/2013] [Indexed: 12/14/2022]
Abstract
Tonic inhibition mediated by extrasynaptic GABAA receptors (GABAARs) is an important regulator of neuronal excitability. Phosphorylation by protein kinase C (PKC) provides a key mode of regulation for synaptic GABAARs underlying phasic inhibition; however, less attention has been focused on the plasticity of tonic inhibition and whether this can also be modulated by receptor phosphorylation. To address this issue, we used whole-cell patch clamp recording in acute murine brain slices at both room and physiological temperatures to examine the effects of PKC-mediated phosphorylation on tonic inhibition. Recordings from dentate gyrus granule cells in the hippocampus and dorsal lateral geniculate relay neurons in the thalamus demonstrated that PKC activation caused downregulation of tonic GABAAR-mediated inhibition. Conversely, inhibition of PKC resulted in an increase in tonic GABAAR activity. These findings were corroborated by experiments on human embryonic kidney 293 cells expressing recombinant α4β2δ GABAARs, which represent a key extrasynaptic GABAAR isoform in the hippocampus and thalamus. Using bath application of low GABA concentrations to mimic activation by ambient neurotransmitter, we demonstrated a similar inhibition of receptor function following PKC activation at physiological temperature. Live cell imaging revealed that this was correlated with a loss of cell surface GABAARs. The inhibitory effects of PKC activation on α4β2δ GABAAR activity appeared to be mediated by direct phosphorylation at a previously identified site on the β2 subunit, serine 410. These results indicate that PKC-mediated phosphorylation can be an important physiological regulator of tonic GABAAR-mediated inhibition.
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Affiliation(s)
- Damian P Bright
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
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Yang Q, Zhang XF, Van Goor D, Dunn AP, Hyland C, Medeiros N, Forscher P. Protein kinase C activation decreases peripheral actin network density and increases central nonmuscle myosin II contractility in neuronal growth cones. Mol Biol Cell 2013; 24:3097-114. [PMID: 23966465 PMCID: PMC3784383 DOI: 10.1091/mbc.e13-05-0289] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PKC activation enhances myosin II contractility in the central growth cone domain while decreasing actin density and increasing actin network flow rates in the peripheral domain. This dual mode of action has mechanistic implications for interpreting reported effects of PKC on growth cone guidance and neuronal regeneration. Protein kinase C (PKC) can dramatically alter cell structure and motility via effects on actin filament networks. In neurons, PKC activation has been implicated in repulsive guidance responses and inhibition of axon regeneration; however, the cytoskeletal mechanisms underlying these effects are not well understood. Here we investigate the acute effects of PKC activation on actin network structure and dynamics in large Aplysia neuronal growth cones. We provide evidence of a novel two-tiered mechanism of PKC action: 1) PKC activity enhances myosin II regulatory light chain phosphorylation and C-kinase–potentiated protein phosphatase inhibitor phosphorylation. These effects are correlated with increased contractility in the central cytoplasmic domain. 2) PKC activation results in significant reduction of P-domain actin network density accompanied by Arp2/3 complex delocalization from the leading edge and increased rates of retrograde actin network flow. Our results show that PKC activation strongly affects both actin polymerization and myosin II contractility. This synergistic mode of action is relevant to understanding the pleiotropic reported effects of PKC on neuronal growth and regeneration.
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Affiliation(s)
- Qing Yang
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511
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