51
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Xie F, Yi SL, Hao L, Zhang Y, Zhong JQ. Role of group I metabotropic glutamate receptors, mGluR1/mGluR5, in connexin43 phosphorylation and inhibition of gap junctional intercellular communication in H9c2 cardiomyoblast cells. Mol Cell Biochem 2014; 400:213-22. [DOI: 10.1007/s11010-014-2278-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 11/15/2014] [Indexed: 12/11/2022]
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Lee DY, Kim E, Lee YS, Ryu H, Park JY, Hwang EM. The cytosolic splicing variant of NELL2 inhibits PKCβ1 in glial cells. Biochem Biophys Res Commun 2014; 454:459-64. [PMID: 25450684 DOI: 10.1016/j.bbrc.2014.10.110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 10/21/2014] [Indexed: 11/29/2022]
Abstract
NELL2 is an abundant glycoprotein containing EGF-like domain in the neural tissues where it has multiple physiological functions by interacting with protein kinase C (PKC). There are two different splicing variant forms of NELL2 identified so far. One is secreted NELL2 (sNELL2) which is a neuron-specific variant and the other is cytosolic NELL2 (cNELL2) which is non-secreted splicing variant of NELL2. Although cNELL2 structure was well characterized, the expression pattern or the cellular function of cNELL2 is not fully determined. In this study, we found that cNELL2 specifically interacts with PKCβ isotypes and inhibits PKCβ1 through direct binding to the N-terminal pseudosubstrate domain of PKCβ1. Here, we also demonstrate that cNELL2 is predominantly expressed and has inhibitory effects on the PKC downstream signaling pathways in astrocytes thereby establishing cNELL2 as an endogenous inhibitor of PKCβ1 in glia.
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Affiliation(s)
- Da Yong Lee
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | - Eunju Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Young-Sun Lee
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Hwani Ryu
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 136-703, Republic of Korea.
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea; Neuroscience Program, University of Science and Technology (UST), Daejeon 305-350, Republic of Korea.
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IL-32θ downregulates CCL5 expression through its interaction with PKCδ and STAT3. Cell Signal 2014; 26:3007-15. [PMID: 25280942 DOI: 10.1016/j.cellsig.2014.09.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/15/2014] [Accepted: 09/15/2014] [Indexed: 01/11/2023]
Abstract
Interleukin-32 (IL-32) exists in several isoforms and plays an important role in inflammatory response. Recently, we identified a new isoform, IL-32θ, and performed a microarray analysis to identify IL-32θ-regulated genes in THP-1 myelomonocytic cells. Upon stimulating IL-32θ-expressing THP-1 cells with phorbol myristate acetate (PMA), we found that the CCL5 transcript level was significantly reduced. We confirmed the downregulation of CCL5 protein expression by using an enzyme-linked immunosorbent assay (ELISA). Because STAT3 phosphorylation on Ser727 by PKCδ is reported to suppress CCL5 protein expression, we examined whether IL-32θ-mediated STAT3 Ser727 phosphorylation occurs through an interaction with PKCδ. In this study, we first demonstrate that IL-32θ interacts with PKCδ and STAT3 using co-immunoprecipitation (Co-IP) and pulldown assay. Moreover, STAT3 was rarely phosphorylated on Ser727 in the absence of IL-32θ, leading to the binding of STAT3 to the CCL5 promoter. These results indicate that IL-32θ, through its interaction with PKCδ, downregulates CCL5 expression by mediating the phosphorylation of STAT3 on Ser727 to render it transcriptionally inactive. Therefore, similar to what we have reported for IL-32α and IL-32β, our data from this study suggests that the newly identified IL-32θ isoform also acts as an intracellular modulator of inflammation.
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Filla MS, Clark R, Peters DM. A syndecan-4 binding peptide derived from laminin 5 uses a novel PKCε pathway to induce cross-linked actin network (CLAN) formation in human trabecular meshwork (HTM) cells. Exp Cell Res 2014; 327:171-82. [PMID: 25128150 PMCID: PMC4164596 DOI: 10.1016/j.yexcr.2014.07.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 07/17/2014] [Accepted: 07/22/2014] [Indexed: 12/31/2022]
Abstract
In this study, we examined the role(s) of syndecan-4 in regulating the formation of an actin geodesic dome structure called a cross-linked actin network (CLAN) in which syndecan-4 has previously been localized. CLANs have been described in several different cell types, but they have been most widely studied in human trabecular meshwork (HTM) cells where they may play a key role in controlling intraocular pressure by regulating aqueous humor outflow from the eye. In this study we show that a loss of cell surface synedcan-4 significantly reduces CLAN formation in HTM cells. Analysis of HTM cultures treated with or without dexamethasone shows that laminin 5 deposition within the extracellular matrix is increased by glucocorticoid treatment and that a laminin 5-derived, syndecan-4-binding peptide (PEP75), induces CLAN formation in TM cells. This PEP75-induced CLAN formation was inhibited by heparin and the broad spectrum PKC inhibitor Ro-31-7549. In contrast, the more specific PKCα inhibitor Gö 6976 had no effect, thus excluding PKCα as a downstream effector of syndecan-4 signaling. Analysis of PKC isozyme expression showed that HTM cells also expressed both PKCγ and PKCε. Cells treated with a PKCε agonist formed CLANs while a PKCα/γ agonist had no effect. These data suggest that syndecan-4 is essential for CLAN formation in HTM cells and that a novel PKCε-mediated signaling pathway can regulate formation of this unique actin structure.
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Affiliation(s)
- Mark S Filla
- Department of Ophthalmology & Visual Sciences, Medical Science Center, 1300 University Avenue, Madison, WI 53706, United States.
| | - Ross Clark
- Department of Pathology & Laboratory Medicine, Medical Science Center, 1300 University Avenue, Madison, WI 53706, United States.
| | - Donna M Peters
- Department of Ophthalmology & Visual Sciences, Medical Science Center, 1300 University Avenue, Madison, WI 53706, United States; Department of Pathology & Laboratory Medicine, Medical Science Center, 1300 University Avenue, Madison, WI 53706, United States.
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55
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Filipiak K, Hidalgo M, Silvan JM, Fabre B, Carbajo RJ, Pineda-Lucena A, Ramos A, de Pascual-Teresa B, de Pascual-Teresa S. Dietary gallic acid and anthocyanin cytotoxicity on human fibrosarcoma HT1080 cells. A study on the mode of action. Food Funct 2014; 5:381-9. [PMID: 24413695 DOI: 10.1039/c3fo60465a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Gallic acid and anthocyanins are abundant plant food bioactives present in many fruits and vegetables, being especially important in the composition of berries. Gallic acid has been shown to possess cytotoxic properties in several cancer cell lines and to inhibit carcinogenesis in animal models. However, its mechanism of action is not yet fully understood. The aim of this study was to elucidate whether the observed inhibitory activity of gallic acid against gelatinases corresponds to its cytotoxic activity in HT1080 cells and to determine if anthocyanins could exhibit a similar behavior. Gallic acid and delphinidin-3-glucoside have shown selective cytotoxicity towards HT1080 cells. Further analysis by a migration and invasion assay showed anti-invasive activities of gallic acid, delphinidin and pelargonidin-3-glucosides. Zymographic analysis demonstrated the inhibitory activity of gallic acid at the level of secreted and activated gelatinases. Moreover, gallic acid inhibited MMP-2 and MMP-9 proteolytic activity with very similar potency. NMR and molecular modelling experiments confirmed the interaction of gallic acid with MMP-2, and suggested that it takes place within the catalytic center. In this work we give some new experimental data supporting the role of these compounds in the inhibition of metalloproteases as the mechanism for their cytotoxic activity against fibrosarcoma.
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Affiliation(s)
- Kamila Filipiak
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad CEU San Pablo, Urbanización Monteprincipe, 28668 Madrid, Spain
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56
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Vaughan EM, You JS, Elsie Yu HY, Lasek A, Vitale N, Hornberger TA, Bement WM. Lipid domain-dependent regulation of single-cell wound repair. Mol Biol Cell 2014; 25:1867-76. [PMID: 24790096 PMCID: PMC4055266 DOI: 10.1091/mbc.e14-03-0839] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 04/14/2014] [Accepted: 04/21/2014] [Indexed: 11/21/2022] Open
Abstract
After damage, cells reseal their plasma membrane and repair the underlying cortical cytoskeleton. Although many different proteins have been implicated in cell repair, the potential role of specific lipids has not been explored. Here we report that cell damage elicits rapid formation of spatially organized lipid domains around the damage site, with different lipids concentrated in different domains as a result of both de novo synthesis and transport. One of these lipids-diacylglycerol (DAG)-rapidly accumulates in a broad domain that overlaps the zones of active Rho and Cdc42, GTPases that regulate repair of the cortical cytoskeleton. Formation of the DAG domain is required for Cdc42 and Rho activation and healing. Two DAG targets, protein kinase C (PKC) β and η, are recruited to cell wounds and play mutually antagonistic roles in the healing process: PKCβ participates in Rho and Cdc42 activation, whereas PKCη inhibits Rho and Cdc42 activation. The results reveal an unexpected diversity in subcellular lipid domains and the importance of such domains for a basic cellular process.
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Affiliation(s)
- Emily M Vaughan
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706
| | - Jae-Sung You
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706
| | - Hoi-Ying Elsie Yu
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706
| | - Amber Lasek
- Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Integratives, Centre National de la Recherche Scientifique UPR 3212, and Université de Strasbourg, 67400 Strasbourg, France
| | - Troy A Hornberger
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706
| | - William M Bement
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
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Neuroprotective mechanism of ischemic postconditioning in mice: a possible relationship between protein kinase C and nitric oxide pathways. J Surg Res 2014; 189:174-83. [DOI: 10.1016/j.jss.2014.02.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/06/2014] [Accepted: 02/14/2014] [Indexed: 11/21/2022]
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Kim HR, Kim JM, Kim MS, Hwang JK, Park YJ, Yang SH, Kim HJ, Ryu DG, Lee DS, Oh H, Kim YC, Rhee YJ, Moon BS, Yun JM, Kwon KB, Lee YR. Saussurea lappa extract suppresses TPA-induced cell invasion via inhibition of NF-κB-dependent MMP-9 expression in MCF-7 breast cancer cells. Altern Ther Health Med 2014; 14:170. [PMID: 24885456 PMCID: PMC4229955 DOI: 10.1186/1472-6882-14-170] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 05/13/2014] [Indexed: 11/10/2022]
Abstract
Background Saussurea lappa (SL) has been used as a traditional herbal medicine to treat abdominal pain and tenesmus, and has been suggested to possess various biological activities, including anti-tumor, anti-ulcer, anti-inflammatory, anti-viral, and cardiotonic activities. The effect of SL on breast cancer metastasis, however, is unknown. Cell migration and invasion are crucial in neoplastic metastasis. Matrix metalloproteinase-9 (MMP-9), which degrades the extracellular matrix, is a major component in cancer cell invasion. Methods Cell viability was examined by MTT assay, whereas cell motility was measured by invasion assay. Western blot, Real-time PCR, and Zymography assays were used to investigate the inhibitory effects of ESL on matrix metalloproteinase-9 (MMP-9) expression level in MCF-7 cells. EMSA confirmed the inhibitory effects of ESL on DNA binding of NF- κB in MCF-7 cells. Results Cells threated with various concentrations of Saussurea lappa (ESL) for 24 h. Concentrations of 2 or 4 μM did not lead to a significant change in cell viability or morphology. Therefore, subsequent experiments utilized the optimal non-toxic concentration (2 or 4 μM) of ESL. In this study, we investigated the inhibitory effect of ethanol extract of ESL on MMP-9 expression and cell invasion in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MCF-7 cells. ESL inhibited the TPA-induced transcriptional activation of nuclear factor-kappa B (NF-κB). However, this result obtained that ESL did not block the TPA-induced phosphorylation of the kinases: p38, ERK, and JNK. Therefore, ELS-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of NF-kB pathway in MCF-7 cells. Conclusions These results indicate that ELS-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of NF-kB pathway in MCF-7 cells. Thus, ESL has potential for controlling breast cancer invasiveness in vitro.
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Joshi S, Singh AR, Zulcic M, Durden DL. A PKC-SHP1 signaling axis desensitizes Fcγ receptor signaling by reducing the tyrosine phosphorylation of CBL and regulates FcγR mediated phagocytosis. BMC Immunol 2014; 15:18. [PMID: 24886428 PMCID: PMC4017086 DOI: 10.1186/1471-2172-15-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/23/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fcγ receptors mediate important biological signals in myeloid cells including the ingestion of microorganisms through a process of phagocytosis. It is well-known that Fcγ receptor (FcγR) crosslinking induces the tyrosine phosphorylation of CBL which is associated with FcγR mediated phagocytosis, however how signaling molecules coordinate to desensitize these receptors is unclear. An investigation of the mechanisms involved in receptor desensitization will provide new insight into potential mechanisms by which signaling molecules may downregulate tyrosine phosphorylation dependent signaling events to terminate important signaling processes. RESULTS Using the U937IF cell line, we observed that FcγR1 crosslinking induces the tyrosine phosphorylation of CBL, which is maximal at 5 min. followed by a kinetic pattern of dephosphorylation. An investigation of the mechanisms involved in receptor desensitization revealed that pretreatment of U937IF or J774 cells with PMA followed by Fcγ receptor crosslinking results in the reduced tyrosine phosphorylation of CBL and the abrogation of downstream signals, such as CBL-CRKL binding, Rac-GTP activation and the phagocytic response. Pretreatment of J774 cells with GF109203X, a PKC inhibitor was observed to block dephosphorylation of CBL and rescued the phagocytic response. We demonstrate that the PKC induced desensitization of FcγR/ phagocytosis is associated with the inactivation of Rac-GTP, which is deactivated in a hematopoietic specific phosphatase SHP1 dependent manner following ITAM stimulation. The effect of PKC on FcγR signaling is augmented by the transfection of catalytically active SHP1 and not by the transfection of catalytic dead SHP1 (C124S). CONCLUSIONS Our results suggest a functional model by which PKC interacts with SHP1 to affect the phosphorylation state of CBL, the activation state of Rac and the negative regulation of ITAM signaling i.e. Fcγ receptor mediated phagocytosis. These findings suggest a mechanism for Fcγ receptor desensitization by which a serine-threonine kinase e.g. PKC downregulates tyrosine phosphorylation dependent signaling events via the reduced tyrosine phosphorylation of the complex adapter protein, CBL.
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Affiliation(s)
| | | | | | - Donald L Durden
- UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093, USA.
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60
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Saha K, Adhikary G, Kanade SR, Rorke EA, Eckert RL. p38δ regulates p53 to control p21Cip1 expression in human epidermal keratinocytes. J Biol Chem 2014; 289:11443-11453. [PMID: 24599959 PMCID: PMC4036280 DOI: 10.1074/jbc.m113.543165] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/28/2014] [Indexed: 11/06/2022] Open
Abstract
PKCδ suppresses keratinocyte proliferation via a mechanism that involves increased expression of p21(Cip1). However, the signaling mechanism that mediates this regulation is not well understood. Our present studies suggest that PKCδ activates p38δ leading to increased p21(Cip1) promoter activity and p21(Cip1) mRNA/protein expression. We further show that exogenously expressed p38δ increases p21(Cip1) mRNA and protein and that p38δ knockdown or expression of dominant-negative p38 attenuates this increase. Moreover, p53 is an intermediary in this regulation, as p38δ expression increases p53 mRNA, protein, and promoter activity, and p53 knockdown attenuates the activation. We demonstrate a direct interaction of p38δ with PKCδ and MEK3 and show that exogenous agents that suppress keratinocyte proliferation activate this pathway. We confirm the importance of this regulation using a stratified epidermal equivalent model, which mimics in vivo-like keratinocyte differentiation. In this model, PKCδ or p38δ knockdown results in reduced p53 and p21(Cip1) levels and enhanced cell proliferation. We propose that PKCδ activates a MEKK1/MEK3/p38δ MAPK cascade to increase p53 levels and p53 drives p21(Cip1) gene expression.
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Affiliation(s)
- Kamalika Saha
- Departments of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Gautam Adhikary
- Departments of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Santosh R Kanade
- Departments of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Ellen A Rorke
- Departments of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Richard L Eckert
- Departments of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201; Departments of Dermatology, University of Maryland School of Medicine, Baltimore, Maryland 21201; Departments of Obstetrics and Gynecology, and University of Maryland School of Medicine, Baltimore, Maryland 21201.
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61
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Ziemba BP, Li J, Landgraf KE, Knight JD, Voth GA, Falke JJ. Single-molecule studies reveal a hidden key step in the activation mechanism of membrane-bound protein kinase C-α. Biochemistry 2014; 53:1697-713. [PMID: 24559055 PMCID: PMC3971957 DOI: 10.1021/bi4016082] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
![]()
Protein
kinase C-α (PKCα) is a member of the conventional
family of protein kinase C isoforms (cPKCs) that regulate diverse
cellular signaling pathways, share a common activation mechanism,
and are linked to multiple pathologies. The cPKC domain structure
is modular, consisting of an N-terminal pseudosubstrate peptide, two
inhibitory domains (C1A and C1B), a targeting domain (C2), and a kinase
domain. Mature, cytoplasmic cPKCs are inactive until they are switched
on by a multistep activation reaction that occurs largely on the plasma
membrane surface. Often, this activation begins with a cytoplasmic
Ca2+ signal that triggers C2 domain targeting to the plasma
membrane where it binds phosphatidylserine (PS) and phosphatidylinositol
4,5-bisphosphate (PIP2). Subsequently, the appearance of
the signaling lipid diacylglycerol (DAG) activates the membrane-bound
enzyme by recruiting the inhibitory pseudosubstrate and one or both
C1 domains away from the kinase domain. To further investigate this
mechanism, this study has utilized single-molecule total internal
reflection fluorescence microscopy (TIRFM) to quantitate the binding
and lateral diffusion of full-length PKCα and fragments missing
specific domain(s) on supported lipid bilayers. Lipid binding events,
and events during which additional protein is inserted into the bilayer,
were detected by their effects on the equilibrium bound particle density
and the two-dimensional diffusion rate. In addition to the previously
proposed activation steps, the findings reveal a major, undescribed,
kinase-inactive intermediate. On bilayers containing PS or PS and
PIP2, full-length PKCα first docks to the membrane
via its C2 domain, and then its C1A domain embeds itself in the bilayer
even before DAG appears. The resulting pre-DAG intermediate with membrane-bound
C1A and C2 domains is the predominant state of PKCα while it
awaits the DAG signal. The newly detected, membrane-embedded C1A domain
of this pre-DAG intermediate confers multiple useful features, including
enhanced membrane affinity and longer bound state lifetime. The findings
also identify the key molecular step in kinase activation: because
C1A is already membrane-embedded in the kinase off state, recruitment
of C1B to the bilayer by DAG or phorbol ester is the key regulatory
event that stabilizes the kinase on state. More broadly, this study
illustrates the power of single-molecule methods in elucidating the
activation mechanisms and hidden regulatory states of membrane-bound
signaling proteins.
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Affiliation(s)
- Brian P Ziemba
- Department of Chemistry and Biochemistry and Molecular Biophysics Program, University of Colorado , Boulder, Colorado 80309-0596, United States
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KIM JEONGMI, NOH EUNMI, KIM MISEONG, HWANG JINKI, HWANG HONGYEON, RYU DOGON, KIM HYEJUNG, YU HONGNU, YOU YONGOUK, KIM JONGSUK, YOUN HYUNJO, KWON KANGBEOM, JUNG SUNGHOO, LEE YOUNGRAE. Decursin prevents TPA-induced invasion through suppression of PKCα/p38/NF-κB-dependent MMP-9 expression in MCF-7 human breast carcinoma cells. Int J Oncol 2014; 44:1607-13. [DOI: 10.3892/ijo.2014.2327] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 01/21/2014] [Indexed: 11/05/2022] Open
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Fogh BS, Multhaupt HAB, Couchman JR. Protein kinase C, focal adhesions and the regulation of cell migration. J Histochem Cytochem 2014; 62:172-84. [PMID: 24309511 PMCID: PMC3935447 DOI: 10.1369/0022155413517701] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/21/2013] [Indexed: 12/18/2022] Open
Abstract
Cell adhesion to extracellular matrix is a complex process involving protrusive activity driven by the actin cytoskeleton, engagement of specific receptors, followed by signaling and cytoskeletal organization. Thereafter, contractile and endocytic/recycling activities may facilitate migration and adhesion turnover. Focal adhesions, or focal contacts, are widespread organelles at the cell-matrix interface. They arise as a result of receptor interactions with matrix ligands, together with clustering. Recent analysis shows that focal adhesions contain a very large number of protein components in their intracellular compartment. Among these are tyrosine kinases, which have received a great deal of attention, whereas the serine/threonine kinase protein kinase C has received much less. Here the status of protein kinase C in focal adhesions and cell migration is reviewed, together with discussion of its roles and potential substrates.
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Affiliation(s)
- Betina S Fogh
- Department of Biomedical Sciences, University of Copenhagen, Denmark
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Li G, Wang Y. Protein kinase D: a new player among the signaling proteins that regulate functions in the nervous system. Neurosci Bull 2014; 30:497-504. [PMID: 24526660 DOI: 10.1007/s12264-013-1403-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 06/07/2013] [Indexed: 10/25/2022] Open
Abstract
Protein kinase D (PKD) is an evolutionarily-conserved family of protein kinases. It has structural, regulatory, and enzymatic properties quite different from the PKC family. Many stimuli induce PKD signaling, including G-protein-coupled receptor agonists and growth factors. PKD1 is the most studied member of the family. It functions during cell proliferation, differentiation, secretion, cardiac hypertrophy, immune regulation, angiogenesis, and cancer. Previously, we found that PKD1 is also critically involved in pain modulation. Since then, a series of studies performed in our lab and by other groups have shown that PKDs also participate in other processes in the nervous system including neuronal polarity establishment, neuroprotection, and learning. Here, we discuss the connections between PKD structure, enzyme function, and localization, and summarize the recent findings on the roles of PKD-mediated signaling in the nervous system.
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Affiliation(s)
- Gang Li
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, 100191, China
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Kudoh A, Takahama S, Sawasaki T, Ode H, Yokoyama M, Okayama A, Ishikawa A, Miyakawa K, Matsunaga S, Kimura H, Sugiura W, Sato H, Hirano H, Ohno S, Yamamoto N, Ryo A. The phosphorylation of HIV-1 Gag by atypical protein kinase C facilitates viral infectivity by promoting Vpr incorporation into virions. Retrovirology 2014; 11:9. [PMID: 24447338 PMCID: PMC3905668 DOI: 10.1186/1742-4690-11-9] [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] [Received: 07/25/2013] [Accepted: 01/12/2014] [Indexed: 12/14/2022] Open
Abstract
Background Human immunodeficiency virus type 1 (HIV-1) Gag is the main structural protein that mediates the assembly and release of virus-like particles (VLPs) from an infected cell membrane. The Gag C-terminal p6 domain contains short sequence motifs that facilitate virus release from the plasma membrane and mediate incorporation of the viral Vpr protein. Gag p6 has also been found to be phosphorylated during HIV-1 infection and this event may affect virus replication. However, the kinase that directs the phosphorylation of Gag p6 toward virus replication remains to be identified. In our present study, we identified this kinase using a proteomic approach and further delineate its role in HIV-1 replication. Results A proteomic approach was designed to systematically identify human protein kinases that potently interact with HIV-1 Gag and successfully identified 22 candidates. Among this panel, atypical protein kinase C (aPKC) was found to phosphorylate HIV-1 Gag p6. Subsequent LC-MS/MS and immunoblotting analysis with a phospho-specific antibody confirmed both in vitro and in vivo that aPKC phosphorylates HIV-1 Gag at Ser487. Computer-assisted structural modeling and a subsequent cell-based assay revealed that this phosphorylation event is necessary for the interaction between Gag and Vpr and results in the incorporation of Vpr into virions. Moreover, the inhibition of aPKC activity reduced the Vpr levels in virions and impaired HIV-1 infectivity of human primary macrophages. Conclusion Our current results indicate for the first time that HIV-1 Gag phosphorylation on Ser487 is mediated by aPKC and that this kinase may regulate the incorporation of Vpr into HIV-1 virions and thereby supports virus infectivity. Furthermore, aPKC inhibition efficiently suppresses HIV-1 infectivity in macrophages. aPKC may therefore be an intriguing therapeutic target for HIV-1 infection.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Akihide Ryo
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan.
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Lin G, Brownsey RW, MacLeod KM. Complex regulation of PKCβ2 and PDK-1/AKT by ROCK2 in diabetic heart. PLoS One 2014; 9:e86520. [PMID: 24466133 PMCID: PMC3896488 DOI: 10.1371/journal.pone.0086520] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 12/15/2013] [Indexed: 01/13/2023] Open
Abstract
Objectives The RhoA/ROCK pathway contributes to diabetic cardiomyopathy in part by promoting the sustained activation of PKCβ2 but the details of their interaction are unclear. The purpose of this study was to investigate if over-activation of ROCK in the diabetic heart leads to direct phosphorylation and activation of PKCβ2, and to determine if their interaction affects PDK-1/Akt signaling. Methods Regulation by ROCK of PKCβ2 and related kinases was investigated by Western blotting and co-immunoprecipitation in whole hearts and isolated cardiomyocytes from 12 to 14-week diabetic rats. Direct ROCK2 phosphorylation of PKCβ2 was examined in vitro. siRNA silencing was used to confirm role of ROCK2 in PKCβ2 phosphorylation in vascular smooth muscle cells cultured in high glucose. Furthermore, the effect of ROCK inhibition on GLUT4 translocation was determined in isolated cardiomyocytes by confocal microscopy. Results Expression of ROCK2 and expression and phosphorylation of PKCβ2 were increased in diabetic hearts. A physical interaction between the two kinases was demonstrated by reciprocal immunoprecipitation, while ROCK2 directly phosphorylated PKCβ2 at T641 in vitro. ROCK2 siRNA in vascular smooth muscle cells or inhibition of ROCK in diabetic hearts reduced PKCβ2 T641 phosphorylation, and this was associated with attenuation of PKCβ2 activity. PKCβ2 also formed a complex with PDK-1 and its target AKT, and ROCK inhibition resulted in upregulation of the phosphorylation of PDK-1 and AKT, and increased translocation of glucose transporter 4 (GLUT4) to the plasma membrane in diabetic hearts. Conclusion This study demonstrates that over-activation of ROCK2 contributes to diabetic cardiomyopathy by multiple mechanisms, including direct phosphorylation and activation of PKCβ2 and interference with the PDK-1-mediated phosphorylation and activation of AKT and translocation of GLUT4. This suggests that ROCK2 is a critical node in the development of diabetic cardiomyopathy and may be an effective target to improve cardiac function in diabetes.
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Affiliation(s)
- Guorong Lin
- Molecular and Cellular Pharmacology Research Group, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Roger W. Brownsey
- Dept. of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Kathleen M. MacLeod
- Molecular and Cellular Pharmacology Research Group, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
- * E-mail:
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Bhavanasi D, Kostyak JC, Swindle J, Kilpatrick LE, Kunapuli SP. CGX1037 is a novel PKC isoform delta selective inhibitor in platelets. Platelets 2014; 26:2-9. [PMID: 24433221 DOI: 10.3109/09537104.2013.868877] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Platelets upon activation change their shape, aggregate and secrete alpha and dense granule contents among which ADP acts as a feedback activator. Different Protein Kinase C (PKC) isoforms have specific non-redundant roles in mediating platelet responses including secretion and thrombus formation. Murine platelets lacking specific PKC isoforms have been used to evaluate the isoform specific functions. Novel PKC isoform δ has been shown to play an important role in some pathological processes. Lack of specific inhibitors for PKCδ has restricted analysis of its role in various cells. The current study was carried out to evaluate a novel small molecule PKCδ inhibitor, CGX1037 in platelets. Platelet aggregation, dense granule secretion and western blotting experiments were performed to evaluate CGX1037. In human platelets, CGX1037 inhibited PAR4-mediated phosphorylation on PKD2, a PKCδ-specific substrate. Pre-treatment of human or murine platelets with CGX1037 inhibited PAR4-mediated dense granule secretion whereas it potentiated GPVI-mediated dense granule secretion similar to the responses observed in murine platelets lacking PKCδ· Furthermore, pre-treatment of platelets from PKCδ(-/-) mice with CGX1037 had no significant additive effect on platelet responses suggesting the specificity of CGX1037. Hence, we show that CGX1037 is a selective small molecule inhibitor of PKCδ in platelets.
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Affiliation(s)
- Dheeraj Bhavanasi
- Department of Physiology, Temple University School of Medicine , Philadelphia, PA , USA
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Menard C, Bastianetto S, Quirion R. Neuroprotective effects of resveratrol and epigallocatechin gallate polyphenols are mediated by the activation of protein kinase C gamma. Front Cell Neurosci 2013; 7:281. [PMID: 24421757 PMCID: PMC3872731 DOI: 10.3389/fncel.2013.00281] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/15/2013] [Indexed: 01/08/2023] Open
Abstract
Polyphenols such as epigallocatechin gallate (EGCG) and resveratrol have received a great deal of attention because they may contribute to the purported neuroprotective action of the regular consumption of green tea and red wine. Many studies, including those published by our group, suggest that this protective action includes their abilities to prevent the neurotoxic effects of beta-amyloid, a protein whose accumulation likely plays a pivotal role in Alzheimer's disease. Moreover, the scavenging activities of polyphenols on reactive oxygen species and their inhibitory action of cyclooxygenase likely explain, at least in part, their antioxidant and anti-inflammatory activities. Besides these well-documented properties, the modulatory action of these polyphenols on intracellular signaling pathways related to cell death/survival (e.g., protein kinase C, PKC) has yet to be investigated in detail. Using rat hippocampal neuronal cells, we aimed to investigate here the effects of EGCG and resveratrol on cell death induced by GF 109203X, a selective inhibitor of PKC. The MTT/resazurin and spectrin assays indicated that EGCG and resveratrol protected against GF 109203X-induced cell death and cytoskeleton degeneration, with a maximal effect at 1 and 3 μM, respectively. Moreover, immunofluorescence data revealed that cells treated with these polyphenols increased PKC gamma (γ) activation and promoted neuronal interconnections. Finally, we found that the protective effects of both polyphenols on the cytoskeleton and synaptic plasticity were mediated by the PKCγ subunit. Taken together, the results suggest that PKC, and more specifically its γ subunit, plays a critical role in the protective action of EGCG and resveratrol on neuronal integrity.
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Affiliation(s)
- Caroline Menard
- Laboratory of Neuroendocrinology of Aging, Centre Hospitalier de l'Université de Montréal Research Center Montreal, QC, Canada ; Department of Medicine, University of Montreal Montreal, QC, Canada ; Douglas Mental Health University Institute, McGill University Montreal, QC, Canada ; Department of Psychiatry, McGill University Montreal, QC, Canada
| | - Stéphane Bastianetto
- Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
| | - Rémi Quirion
- Douglas Mental Health University Institute, McGill University Montreal, QC, Canada ; Department of Psychiatry, McGill University Montreal, QC, Canada
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Purinergic stimulation of K+-dependent Na+/Ca2+ exchanger isoform 4 requires dual activation by PKC and CaMKII. Biosci Rep 2013; 33:BSR20130099. [PMID: 24224486 PMCID: PMC3867797 DOI: 10.1042/bsr20130099] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
K+-dependent Na+/Ca2+-exchanger isoform 4 (NCXK4) is one of the most broadly expressed members of the NCKX (K+-dependent Na+/Ca2+-exchanger) family. Recent data indicate that NCKX4 plays a critical role in controlling normal Ca2+ signal dynamics in olfactory and other neurons. Synaptic Ca2+ dynamics are modulated by purinergic regulation, mediated by ATP released from synaptic vesicles or from neighbouring glial cells. Previous studies have focused on modulation of Ca2+ entry pathways that initiate signalling. Here we have investigated purinergic regulation of NCKX4, a powerful extrusion pathway that assists in terminating Ca2+ signals. NCKX4 activity was stimulated by ATP through activation of the P2Y receptor signalling pathway. Stimulation required dual activation of PKC (protein kinase C) and CaMKII (Ca2+/calmodulin-dependent protein kinase II). Mutating T312, a putative PKC phosphorylation site on NCKX4, partially prevented purinergic stimulation. These data illustrate how purinergic regulation can shape the dynamics of Ca2+ signalling by activating a signal damping and termination pathway. Activity of the K+-dependent Na+/Ca2+-exchanger, NCKX4, is stimulated by purinergic signals that depend on dual activation of two protein kinase pathways. This regulation provides a novel mechanism to shape Ca2+ signaling and thus to have important impact on neuronal processes.
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Khalil RA. Protein Kinase C Inhibitors as Modulators of Vascular Function and their Application in Vascular Disease. Pharmaceuticals (Basel) 2013; 6:407-39. [PMID: 23580870 PMCID: PMC3619439 DOI: 10.3390/ph6030407] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Blood pressure (BP) is regulated by multiple neuronal, hormonal, renal and vascular control mechanisms. Changes in signaling mechanisms in the endothelium, vascular smooth muscle (VSM) and extracellular matrix cause alterations in vascular tone and blood vessel remodeling and may lead to persistent increases in vascular resistance and hypertension (HTN). In VSM, activation of surface receptors by vasoconstrictor stimuli causes an increase in intracellular free Ca(2+) concentration ([Ca(2+)]i), which forms a complex with calmodulin, activates myosin light chain (MLC) kinase and leads to MLC phosphorylation, actin-myosin interaction and VSM contraction. Vasoconstrictor agonists could also increase the production of diacylglycerol which activates protein kinase C (PKC). PKC is a family of Ca(2+)-dependent and Ca(2+)-independent isozymes that have different distributions in various blood vessels, and undergo translocation from the cytosol to the plasma membrane, cytoskeleton or the nucleus during cell activation. In VSM, PKC translocation to the cell surface may trigger a cascade of biochemical events leading to activation of mitogen-activated protein kinase (MAPK) and MAPK kinase (MEK), a pathway that ultimately increases the myofilament force sensitivity to [Ca(2+)]i, and enhances actin-myosin interaction and VSM contraction. PKC translocation to the nucleus may induce transactivation of various genes and promote VSM growth and proliferation. PKC could also affect endothelium-derived relaxing and contracting factors as well as matrix metalloproteinase (MMPs) in the extracellular matrix further affecting vascular reactivity and remodeling. In addition to vasoactive factors, reactive oxygen species, inflammatory cytokines and other metabolic factors could affect PKC activity. Increased PKC expression and activity have been observed in vascular disease and in certain forms of experimental and human HTN. Targeting of vascular PKC using PKC inhibitors may function in concert with antioxidants, MMP inhibitors and cytokine antagonists to reduce VSM hyperactivity in certain forms of HTN that do not respond to Ca(2+) channel blockers.
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Affiliation(s)
- Raouf A Khalil
- Vascular Surgery Research Laboratory, Division of Vascular Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, 75 Francis Street; 02115, Massachusetts, USA
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Wheeler ML, Dong MB, Brink R, Zhong XP, DeFranco AL. Diacylglycerol kinase ζ limits B cell antigen receptor-dependent activation of ERK signaling to inhibit early antibody responses. Sci Signal 2013; 6:ra91. [PMID: 24129701 DOI: 10.1126/scisignal.2004189] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Signaling downstream of the B cell antigen receptor (BCR) is tightly regulated to enable cells to gauge the strength and duration of antigen-receptor interactions and to respond appropriately. We investigated whether metabolism of the second messenger diacylglycerol (DAG) by members of the family of DAG kinases (DGKs) played a role in modulating the magnitude of signaling by DAG downstream of the BCR. In the absence of DGKζ, the threshold for BCR signaling, measured as activation of the Ras-extracellular signal-regulated kinase (ERK) pathway, was markedly reduced in mature follicular B cells, which resulted in enhanced responses to antigen in vitro and in vivo. Inhibition of DAG signaling by DGKζ limited the number of antibody-secreting cells that were generated early in response to T cell-independent type 2 antigens, as well as to T cell-dependent antigens. Furthermore, the effect of loss of DGKζ closely resembled the effect of increasing the affinity of the BCR for antigen during the T cell-dependent antibody response. These results suggest that the magnitude of DAG signaling is important for translating the affinity of the BCR for antigen into the amount of antibody produced during the early stages of an immune response.
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Affiliation(s)
- Matthew L Wheeler
- 1Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
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Pakpour N, Camp L, Smithers HM, Wang B, Tu Z, Nadler SA, Luckhart S. Protein kinase C-dependent signaling controls the midgut epithelial barrier to malaria parasite infection in anopheline mosquitoes. PLoS One 2013; 8:e76535. [PMID: 24146884 PMCID: PMC3795702 DOI: 10.1371/journal.pone.0076535] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 09/01/2013] [Indexed: 11/19/2022] Open
Abstract
Anopheline mosquitoes are the primary vectors of parasites in the genus Plasmodium, the causative agents of malaria. Malaria parasites undergo a series of complex transformations upon ingestion by the mosquito host. During this process, the physical barrier of the midgut epithelium, along with innate immune defenses, functionally restrict parasite development. Although these defenses have been studied for some time, the regulatory factors that control them are poorly understood. The protein kinase C (PKC) gene family consists of serine/threonine kinases that serve as central signaling molecules and regulators of a broad spectrum of cellular processes including epithelial barrier function and immunity. Indeed, PKCs are highly conserved, ranging from 7 isoforms in Drosophila to 16 isoforms in mammals, yet none have been identified in mosquitoes. Despite conservation of the PKC gene family and their potential as targets for transmission-blocking strategies for malaria, no direct connections between PKCs, the mosquito immune response or epithelial barrier integrity are known. Here, we identify and characterize six PKC gene family members--PKCδ, PKCε, PKCζ, PKD, PKN, and an indeterminate conventional PKC--in Anopheles gambiae and Anopheles stephensi. Sequence and phylogenetic analyses of the anopheline PKCs support most subfamily assignments. All six PKCs are expressed in the midgut epithelia of A. gambiae and A. stephensi post-blood feeding, indicating availability for signaling in a tissue that is critical for malaria parasite development. Although inhibition of PKC enzymatic activity decreased NF-κB-regulated anti-microbial peptide expression in mosquito cells in vitro, PKC inhibition had no effect on expression of a panel of immune genes in the midgut epithelium in vivo. PKC inhibition did, however, significantly increase midgut barrier integrity and decrease development of P. falciparum oocysts in A. stephensi, suggesting that PKC-dependent signaling is a negative regulator of epithelial barrier function and a potential new target for transmission-blocking strategies.
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Affiliation(s)
- Nazzy Pakpour
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Lauren Camp
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Hannah M. Smithers
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Bo Wang
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Zhijian Tu
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Steven A. Nadler
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Shirley Luckhart
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, California, United States of America
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Xiao H, Liu M. Atypical protein kinase C in cell motility. Cell Mol Life Sci 2013; 70:3057-66. [PMID: 23096778 PMCID: PMC11113714 DOI: 10.1007/s00018-012-1192-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 09/03/2012] [Accepted: 10/08/2012] [Indexed: 01/01/2023]
Abstract
Cell motility is defined as cell movement in the three-dimensional space leading to repositioning of the cell. Atypical protein kinase C (aPKC, including ζ and λ/ι) are a subfamily of PKC. Different from classic PKC and novel PKC, the activation of atypical PKC is not dependent on diacylglycerol or calcium. PKCζ can be activated by lipid components, such as phosphatidylinositols, phosphatidic acid, arachidonic acid, and ceramide. Both phosphatidylinositol (3,4,5)-trisphosphate and PDK1 are necessary for the complete and stable activation of PKCζ. Atypical PKC is involved in the regulation of cell polarization, directional sensing, formation of filopodia, and cell motility. It is essential for migration and invasion of multiple cancer cell types. Particularly, atypical PKC has been found in the regulation of the motility of hematopoietic cells. It also participates in the regulation of proteolytic activity of podosomes and invadopodia. It has been found that atypical PKC can work coordinately with other PKC subfamily members and other signaling pathways. Research on the roles of atypical PKC in cell motility may lead to new therapeutic strategies for cancer and other diseases.
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Affiliation(s)
- Helan Xiao
- Latner Thoracic Surgery Research Laboratories, Toronto General Research Institute, University Health Network, Toronto, ON, Canada.
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Dong WH, Chen JC, He YL, Xu JJ, Mei YA. Resveratrol inhibits Kv2.2 currents through the estrogen receptor GPR30-mediated PKC pathway. Am J Physiol Cell Physiol 2013; 305:C547-57. [DOI: 10.1152/ajpcell.00146.2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Resveratrol (REV) is a naturally occurring phytoalexin that inhibits neuronal K+ channels; however, the molecular mechanisms behind the effects of REV and the relevant α-subunit are not well defined. With the use of patch-clamp technique, cultured cerebellar granule cells, and HEK-293 cells transfected with the Kv2.1 and Kv2.2 α-subunits, we investigated the effect of REV on Kv2.1 and Kv2.2 α-subunits. Our data demonstrated that REV significantly suppressed Kv2.2 but not Kv2.1 currents with a fast, reversible, and mildly concentration-dependent manner and shifted the activation or inactivation curve of Kv2.2 channels. Activating or inhibiting the cAMP/PKA pathway did not abolish the inhibition of Kv2.2 current by REV. In contrast, activation of PKC with phorbol 12-myristate 13-acetate mimicked the inhibitory effect of REV on Kv2.2 by modifying the activation or inactivation properties of Kv2.2 channels and eliminated any further inhibition by REV. PKC and PKC-α inhibitor completely eliminated the REV-induced inhibition of Kv2.2. Moreover, the effect of REV on Kv2.2 was reduced by preincubation with antagonists of GPR30 receptor and shRNA for GPR30 receptor. Western blotting results indicated that the levels of PKC-α and PKC-β were significantly increased in response to REV application. Our data reveal, for the first time, that REV inhibited Kv2.2 currents through PKC-dependent pathways and a nongenomic action of the oestrogen receptor GPR30.
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Affiliation(s)
- Wen-Hao Dong
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Jia-Chen Chen
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Yan-Lin He
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Jia-Jie Xu
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Yan-Ai Mei
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
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Differential regulation of cysteinyl leukotriene receptor signaling by protein kinase C in human mast cells. PLoS One 2013; 8:e71536. [PMID: 23977066 PMCID: PMC3744564 DOI: 10.1371/journal.pone.0071536] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/28/2013] [Indexed: 01/05/2023] Open
Abstract
Cysteinyl leukotrienes (cys-LTs) are a group of lipid mediators that are potent bronchoconstrictors, powerful inducers of vascular leakage and potentiators of airway hyperresponsiveness. Cys-LTs play an essential role in asthma and are synthesized as well as activated in mast cells (MCs). Cys-LTs relay their effects mainly through two known GPCRs, CysLT1R and CysLT2R. Although protein kinase C (PKC) isoforms are implicated in the regulation of CysLT1R function, neither the role of PKCs in cys-LT-dependent MC inflammatory signaling nor the involvement of specific isoforms in MC function are known. Here, we show that PKC inhibition augmented LTD4 and LTE4-induced calcium influx through CysLT1R in MCs. In contrast, inhibition of PKCs suppressed c-fos expression as well MIP1β generation by cys-LTs. Interestingly, cys-LTs activated both PKCα and PKCε isoforms in MC. However, knockdown of PKCα augmented cys-LT mediated calcium flux, while knockdown of PKCε attenuated cys-LT induced c-fos expression and MIP1β generation. Taken together, these results demonstrate for the first time that cys-LT signaling downstream of CysLT1R in MCs is differentially regulated by two distinct PKCs which modulate inflammatory signals that have significant pathobiologic implications in allergic reactions and asthma pathology.
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Garg R, Caino MC, Kazanietz MG. Regulation of Transcriptional Networks by PKC Isozymes: Identification of c-Rel as a Key Transcription Factor for PKC-Regulated Genes. PLoS One 2013; 8:e67319. [PMID: 23826267 PMCID: PMC3694964 DOI: 10.1371/journal.pone.0067319] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/16/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Activation of protein kinase C (PKC), a family of serine-threonine kinases widely implicated in cancer progression, has major impact on gene expression. In a recent genome-wide analysis of prostate cancer cells we identified distinctive gene expression profiles controlled by individual PKC isozymes and highlighted a prominent role for PKCδ in transcriptional activation. PRINCIPAL FINDINGS Here we carried out a thorough bioinformatics analysis to dissect transcriptional networks controlled by PKCα, PKCδ, and PKCε, the main diacylglycerol/phorbol ester PKCs expressed in prostate cancer cells. Despite the remarkable differences in the patterns of transcriptional responsive elements (REs) regulated by each PKC, we found that c-Rel represents the most frequent RE in promoters regulated by all three PKCs. In addition, promoters of PKCδ-regulated genes were particularly enriched with REs for CREB, NF-E2, RREB, SRF, Oct-1, Evi-1, and NF-κB. Most notably, by using transcription factor-specific RNAi we were able to identify subsets of PKCδ-regulated genes modulated by c-Rel and CREB. Furthermore, PKCδ-regulated genes condensed under the c-Rel transcriptional regulation display significant functional interconnections with biological processes such as angiogenesis, inflammatory response, and cell motility. CONCLUSION/SIGNIFICANCE Our study identified candidate transcription factors in the promoters of PKC regulated genes, in particular c-Rel was found as a key transcription factor in the control of PKCδ-regulated genes. The deconvolution of PKC-regulated transcriptional networks and their nodes may greatly help in the identification of PKC effectors and have significant therapeutics implications.
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Affiliation(s)
- Rachana Garg
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - M. Cecilia Caino
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Marcelo G. Kazanietz
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- * E-mail:
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Kojima T, Yamaguchi H, Ito T, Kyuno D, Kono T, Konno T, Sawada N. Tight junctions in human pancreatic duct epithelial cells. Tissue Barriers 2013; 1:e24894. [PMID: 24665406 PMCID: PMC3805649 DOI: 10.4161/tisb.24894] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/28/2013] [Accepted: 05/01/2013] [Indexed: 12/13/2022] Open
Abstract
Tight junctions of the pancreatic duct are essential regulators of physiologic secretion of the pancreas and disruption of the pancreatic ductal barrier is known to contribute to the pathogenesis of pancreatitis and progression of pancreatic cancer. Various inflammatory mediators and carcinogens can trigger tight junction disassembly and disruption of the pancreatic barrier, however signaling events that mediates such barrier dysfunctions remain poorly understood. This review focuses on structure and regulation of tight junctions in normal pancreatic epithelial cells and mechanisms of junctional disruption during pancreatic inflammation and cancer. We will pay special attention to a novel model of human telomerase reverse transcriptase-transfected human pancreatic ductal epithelial cells and will describe the roles of major signaling molecules such as protein kinase C and c-Jun N-terminal kinase in formation and disassembly of the pancreatic ductal barrier.
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Affiliation(s)
- Takashi Kojima
- Department of Pathology; Sapporo Medical University School of Medicine; Sapporo, Japan ; Department of Cell Science; Research Institute of Frontier Medicine; Sapporo Medical University School of Medicine; Sapporo, Japan
| | - Hiroshi Yamaguchi
- Department of Surgery; Sapporo Medical University School of Medicine; Sapporo, Japan
| | - Tatsuya Ito
- Department of Surgery; Sapporo Medical University School of Medicine; Sapporo, Japan
| | - Daisuke Kyuno
- Department of Surgery; Sapporo Medical University School of Medicine; Sapporo, Japan
| | - Tsuyoshi Kono
- Department of Pathology; Sapporo Medical University School of Medicine; Sapporo, Japan ; Department of Surgery; Sapporo Medical University School of Medicine; Sapporo, Japan
| | - Takumi Konno
- Department of Pathology; Sapporo Medical University School of Medicine; Sapporo, Japan ; Department of Cell Science; Research Institute of Frontier Medicine; Sapporo Medical University School of Medicine; Sapporo, Japan
| | - Norimasa Sawada
- Department of Pathology; Sapporo Medical University School of Medicine; Sapporo, Japan
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Wood TR, Chow RY, Hanes CM, Zhang X, Kashiwagi K, Shirai Y, Trebak M, Loegering DJ, Saito N, Lennartz MR. PKC-ε pseudosubstrate and catalytic activity are necessary for membrane delivery during IgG-mediated phagocytosis. J Leukoc Biol 2013; 94:109-22. [PMID: 23670290 DOI: 10.1189/jlb.1212634] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In RAW 264.7 cells, PKC-ε regulates FcγR-mediated phagocytosis. BMDM behave similarly; PKC-ε concentrates at phagosomes and internalization are reduced in PKC-ε⁻/⁻ cells. Two questions were asked: what is the role of PKC-ε? and what domains are necessary for PKC-ε concentration? Function was studied using BMDM and frustrated phagocytosis. On IgG surfaces, PKC-ε⁻/⁻ macrophages spread less than WT. Patch-clamping revealed that the spreading defect is a result of the failure of PKC-ε⁻/⁻ macrophages to add membrane. The defect is specific for FcγR ligation and can be reversed by expression of full-length (but not the isolated RD) PKC-ε in PKC-ε⁻/⁻ BMDM. Thus, PKC-ε function in phagocytosis requires translocation to phagosomes and the catalytic domain. The expression of chimeric PKC molecules in RAW cells identified the εPS as necessary for PKC-ε targeting. When placed into (nonlocalizing) PKC-δ, εPS was sufficient for concentration, albeit to a lesser degree than intact PKC-ε. In contrast, translocation of δ(εPSC1B) resembled that of WT PKC-ε. Thus, εPS and εC1B cooperate for optimal phagosome targeting. Finally, cells expressing εK437W were significantly less phagocytic than their PKC-ε-expressing counterparts, blocked at the pseudopod-extension phase. In summary, we have shown that εPS and εC1B are necessary and sufficient for targeting PKC-ε to phagosomes, where its catalytic activity is required for membrane delivery and pseudopod extension.
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Affiliation(s)
- Tiffany R Wood
- Centers for Cell Biology and Cancer Researchnces, Albany Medical College, Albany, New York, USA
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80
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Santinha DR, Luísa Dória M, Neves BM, Maciel EA, Martins J, Helguero L, Domingues P, Teresa Cruz M, Rosário Domingues M. Prospective phospholipid markers for skin sensitization prediction in keratinocytes: A phospholipidomic approach. Arch Biochem Biophys 2013; 533:33-41. [DOI: 10.1016/j.abb.2013.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 01/28/2013] [Accepted: 02/20/2013] [Indexed: 11/27/2022]
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81
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Mace OJ, Marshall F. DIGESTIVE PHYSIOLOGY OF THE PIG SYMPOSIUM: Gut chemosensing and the regulation of nutrient absorption and energy supply1. J Anim Sci 2013; 91:1932-45. [DOI: 10.2527/jas.2012-5906] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- O. J. Mace
- Heptares Therapeutics, BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
| | - F. Marshall
- Heptares Therapeutics, BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
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82
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Bonilla L, O‘Donnell V, Clark S, Rubbo H, Trostchansky A. Regulation of protein kinase C by nitroarachidonic acid: Impact on human platelet activation. Arch Biochem Biophys 2013; 533:55-61. [DOI: 10.1016/j.abb.2013.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/28/2013] [Accepted: 03/02/2013] [Indexed: 11/17/2022]
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83
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Sviridonov L, Dobkin-Bekman M, Shterntal B, Przedecki F, Formishell L, Kravchook S, Rahamim-Ben Navi L, Bar-Lev TH, Kazanietz MG, Yao Z, Seger R, Naor Z. Differential signaling of the GnRH receptor in pituitary gonadotrope cell lines and prostate cancer cell lines. Mol Cell Endocrinol 2013; 369:107-18. [PMID: 23380421 PMCID: PMC4100609 DOI: 10.1016/j.mce.2013.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/09/2013] [Accepted: 01/14/2013] [Indexed: 10/27/2022]
Abstract
The GnRH receptor (GnRHR) mediates the pituitary functions of GnRH, as well as its anti-proliferative effects in sex hormone-dependent cancer cells. Here we compare the signaling of GnRHR in pituitary gonadotrope cell lines vs. prostate cancer cell lines. We first noticed that the expression level of PKCα, PKCβII and PKCε is much higher in αT3-1 and LβT2 gonadotrope cell lines vs. LNCaP and DU-145 cell lines, while the opposite is seen for PKCδ. Activation of PKCα, PKCβII and PKCε by GnRH is relatively transient in αT3-1 and LβT2 gonadotrope cell lines and more prolonged in LNCaP and DU-145 cell lines. On the otherhand, the activation and re-distribution of the above PKCs by PMA was similar for both gonadotrope cell lines and prostate cancer cell lines. Activation of ERK1/2 by GnRH and PMA was robust in the gonadotrope cell lines, with a smaller effect observed in the prostate cancer cell lines. The Ca(2+) ionophore A23187 stimulated ERK1/2 in gonadotrope cell lines but not in prostate cancer cell lines. GnRH, PMA and A23187 stimulated JNK activity in gonadotrope cell lines, with a more sustained effect in prostate cancer cell lines. Sustained activation of p38 was observed for PMA and A23187 in Du-145 cells, while p38 activation by GnRH, PMA and A23187 in LβT2 cells was transient. Thus, differential expression and re-distribution of PKCs by GnRH and the transient vs. the more sustained nature of the activation of the PKC-MAPK cascade by GnRH in gonadotrope cell lines vs. prostate cancer cell lines respectively, may provide the mechanistic basis for the cell context-dependent differential biological responses observed in GnRH interaction with pituitary gonadotropes vs. prostate cancer cells.
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Affiliation(s)
- Ludmila Sviridonov
- Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
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84
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Tsai CM, Yen GC, Sun FM, Yang SF, Weng CJ. Assessment of the Anti-invasion Potential and Mechanism of Select Cinnamic Acid Derivatives on Human Lung Adenocarcinoma Cells. Mol Pharm 2013; 10:1890-900. [DOI: 10.1021/mp3006648] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Chiung-Man Tsai
- Institute of Medicine, Chung Shan Medical University, No. 110, Sec.1, Jianguo
N. Rd., Taichung 40256, Taiwan
- Department of Health, Tainan Hospital,
Executive Yuan, No. 125, Zhongshan
Rd., Tainan City 70043, Taiwan
| | - Gow-Chin Yen
- Department of Food Science and
Biotechnology, National Chung Hsing University, 250 Kuokuang Road, Taichung 40227, Taiwan
| | - Fang-Ming Sun
- Department of Health and Nutrition, ChiaNai University of Pharmacy and Science, 60, Sec.
1, Erh-jen Rd., Jen-te District, Tainan City 71710, Taiwan
| | - Shun-Fa Yang
- Institute of Medicine, Chung Shan Medical University, No. 110, Sec.1, Jianguo
N. Rd., Taichung 40256, Taiwan
- Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Chia-Jui Weng
- Graduate Institute of Applied Living
Science, Tainan University of Technology, 529 Zhongzheng Road, Yongkang District, Tainan City 71002, Taiwan
- Research & Development Center of Environment and Life Science, Tainan University of Technology, 529 Zhongzheng Road, Yongkang District, Tainan City 71002, Taiwan
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85
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Kamo T, Handa T, Nakano M. Lateral pressure change on phase transitions of phosphatidylcholine/diolein mixed membranes. Colloids Surf B Biointerfaces 2013; 104:128-32. [DOI: 10.1016/j.colsurfb.2012.11.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 11/26/2012] [Indexed: 02/08/2023]
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86
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KIM JEONGMI, NOH EUNMI, KWON KANGBEOM, KIM JONGSUK, YOU YONGOUK, HWANG JINKI, HWANG BOMI, KIM MINSEUK, LEE SEUNGJIN, JUNG SUNGHOO, YOUN HYUNJO, CHUNG EUNYONG, LEE YOUNGRAE. Suppression of TPA-induced tumor cell invasion by sulfuretin via inhibition of NF-κB-dependent MMP-9 expression. Oncol Rep 2013; 29:1231-7. [DOI: 10.3892/or.2012.2218] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 11/26/2012] [Indexed: 11/06/2022] Open
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87
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Xu Y, Zou ST, Zhu R, Li W, Gu CW, Wei SH, Xie JM, Wu HR. Inhibition of proliferation of estrogen receptor‑positive MCF‑7 human breast cancer cells by tamoxifen through c‑Jun transcription factors. Mol Med Rep 2013; 7:1283-7. [PMID: 23404426 DOI: 10.3892/mmr.2013.1306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/21/2013] [Indexed: 11/06/2022] Open
Abstract
Activator of protein 1 (AP-1) is a heterodimeric transcription factor composed of various members of the Jun and Fos families and binds to DNA at specific AP-1 binding sites. AP-1 transcriptional activity is increased by phosphorylation at serine residues in the c‑Jun component of AP-1. In the present study, the proliferation of MCF-7 breast cancer cells was found to be suppressed by tamoxifen (TAM)-activated c-Jun through the protein kinase C (PKC) pathway. The molecular mechanism by which c‑Jun activation induces antiproliferative signals in estrogen receptor (ER)-positive MCF-7 human breast cancer cells remains unknown. TAM inhibited the proliferation of ER-positive MCF-7 human breast cancer cells and ER-negative MDA-MB-435 human breast cancer cells and 48 h incubation with 10 µM TAM led to inhibition of 80% of proliferation. In addition, no significant difference in c-Jun mRNA and protein levels was detected in MCF-7 and MDA-MB-435 cells stimulated by TAM for 48 h. TAM treatment of MCF-7 cells activated the transcriptional activity of AP-1, which responds specifically to phorbol ester. To determine the role of c-Jun in the antiproliferation of MCF-7 cells stimulated by TAM, the inhibition rates of MCF‑7 cells were correlated with c‑Jun expression and stimulation of TAM. Results showed that the inhibition rate of TAM-stimulated MCF-7 cells was positively regulated by overexpression of c-Jun and negatively regulated by underexpression of c-Jun. Overall, these results indicate that the TAM-stimulated antiproliferation of MCF-7 cells is positively regulated by c-Jun through activation of the PKC pathway.
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Affiliation(s)
- Yan Xu
- Department of General Surgery, Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R China
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88
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Kyuno D, Kojima T, Yamaguchi H, Ito T, Kimura Y, Imamura M, Takasawa A, Murata M, Tanaka S, Hirata K, Sawada N. Protein kinase Cα inhibitor protects against downregulation of claudin-1 during epithelial-mesenchymal transition of pancreatic cancer. Carcinogenesis 2013; 34:1232-43. [PMID: 23389293 DOI: 10.1093/carcin/bgt057] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Protein kinase Cα (PKCα) is highly expressed in pancreatic cancer. However, the effects of PKCα on Snail and claudin-1, which play crucial roles in epithelial cell polarity during epithelial-mesenchymal transition (EMT), remain unclear. In this study, we investigated the mechanisms of regulation of Snail and claudin-1 via a PKCα signal pathway during EMT in pancreatic cancer cells and in normal human pancreatic duct epithelial cells (HPDEs). By immunostaining, overexpression of PKCα and downregulation of claudin-1 were observed in poorly differentiated human pancreatic cancer tissues and the pancreatic cancer cell line PANC-1. Treatment with the PKCα inhibitor Gö6976 transcriptionally decreased Snail and increased claudin-1 in PANC-1 cells. The PKCα inhibitor prevented upregulation of Snail and downregulation of claudin-1 during EMT induced by transforming growth factor-β1 (TGF-β1) treatment and under hypoxia in PANC-1 cells. The effects of the PKCα inhibitor were in part regulated via an extracellular signal-regulated kinase (ERK) signaling pathway. The PKCα inhibitor also prevented downregulation of the barrier function and fence function during EMT in well-differentiated pancreatic cancer cell line HPAC. In normal HPDEs, the PKCα inhibitor transcriptionally induced not only claudin-1 but also claudin-4, -7 and occludin without a change of Snail. Treatment with the PKCα inhibitor in normal HPDEs prevented downregulation of claudin-1 and occludin by TGF-β1 treatment and enhanced upregulation of claudin-1, -4, -7 and occludin under hypoxia. These findings suggest that PKCα regulates claudin-1 via Snail- and mitogen-activated protein kinase/ERK-dependent pathways during EMT in pancreatic cancer. Thus, PKCα inhibitors may be potential therapeutic agents against the malignancy of human pancreatic cancer cells.
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Affiliation(s)
- Daisuke Kyuno
- Department of Surgery, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
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89
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Divya PS, Jain K, Sobhia ME. From peptides to peptidomimetics: rational design of potential PKC-β II inhibitors. Med Chem Res 2013. [DOI: 10.1007/s00044-012-0056-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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90
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Protein kinase C regulates human pluripotent stem cell self-renewal. PLoS One 2013; 8:e54122. [PMID: 23349801 PMCID: PMC3549959 DOI: 10.1371/journal.pone.0054122] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 12/10/2012] [Indexed: 12/26/2022] Open
Abstract
Background The self-renewal of human pluripotent stem (hPS) cells including embryonic stem and induced pluripotent stem cells have been reported to be supported by various signal pathways. Among them, fibroblast growth factor-2 (FGF-2) appears indispensable to maintain self-renewal of hPS cells. However, downstream signaling of FGF-2 has not yet been clearly understood in hPS cells. Methodology/Principal Findings In this study, we screened a kinase inhibitor library using a high-throughput alkaline phosphatase (ALP) activity-based assay in a minimal growth factor-defined medium to understand FGF-2-related molecular mechanisms regulating self-renewal of hPS cells. We found that in the presence of FGF-2, an inhibitor of protein kinase C (PKC), GF109203X (GFX), increased ALP activity. GFX inhibited FGF-2-induced phosphorylation of glycogen synthase kinase-3β (GSK-3β), suggesting that FGF-2 induced PKC and then PKC inhibited the activity of GSK-3β. Addition of activin A increased phosphorylation of GSK-3β and extracellular signal-regulated kinase-1/2 (ERK-1/2) synergistically with FGF-2 whereas activin A alone did not. GFX negated differentiation of hPS cells induced by the PKC activator, phorbol 12-myristate 13-acetate whereas Gö6976, a selective inhibitor of PKCα, β, and γ isoforms could not counteract the effect of PMA. Intriguingly, functional gene analysis by RNA interference revealed that the phosphorylation of GSK-3β was reduced by siRNA of PKCδ, PKCε, and ζ, the phosphorylation of ERK-1/2 was reduced by siRNA of PKCε and ζ, and the phosphorylation of AKT was reduced by PKCε in hPS cells. Conclusions/Significance Our study suggested complicated cross-talk in hPS cells that FGF-2 induced the phosphorylation of phosphatidylinositol-3 kinase (PI3K)/AKT, mitogen-activated protein kinase/ERK-1/2 kinase (MEK), PKC/ERK-1/2 kinase, and PKC/GSK-3β. Addition of GFX with a MEK inhibitor, U0126, in the presence of FGF-2 and activin A provided a long-term stable undifferentiated state of hPS cells even though hPS cells were dissociated into single cells for passage. This study untangles the cross-talk between molecular mechanisms regulating self-renewal and differentiation of hPS cells.
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91
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Gopalakrishna R, McNeill TH, Elhiani AA, Gundimeda U. Methods for studying oxidative regulation of protein kinase C. Methods Enzymol 2013; 528:79-98. [PMID: 23849860 DOI: 10.1016/b978-0-12-405881-1.00005-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The protein kinase C (PKC) family of isoenzymes may be a crucial player in transducing H2O2-induced signaling in a wide variety of physiological and pathophysiological processes. PKCs contain unique structural features that make them highly susceptible to oxidative modification. Depending on the site of oxidation and the extent to which it is modified, PKC can be either activated or inactivated by H2O2. The N-terminal regulatory domain contains zinc-binding, cysteine-rich motifs that are readily oxidized by H2O2. When oxidized, the autoinhibitory function of the regulatory domain is compromised, and as a result, PKC is activated in a lipid cofactor-independent manner. The C-terminal catalytic domain contains several reactive cysteine residues, which when oxidized with a higher concentration of H2O2 leads to an inactivation of PKC. Here, we describe the methods used to induce oxidative modification of purified PKC isoenzymes by H2O2 and the methods to assess the extent of this modification. Protocols are given for isolating oxidatively activated PKC isoenzymes from cells treated with H2O2. Furthermore, we describe the methods used to assess indirect regulation of PKC isoenzymes by determining their cytosol to membrane or mitochondrial translocation and tyrosine phosphorylation of PKCδ in response to sublethal levels of H2O2. Finally, as an example, we describe the methods used to demonstrate the role of H2O2-mediated cell signaling of PKCɛ in green tea polyphenol-induced preconditioning against neuronal cell death caused by oxygen-glucose deprivation and reoxygenation, an in vitro model for cerebral ischemic/reperfusion injury.
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Affiliation(s)
- Rayudu Gopalakrishna
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
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92
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Yan Zhang E, Kong KF, Altman A. The yin and yang of protein kinase C-theta (PKCθ): a novel drug target for selective immunosuppression. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 66:267-312. [PMID: 23433459 PMCID: PMC3903317 DOI: 10.1016/b978-0-12-404717-4.00006-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Protein kinase C-theta (PKCθ) is a protein kinase C (PKC) family member expressed predominantly in T lymphocytes, and extensive studies addressing its function have been conducted. PKCθ is the only T cell-expressed PKC that localizes selectively to the center of the immunological synapse (IS) following conventional T cell antigen stimulation, and this unique localization is essential for PKCθ-mediated downstream signaling. While playing a minor role in T cell development, early in vitro studies relying, among others, on the use of PKCθ-deficient (Prkcq(-/-)) T cells revealed that PKCθ is required for the activation and proliferation of mature T cells, reflecting its importance in activating the transcription factors nuclear factor kappa B, activator protein-1, and nuclear factor of activated T cells, as well as for the survival of activated T cells. Upon subsequent analysis of in vivo immune responses in Prkcq(-/-) mice, it became clear that PKCθ has a selective role in the immune system: it is required for experimental Th2- and Th17-mediated allergic and autoimmune diseases, respectively, and for alloimmune responses, but is dispensable for protective responses against pathogens and for graft-versus-leukemia responses. Surprisingly, PKCθ was recently found to be excluded from the IS of regulatory T cells and to negatively regulate their suppressive function. These attributes of PKCθ make it an attractive target for catalytic or allosteric inhibitors that are expected to selectively suppress harmful inflammatory and alloimmune responses without interfering with beneficial immunity to infections. Early progress in developing such drugs is being made, but additional studies on the role of PKCθ in the human immune system are urgently needed.
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Affiliation(s)
| | | | - Amnon Altman
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
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93
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Joo DJ, Fang YH, Huh KH, Kim MS, Suh H, Kim YS. Changes in Serum Cytokine Profile after AEB071 (Sotrastaurin) or Tacrolimus versus Their Combinations in Rat Heterotopic Cardiac Allografts. KOREAN JOURNAL OF TRANSPLANTATION 2012. [DOI: 10.4285/jkstn.2012.26.4.248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Dong Jin Joo
- The Research Institute for Transplantation,Yonsei University College of Medicine, Seoul, Korea
- Department of Transplantation Surgery, Yonsei University Health System, Seoul, Korea
| | - Yu Hui Fang
- The Research Institute for Transplantation,Yonsei University College of Medicine, Seoul, Korea
- Graduate Program of Nanoscience and Technology, Yonsei University Health System, Seoul, Korea
| | - Kyu Ha Huh
- The Research Institute for Transplantation,Yonsei University College of Medicine, Seoul, Korea
- Department of Transplantation Surgery, Yonsei University Health System, Seoul, Korea
| | - Myoung Soo Kim
- The Research Institute for Transplantation,Yonsei University College of Medicine, Seoul, Korea
- Department of Transplantation Surgery, Yonsei University Health System, Seoul, Korea
| | - Hwal Suh
- Graduate Program of Nanoscience and Technology, Yonsei University Health System, Seoul, Korea
| | - Yu Seun Kim
- The Research Institute for Transplantation,Yonsei University College of Medicine, Seoul, Korea
- Department of Transplantation Surgery, Yonsei University Health System, Seoul, Korea
- Graduate Program of Nanoscience and Technology, Yonsei University Health System, Seoul, Korea
- Yonsei University, BK for Medical Science, Yonsei University Health System, Seoul, Korea
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94
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PKCδ-mediated phosphorylation of BAG3 at Ser187 site induces epithelial−mesenchymal transition and enhances invasiveness in thyroid cancer FRO cells. Oncogene 2012; 32:4539-48. [DOI: 10.1038/onc.2012.466] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 07/27/2012] [Accepted: 08/19/2012] [Indexed: 11/08/2022]
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95
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Mandadi S, Armati PJ, Roufogalis BD. Protein kinase C modulation of thermo-sensitive transient receptor potential channels: Implications for pain signaling. J Nat Sci Biol Med 2012; 2:13-25. [PMID: 22470230 PMCID: PMC3312694 DOI: 10.4103/0976-9668.82311] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A variety of molecules are reported to be involved in chronic pain. This review outlines the specifics of protein kinase C (PKC), its isoforms and their role in modulating thermo-sensitive transient receptor potential (TRP) channels TRPV1-4, TRPM8, and TRPA1. Anatomically, PKC and thermo-sensitive TRPs are co-expressed in cell bodies of nociceptive dorsal root ganglion (DRG) neurons, which are used as physiological correlates of peripheral and central projections involved in pain transmission. In the past decade, modulation of painful heat-sensitive TRPV1 by PKC has received the most attention. Recently, PKC modulation of other newly discovered thermo-sensitive pain-mediating TRPs has come into focus. Such modulation may occur under conditions of chronic pain resulting from nerve damage or inflammation. Since thermo-TRPs are primary detectors of acute pain stimuli, their modulation by PKC can severely alter their function, resulting in chronic pain. Comprehensive knowledge of pain signaling involving interaction of specific isoforms of PKC with specific thermo-sensitive TRP channels is incomplete. Such information is necessary to dissect out modality specific mechanisms to better manage the complex polymodal nature of chronic pain. This review is an attempt to update the readers on current knowledge of PKC modulation of thermo-sensitive TRPs and highlight implications of such modulation for pain signaling
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Affiliation(s)
- Sravan Mandadi
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
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96
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Kim JM, Noh EM, Kwon KB, Kim JS, You YO, Hwang JK, Hwang BM, Kim BS, Lee SH, Lee SJ, Jung SH, Youn HJ, Lee YR. Curcumin suppresses the TPA-induced invasion through inhibition of PKCα-dependent MMP-expression in MCF-7 human breast cancer cells. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2012; 19:1085-1092. [PMID: 22921746 DOI: 10.1016/j.phymed.2012.07.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 05/16/2012] [Accepted: 07/06/2012] [Indexed: 06/01/2023]
Abstract
Curcumin (diferuloylmethane) is a polyphenol derived from the plant turmeric (Curcuma longa), which is commonly used as a spice. Although anti-carcinogenic, anti-oxidant, anti-inflammation, and anti-angiogenic properties have been reported, the effect of curcumin on breast cancer metastasis is unknown. Matrix metalloproteinase-9 (MMP-9) is a major component in cancer cell invasion. In this study, we investigated the inhibitory effect of curcumin on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MMP-9 expression and cell invasion and the molecular mechanisms involved in MCF-7 cells. Our results showed that curcumin inhibits TPA-induced MMP-9 expression and cell invasion through suppressing NF-κB and AP-1 activation. Also, curcumin strongly repressed the TPA-induced phosphorylation of p38 and JNK and inhibited TPA-induced translocation of PKCα from the cytosol to the membrane, but did not affect the translocation of PKCδ. These results indicate that curcumin-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of the PKCα, MAPK and NF-κB/AP-1 pathway in MCF-7 cells. Curcumin may have potential value in restricting breast cancer metastasis.
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Affiliation(s)
- Jeong-Mi Kim
- Department of Biochemistry, Institute of Medical Science, Chonbuk National University Medical School, Jeonju 560-182, South Korea
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97
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Wang C, Shang Y, Yu J, Zhang M. Substrate recognition mechanism of atypical protein kinase Cs revealed by the structure of PKCι in complex with a substrate peptide from Par-3. Structure 2012; 20:791-801. [PMID: 22579248 DOI: 10.1016/j.str.2012.02.022] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 02/24/2012] [Accepted: 02/27/2012] [Indexed: 01/24/2023]
Abstract
Protein kinase C (PKC) play critical roles in many cellular functions including differentiation, proliferation, growth, and survival. However, the molecular bases governing PKC's substrate recognitions remain poorly understood. Here we determined the structure of PKCι in complex with a peptide from Par-3 at 2.4 Å. PKCι in the complex adopts catalytically competent, closed conformation without phosphorylation of Thr402 in the activation loop. The Par-3 peptide binds to an elongated groove formed by the N- and C-lobes of the kinase domain. The PKCι/Par-3 complex structure, together with extensive biochemical studies, reveals a set of substrate recognition sites common to all PKC isozymes as well as a hydrophobic pocket unique to aPKC. A consensus aPKC's substrate recognition sequence pattern can be readily identified based on the complex structure. Finally, we demonstrate that the pseudosubstrate sequence of PKCι resembles its substrate sequence, directly binds to and inhibits the activity of the kinase.
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Affiliation(s)
- Chihao Wang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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98
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Arai F, Hiyama A, Sakai D, Yokoyama K, Mochida J. The expression and role of non-canonical (PKC) signaling in nucleus pulposus cell metabolism. J Orthop Res 2012; 30:1478-85. [PMID: 22389031 DOI: 10.1002/jor.22095] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 02/02/2012] [Indexed: 02/04/2023]
Abstract
Canonical Wnt/β-catenin (hereafter Wnt) signaling regulates the proliferation and differentiation of various cell types. However, the role of non-canonical signaling including protein kinase C (PKC) signaling has not been investigated in intervertebral disc (IVD) cells. The aim of this study was to elucidate whether the activation of PKC signaling act to modulate Wnt signaling in IVD cells. We performed several reporter assays, real-time reverse transcription polymerase chain reaction (RT-PCR), immunohistochemical and immunofluorescence analyses, and western blot analyses using rat nucleus pulposus (NP) cells. We also examined the cell proliferation and cell cycle distribution under phorbol 12-myristate 13-acetate (PMA) stimulation, a known activator of PKC signaling. We found that NP cells exhibited decreased β-catenin mRNA and protein levels upon stimulation with PMA. PMA treatment promoted proliferation and cell cycle progression in a time- and dose-dependent manner. In addition, activation of the PKC signaling also regulated the expression of aggrecan. Finally, activation by PMA induced the expression of several PKC isoforms in NP cells. It is concluded that activation of PKC signaling might lead to an increase in matrix synthesis and cell proliferation, thereby inhibiting IVD degeneration. Crosstalk in these signaling pathways plays an important role in the regulation of IVD homeostasis.
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Affiliation(s)
- Fumiyuki Arai
- Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
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Gundimeda U, McNeill TH, Elhiani AA, Schiffman JE, Hinton DR, Gopalakrishna R. Green tea polyphenols precondition against cell death induced by oxygen-glucose deprivation via stimulation of laminin receptor, generation of reactive oxygen species, and activation of protein kinase Cε. J Biol Chem 2012; 287:34694-708. [PMID: 22879598 DOI: 10.1074/jbc.m112.356899] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
As the development of synthetic drugs for the prevention of stroke has proven challenging, utilization of natural products capable of preconditioning neuronal cells against ischemia-induced cell death would be a highly useful complementary approach. In this study using an oxygen-glucose deprivation and reoxygenation (OGD/R) model in PC12 cells, we show that 2-day pretreatment with green tea polyphenols (GTPP) and their active ingredient, epigallocatechin-3-gallate (EGCG), protects cells from subsequent OGD/R-induced cell death. A synergistic interaction was observed between GTPP constituents, with unfractionated GTPP more potently preconditioning cells than EGCG. GTPP-induced preconditioning required the 67-kDa laminin receptor (67LR), to which EGCG binds with high affinity. 67LR also mediated the generation of reactive oxygen species (ROS) via activation of NADPH oxidase. An exogenous ROS-generating system bypassed 67LR to induce preconditioning, suggesting that sublethal levels of ROS are indeed an important mediator in GTPP-induced preconditioning. This role for ROS was further supported by the fact that antioxidants blocked GTPP-induced preconditioning. Additionally, ROS induced an activation and translocation of protein kinase C (PKC), particularly PKCε from the cytosol to the membrane/mitochondria, which was also blocked by antioxidants. The crucial role of PKC in GTPP-induced preconditioning was supported by use of its specific inhibitors. Preconditioning was increased by conditional overexpression of PKCε and decreased by its knock-out with siRNA. Collectively, these results suggest that GTPP stimulates 67LR and thereby induces NADPH oxidase-dependent generation of ROS, which in turn induces activation of PKC, particularly prosurvival isoenzyme PKCε, resulting in preconditioning against cell death induced by OGD/R.
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Affiliation(s)
- Usha Gundimeda
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089, USA
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Sun Z. Intervention of PKC-θ as an immunosuppressive regimen. Front Immunol 2012; 3:225. [PMID: 22876242 PMCID: PMC3410430 DOI: 10.3389/fimmu.2012.00225] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 07/10/2012] [Indexed: 01/04/2023] Open
Abstract
PKC-θ is selectively enriched in T cells and specifically translocates to immunological synapse where it mediates critical T cell receptor signals required for T cell activation, differentiation, and survival. T cells deficient in PKC-θ are defective in their ability to differentiate into inflammatory effector cells that mediate actual immune responses whereas, their differentiation into regulatory T cells (Treg) that inhibits the inflammatory T cells is enhanced. Therefore, the manipulation of PKC-θ activity can shift the ratio between inflammatory effector T cells and inhibitory Tregs, to control T cell-mediated immune responses that are responsible for autoimmunity and allograft rejection. Indeed, PKC-θ-deficient mice are resistant to the development of several Th2 and Th17-dependent autoimmune diseases and are defective in mounting alloimmune responses required for rejection of transplanted allografts and graft-versus-host disease. Selective inhibition of PKC-θ is therefore considered as a potential treatment for prevention of autoimmune diseases and allograft rejection.
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Affiliation(s)
- Zuoming Sun
- Division of Immunology, Beckman Research Institute of the City of Hope, Duarte, CA, USA
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