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IUBMB Life Jun 2019Protein kinase C (PKC) is activated by 1,2-diacylglycerol as a second messenger in the signaling mechanism coupled with the hydrolysis of membrane inositol... (Review)
Review
Protein kinase C (PKC) is activated by 1,2-diacylglycerol as a second messenger in the signaling mechanism coupled with the hydrolysis of membrane inositol phospholipids, although it was not found by screening for a 1,2-diacylglycerol-dependent enzyme. PKC is also a receptor for the tumor-promoting phorbol esters, but it was not identified by its property of binding phorbol esters, either. Instead, the discovery and characterization of PKC, now known to comprise a family with multiple isoforms, was through a circuitous voyage filled with unexpected twists and turns. This review summarizes the discovery and the initial experiments of PKC as a historical perspective of the enzyme family in the context of the progress in the studies on protein phosphorylation. © 2018 IUBMB Life, 71(6):697-705, 2019.
Topics: Diglycerides; Humans; Hydrolysis; Phorbol Esters; Phosphatidylinositols; Phosphorylation; Protein Binding; Protein Kinase C; Proteins
PubMed: 30393952
DOI: 10.1002/iub.1963 -
Journal of Medicinal Chemistry Feb 2022Three new diterpenes, stellejasmins A () and B () and 12--benzoylphorbol-13-heptanoate (), were isolated from the roots of L. The structures of - were elucidated by...
Three new diterpenes, stellejasmins A () and B () and 12--benzoylphorbol-13-heptanoate (), were isolated from the roots of L. The structures of - were elucidated by extensive NMR and mass spectroscopic analyses. Compounds and are the first derivatives containing a hydroxy group at C-2 in the family of daphnane and tigliane diterpenes. The presence of a chlorine atom in is unique in the plant metabolite. Compound has an odd-number acyl group, which is biosynthetically notable. Human immunodeficiency virus (HIV) LTR-driven transcription activity was tested with - and 17 known diterpenes isolated from L. and A.Gray. Among these, gnidimacrin (), stelleralide A (), and wikstroelide A () were highly potent, with EC values of 0.14, 0.33, and 0.39 nM, respectively. The structure-activity relationship (SAR) was investigated using 20 natural and eight synthetic diterpenes. This is the first SAR study on natural daphnane and tigliane diterpenes.
Topics: Anti-HIV Agents; Diterpenes; HIV; Models, Molecular; Molecular Docking Simulation; Phorbols; Plant Extracts; Plant Roots; Structure-Activity Relationship; Thymelaeaceae; Virus Latency; Wikstroemia
PubMed: 35113551
DOI: 10.1021/acs.jmedchem.1c01973 -
Molecular Systems Biology Mar 2017To monitor transcriptional regulation in human cells, rapid changes in enhancer and promoter activity must be captured with high sensitivity and temporal resolution....
To monitor transcriptional regulation in human cells, rapid changes in enhancer and promoter activity must be captured with high sensitivity and temporal resolution. Here, we show that the recently established protocol TT-seq ("transient transcriptome sequencing") can monitor rapid changes in transcription from enhancers and promoters during the immediate response of T cells to ionomycin and phorbol 12-myristate 13-acetate (PMA). TT-seq maps eRNAs and mRNAs every 5 min after T-cell stimulation with high sensitivity and identifies many new primary response genes. TT-seq reveals that the synthesis of 1,601 eRNAs and 650 mRNAs changes significantly within only 15 min after stimulation, when standard RNA-seq does not detect differentially expressed genes. Transcription of enhancers that are primed for activation by nucleosome depletion can occur immediately and simultaneously with transcription of target gene promoters. Our results indicate that enhancer transcription is a good proxy for enhancer regulatory activity in target gene activation, and establish TT-seq as a tool for monitoring the dynamics of enhancer landscapes and transcription programs during cellular responses and differentiation.
Topics: Base Pairing; Enhancer Elements, Genetic; Gene Expression Profiling; Gene Expression Regulation; Humans; Ionomycin; Jurkat Cells; RNA; Sequence Analysis, RNA; T-Lymphocytes; Tetradecanoylphorbol Acetate; Transcription, Genetic; Transcriptional Activation
PubMed: 28270558
DOI: 10.15252/msb.20167507 -
Chinese Journal of Natural Medicines Feb 2024In this study, 37 derivatives of phorbol esters were synthesized and their anti-HIV-1 activities evaluated, building upon our previous synthesis of 51 phorbol...
In this study, 37 derivatives of phorbol esters were synthesized and their anti-HIV-1 activities evaluated, building upon our previous synthesis of 51 phorbol derivatives. 12-Para-electron-acceptor-trans-cinnamoyl-13-decanoyl phorbol derivatives stood out, demonstrating remarkable anti-HIV-1 activities and inhibitory effects on syncytia formation. These derivatives exhibited a higher safety index compared with the positive control drug. Among them, 12-(trans-4-fluorocinnamoyl)-13-decanoyl phorbol, designated as compound 3c, exhibited the most potent anti-HIV-1 activity (EC 2.9 nmol·L, CC/EC 11 117.24) and significantly inhibited the formation of syncytium (EC 7.0 nmol·L, CC/EC 4891.43). Moreover, compound 3c is hypothesized to act both as an HIV-1 entry inhibitor and as an HIV-1 reverse transcriptase inhibitor. Isothermal titration calorimetry and molecular docking studies indicated that compound 3c may also function as a natural activator of protein kinase C (PKC). Therefore, compound 3c emerges as a potential candidate for developing new anti-HIV drugs.
Topics: Molecular Docking Simulation; Anti-HIV Agents; Phorbols; Phorbol Esters; HIV Reverse Transcriptase; Structure-Activity Relationship
PubMed: 38342567
DOI: 10.1016/S1875-5364(24)60587-X -
Chinese Journal of Natural Medicines Apr 2024Phorbol esters are recognized for their dual role as anti-HIV-1 agents and as activators of protein kinase C (PKC). The efficacy of phorbol esters in binding with PKC is...
Phorbol esters are recognized for their dual role as anti-HIV-1 agents and as activators of protein kinase C (PKC). The efficacy of phorbol esters in binding with PKC is attributed to the presence of oxygen groups at positions C20, C3/C4, and C9 of phorbol. Concurrently, the lipids located at positions C12/C13 are essential for both the anti-HIV-1 activity and the formation of the PKC-ligand complex. The influence of the cyclopropane ring at positions C13 and C14 in phorbol derivatives on their anti-HIV-1 activity requires further exploration. This research entailed the hydrolysis of phorbol, producing seco-cyclic phorbol derivatives. The anti-HIV-1 efficacy of these derivatives was assessed, and the affinity constant (K) for PKC-δ protein of selected seco-cyclic phorbol derivatives was determined through isothermal titration calorimetry. The findings suggest that the chemical modification of cyclopropanols could affect both the anti-HIV-1 activity and the PKC binding affinity. Remarkably, compound S11, with an EC50 of 0.27 μmol·L and a CC of 153.92 μmol·L, demonstrated a potent inhibitory effect on the intermediate products of HIV-1 reverse transcription (ssDNA and 2LTR), likely acting at the viral entry stage, yet showed no affinity for the PKC-δ protein. These results position compound S11 as a potential candidate for further preclinical investigation and for studies aimed at elucidating the pharmacological mechanism underlying its anti-HIV-1 activity.
Topics: HIV-1; Humans; Anti-HIV Agents; Phorbol Esters; Molecular Structure; Protein Kinase C; Structure-Activity Relationship
PubMed: 38658099
DOI: 10.1016/S1875-5364(24)60630-8 -
Biochemistry Jul 2019Bryostatin 1 is a natural macrolide shown to improve neuronal connections and enhance memory in mice. Its mechanism of action is largely attributed to the modulation of...
Bryostatin 1 is a natural macrolide shown to improve neuronal connections and enhance memory in mice. Its mechanism of action is largely attributed to the modulation of novel and conventional protein kinase Cs (PKCs) by binding to their regulatory C1 domains. Munc13-1 is a C1 domain-containing protein that shares common endogenous and exogenous activators with novel and conventional PKC subtypes. Given the essential role of Munc13-1 in the priming of synaptic vesicles and neuronal transmission overall, we explored the potential interaction between bryostatin 1 and Munc13-1. Our results indicate that in vitro bryostatin 1 binds to both the isolated C1 domain of Munc13-1 ( K = 8.07 ± 0.90 nM) and the full-length Munc13-1 protein ( K = 0.45 ± 0.04 nM). Furthermore, confocal microscopy and immunoblot analysis demonstrated that in intact HT22 cells bryostatin 1 mimics the actions of phorbol esters, a previously established class of Munc13-1 activators, and induces plasma membrane translocation of Munc13-1, a hallmark of its activation. Consistently, bryostatin 1 had no effect on the Munc13-1 construct that is insensitive to phorbol esters. Effects of bryostatin 1 on the other Munc13 family members, ubMunc13-2 and bMunc13-2, resembled those of Munc13-1 for translocation. Lastly, we observed an increased level of expression of Munc13-1 following a 24 h incubation with bryostatin 1 in both HT22 and primary mouse hippocampal cells. This study characterizes Munc13-1 as a molecular target of bryostatin 1. Considering the crucial role of Munc13-1 in neuronal function, these findings provide strong support for the potential role of Munc13s in the actions of bryostatin 1.
Topics: Animals; Binding Sites; Bryostatins; Cell Line; Cells, Cultured; Mice; Models, Molecular; Molecular Docking Simulation; Nerve Tissue Proteins; Neurons; Phorbol Esters; Protein Binding
PubMed: 31243993
DOI: 10.1021/acs.biochem.9b00427 -
Food and Chemical Toxicology : An... Jan 2022Pulmonary inflammation involves complex immune responses in which alveolar macrophages release pro-inflammatory proteins and cytokines. Cardamonin is a spice component...
Pulmonary inflammation involves complex immune responses in which alveolar macrophages release pro-inflammatory proteins and cytokines. Cardamonin is a spice component that exerts anti-inflammatory and anti-oxidative properties against pulmonary inflammation. Herein, the aim of this research is to investigate the effects of cardamonin on pulmonary inflammation and its mechanism. Pulmonary inflammation in mice was induced by intratracheal administration of PMA. PMA-stimulated acute fibrosis, pulmonary edema, and inflammatory responses were ameliorated by oral administration of cardamonin in vivo. In MH-S alveolar macrophages, PMA-induced pro-inflammatory responses, including iNOS, COX-2, MMP-9 and cytokines expressions were reduced by cardamonin. The anti-oxidative Nrf2/HO-1 axis was also provoked by cardamonin in MH-S alveolar macrophages. In addition, MMP-9 expression induced by PMA is also decreased by the down-stream metabolites of HO-1, indicating that HO-1 expression partially contributes to the anti-inflammatory effect exerted by cardamonin. In this study, cardamonin demonstrates anti-inflammatory and anti-oxidative effects on PMA-induced pulmonary inflammation and activating Nrf2/HO-1 axis in alveolar macrophages. Cardamonin also ameliorates pulmonary inflammation, rapid fibrosis in vivo, suggesting powerful health benefits.
Topics: Animals; Anti-Inflammatory Agents; Chalcones; Heme Oxygenase-1; Lung; Macrophages, Alveolar; Membrane Proteins; Mice; NF-E2-Related Factor 2; Pneumonia; Tetradecanoylphorbol Acetate
PubMed: 34890758
DOI: 10.1016/j.fct.2021.112761 -
Molecular Therapy : the Journal of the... Mar 2016Complete eradication of HIV-1 infection is impeded by the existence of cells that harbor chromosomally integrated but transcriptionally inactive provirus. These cells...
Complete eradication of HIV-1 infection is impeded by the existence of cells that harbor chromosomally integrated but transcriptionally inactive provirus. These cells can persist for years without producing viral progeny, rendering them refractory to immune surveillance and antiretroviral therapy and providing a permanent reservoir for the stochastic reactivation and reseeding of HIV-1. Strategies for purging this latent reservoir are thus needed to eradicate infection. Here, we show that engineered transcriptional activation systems based on CRISPR/Cas9 can be harnessed to activate viral gene expression in cell line models of HIV-1 latency. We further demonstrate that complementing Cas9 activators with latency-reversing compounds can enhance latent HIV-1 transcription and that epigenome modulation using CRISPR-based acetyltransferases can also promote viral gene activation. Collectively, these results demonstrate that CRISPR systems are potentially effective tools for inducing latent HIV-1 expression and that their use, in combination with antiretroviral therapy, could lead to improved therapies for HIV-1 infection.
Topics: CRISPR-Cas Systems; Cell Line; Clustered Regularly Interspaced Short Palindromic Repeats; Drug Synergism; Epigenesis, Genetic; Gene Editing; Gene Expression Regulation, Viral; HIV Infections; HIV Long Terminal Repeat; HIV-1; Histone Deacetylase Inhibitors; Humans; Phorbol Esters; Protein Binding; RNA, Guide, CRISPR-Cas Systems; Transcriptional Activation; Virus Activation; Virus Latency
PubMed: 26607397
DOI: 10.1038/mt.2015.213 -
The Biochemical Journal Aug 2022The protein kinases PAK4, PAK5 and PAK6 comprise a family of ohnologues. In multiple cancers including melanomas PAK5 most frequently carries non-synonymous mutations;...
The protein kinases PAK4, PAK5 and PAK6 comprise a family of ohnologues. In multiple cancers including melanomas PAK5 most frequently carries non-synonymous mutations; PAK6 and PAK4 have fewer; and PAK4 is often amplified. To help interpret these genomic data, initially we compared the cellular regulation of the sister kinases and their roles in melanoma cells. In common with many ohnologue protein kinases, PAK4, PAK5 and PAK6 each have two 14-3-3-binding phosphosites of which phosphoSer99 is conserved. PAK4 localises to the leading edge of cells in response to phorbol ester-stimulated binding of 14-3-3 to phosphoSer99 and phosphoSer181, which are phosphorylated by two different PKCs or PKDs. These phosphorylations of PAK4 are essential for its phorbol ester-stimulated phosphorylation of downstream substrates. In contrast, 14-3-3 interacts with PAK5 in response to phorbol ester-stimulated phosphorylation of Ser99 and epidermal growth factor-stimulated phosphorylation of Ser288; whereas PAK6 docks onto 14-3-3 and is prevented from localising to cell-cell junctions when Ser133 is phosphorylated in response to cAMP-elevating agents via PKA and insulin-like growth factor 1 via PKB/Akt. Silencing of PAK4 impairs viability, migration and invasive behaviour of melanoma cells carrying BRAFV600E or NRASQ61K mutations. These defects are rescued by ectopic expression of PAK4, more so by a 14-3-3-binding deficient PAK4, and barely by PAK5 or PAK6. Together these genomic, biochemical and cellular data suggest that the oncogenic properties of PAK4 are regulated by PKC-PKD signalling in melanoma, while PAK5 and PAK6 are dispensable in this cancer.
Topics: Humans; Melanoma; Phorbol Esters; Phosphorylation; Protein Kinases; p21-Activated Kinases
PubMed: 35969127
DOI: 10.1042/BCJ20220184 -
The AAPS Journal Nov 2022Overexposure to ultraviolet radiation and environmental carcinogens drive skin cancer development through redox imbalance and gene mutation. Antioxidants such as...
Overexposure to ultraviolet radiation and environmental carcinogens drive skin cancer development through redox imbalance and gene mutation. Antioxidants such as triterpenoids have exhibited anti-oxidative and anti-inflammatory potentials to alleviate skin carcinogenesis. This study investigated the methylome and transcriptome altered by tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) or TPA with 2-cyano 2,3-dioxoolean-1,9-dien-28-oic acid (CDDO). The results show that CDDO blocks TPA-induced transformation dose dependently. Several differential expressed genes (DEGs) involved in skin cell transformation, while counteracted by CDDO, were revealed by differential expression analysis including Lyl1, Lad1, and Dennd2d. In CpG methylomic profiles, the differentially methylated regions (DMRs) in the promoter region altered by TPA while showing the opposite methylation status in the CDDO treatment group were identified. The correlation between DNA methylation and RNA expression has been established and DMRs showing inverse correlation were further studied as potential therapeutic targets. From the CpG methylome and transcriptome results, CDDO significantly restored gene expression of NAD(P)H:quinone oxidoreductase 1 (Nqo1) inhibited by TPA by decreasing their promoter CpG methylation. Ingenuity Pathways Analysis (IPA) shows that CDDO neutralized the effect of TPA through modulating cell cycles, cell migration, and inflammatory and immune response regulatory pathways. Notably, Tumor Necrosis Factor Receptor 2 (TNFR2) signaling was significantly downregulated by CDDO potentially contributing to prevention of TPA-induced cell transformation. Overall, incorporating the transcriptome, CpG methylome, and signaling pathway network, we reveal potential therapeutic targets and pathways by which CDDO could reverse TPA-induced carcinogenesis. The results could be useful for future human study and targets development for skin cancer.
Topics: Humans; Epigenome; Tetradecanoylphorbol Acetate; Triterpenes; Transcriptome; Ultraviolet Rays; Cell Transformation, Neoplastic; Skin Neoplasms
PubMed: 36324037
DOI: 10.1208/s12248-022-00763-5