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Stanková J, Jurášek M, Hajdúch M, Džubák P. Terpenes and Terpenoids Conjugated with BODIPYs: An Overview of Biological and Chemical Properties. JOURNAL OF NATURAL PRODUCTS 2024; 87:1306-1319. [PMID: 38482846 PMCID: PMC11061839 DOI: 10.1021/acs.jnatprod.3c00961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 05/03/2024]
Abstract
Advancements in small-molecule research have created the need for sensitive techniques to accurately study biological processes in living systems. Fluorescent-labeled probes have become indispensable tools, particularly those that use boron-dipyrromethene (BODIPY) dyes. Terpenes and terpenoids are organic compounds found in nature that offer diverse biological activities, and BODIPY-based probes play a crucial role in studying these compounds. Monoterpene-BODIPY conjugates have exhibited potential for staining bacterial and fungal cells. Sesquiterpene-BODIPY derivatives have been used to study sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA), indicating their potential for drug development. Owing to their unique properties, diterpenes have been investigated using BODIPY conjugates to evaluate their mechanisms of action. Triterpene-BODIPY conjugates have been synthesized for biological studies, with different spacers affecting their cytotoxicity. Fluorescent probes, inspired by terpenoid-containing vitamins, have also been developed. Derivatives of tocopherol, coenzyme Q10, and vitamin K1 can provide insights into their oxidation-reduction abilities. All these probes have diverse applications, including the study of cell membranes to investigate immune responses and antioxidant properties. Further research in this field can help better understand and use terpenes and terpenoids in various biological contexts.
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Affiliation(s)
- Jarmila Stanková
- Institute
of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, 77900 Olomouc, Czech Republic
| | - Michal Jurášek
- Department
of Chemistry of Natural Compounds, University
of Chemistry and Technology Prague, 16628 Prague, Czech Republic
| | - Marián Hajdúch
- Institute
of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, 77900 Olomouc, Czech Republic
- Laboratory
of Experimental Medicine, Institute of Molecular and Translational
Medicine, University Hospital Olomouc, 77900 Olomouc, Czech Republic
| | - Petr Džubák
- Institute
of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, 77900 Olomouc, Czech Republic
- Laboratory
of Experimental Medicine, Institute of Molecular and Translational
Medicine, University Hospital Olomouc, 77900 Olomouc, Czech Republic
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Mbonye U, Karn J. The cell biology of HIV-1 latency and rebound. Retrovirology 2024; 21:6. [PMID: 38580979 PMCID: PMC10996279 DOI: 10.1186/s12977-024-00639-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024] Open
Abstract
Transcriptionally latent forms of replication-competent proviruses, present primarily in a small subset of memory CD4+ T cells, pose the primary barrier to a cure for HIV-1 infection because they are the source of the viral rebound that almost inevitably follows the interruption of antiretroviral therapy. Over the last 30 years, many of the factors essential for initiating HIV-1 transcription have been identified in studies performed using transformed cell lines, such as the Jurkat T-cell model. However, as highlighted in this review, several poorly understood mechanisms still need to be elucidated, including the molecular basis for promoter-proximal pausing of the transcribing complex and the detailed mechanism of the delivery of P-TEFb from 7SK snRNP. Furthermore, the central paradox of HIV-1 transcription remains unsolved: how are the initial rounds of transcription achieved in the absence of Tat? A critical limitation of the transformed cell models is that they do not recapitulate the transitions between active effector cells and quiescent memory T cells. Therefore, investigation of the molecular mechanisms of HIV-1 latency reversal and LRA efficacy in a proper physiological context requires the utilization of primary cell models. Recent mechanistic studies of HIV-1 transcription using latently infected cells recovered from donors and ex vivo cellular models of viral latency have demonstrated that the primary blocks to HIV-1 transcription in memory CD4+ T cells are restrictive epigenetic features at the proviral promoter, the cytoplasmic sequestration of key transcription initiation factors such as NFAT and NF-κB, and the vanishingly low expression of the cellular transcription elongation factor P-TEFb. One of the foremost schemes to eliminate the residual reservoir is to deliberately reactivate latent HIV-1 proviruses to enable clearance of persisting latently infected cells-the "Shock and Kill" strategy. For "Shock and Kill" to become efficient, effective, non-toxic latency-reversing agents (LRAs) must be discovered. Since multiple restrictions limit viral reactivation in primary cells, understanding the T-cell signaling mechanisms that are essential for stimulating P-TEFb biogenesis, initiation factor activation, and reversing the proviral epigenetic restrictions have become a prerequisite for the development of more effective LRAs.
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Affiliation(s)
- Uri Mbonye
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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3
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Reversible Platelet Integrin αIIbβ3 Activation and Thrombus Instability. Int J Mol Sci 2022; 23:ijms232012512. [PMID: 36293367 PMCID: PMC9604507 DOI: 10.3390/ijms232012512] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/28/2022] Open
Abstract
Integrin αIIbβ3 activation is essential for platelet aggregation and, accordingly, for hemostasis and arterial thrombosis. The αIIbβ3 integrin is highly expressed on platelets and requires an activation step for binding to fibrinogen, fibrin or von Willebrand factor (VWF). A current model assumes that the process of integrin activation relies on actomyosin force-dependent molecular changes from a bent-closed and extended-closed to an extended-open conformation. In this paper we review the pathways that point to a functional reversibility of platelet αIIbβ3 activation and transient aggregation. Furthermore, we refer to mouse models indicating that genetic defects that lead to reversible platelet aggregation can also cause instable thrombus formation. We discuss the platelet agonists and signaling pathways that lead to a transient binding of ligands to integrin αIIbβ3. Our analysis points to the (autocrine) ADP P2Y1 and P2Y12 receptor signaling via phosphoinositide 3-kinases and Akt as principal pathways linked to reversible integrin activation. Downstream signaling events by protein kinase C, CalDAG-GEFI and Rap1b have not been linked to transient integrin activation. Insight into the functional reversibility of integrin activation pathways will help to better understand the effects of antiplatelet agents.
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Liu Y, Tang W, Ao J, Zhang J, Feng L. Transcriptomics integrated with metabolomics reveals the effect of Bisphenol F (BPF) exposure on intestinal inflammation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 816:151644. [PMID: 34774955 DOI: 10.1016/j.scitotenv.2021.151644] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/16/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
As a viable alternative to Bisphenol A (BPA), Bisphenol F (BPF) has been detected in humans at comparable concentrations and detection frequencies. Emerging evidence reveals that BPF induces intestinal toxicity. However, less information is available concerning BPF and its potential effects on intestinal inflammation, which has been associated with numerous disorders. The results from the present study showed that BPF exposure triggered lipopolysaccharide (LPS)-induced explosion of pro-inflammatory cytokines interleukin-17A (IL-17A), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) and impairment of the intestinal epithelial barrier by downregulating the expression of tight junction proteins Zonula Occludens-1 (ZO-1) and Claudin-1 (CLDN1) in normal colonic epithelial cells (NCM460). A multi-omics analysis integrating the transcriptomics with metabolomics revealed an altered transcripts and metabolites profile following BPF exposure. Correlation analysis indicated that RAS Guanyl Releasing Protein 2 (RASGRP2) and Phospholipase A2 Group IVE (PLA2G4E) were positively associated with the increased serotonin which was positively associated with the stimulated IFN-γ in BPF-treated NCM460 cells. Pyrogallol, pyridoxine, and N-acetylputrescine were positively associated with IL-17A levels. Collectively, the integrative analyses demonstrated an orchestrated coordination between the inflammatory response, transcriptomic, and metabolomics changes. Data presented herein provide evidence for the possible roles of BPF in the pathogenesis of intestinal inflammation. These results illustrate the advantages of using integrative analyses of high throughput datasets for characterizing the effects and mechanisms of toxicants.
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Affiliation(s)
- Yongjie Liu
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Weifeng Tang
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Junjie Ao
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Zhang
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Liping Feng
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, USA.
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Mbonye U, Leskov K, Shukla M, Valadkhan S, Karn J. Biogenesis of P-TEFb in CD4+ T cells to reverse HIV latency is mediated by protein kinase C (PKC)-independent signaling pathways. PLoS Pathog 2021; 17:e1009581. [PMID: 34529720 PMCID: PMC8478230 DOI: 10.1371/journal.ppat.1009581] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/28/2021] [Accepted: 09/04/2021] [Indexed: 01/09/2023] Open
Abstract
The switch between HIV latency and productive transcription is regulated by an auto-feedback mechanism initiated by the viral trans-activator Tat, which functions to recruit the host transcription elongation factor P-TEFb to proviral HIV. A heterodimeric complex of CDK9 and one of three cyclin T subunits, P-TEFb is expressed at vanishingly low levels in resting memory CD4+ T cells and cellular mechanisms controlling its availability are central to regulation of the emergence of HIV from latency. Using a well-characterized primary T-cell model of HIV latency alongside healthy donor memory CD4+ T cells, we characterized specific T-cell receptor (TCR) signaling pathways that regulate the generation of transcriptionally active P-TEFb, defined as the coordinate expression of cyclin T1 and phospho-Ser175 CDK9. Protein kinase C (PKC) agonists, such as ingenol and prostratin, stimulated active P-TEFb expression and reactivated latent HIV with minimal cytotoxicity, even in the absence of intracellular calcium mobilization with an ionophore. Unexpectedly, inhibition-based experiments demonstrated that PKC agonists and TCR-mobilized diacylglycerol signal through MAP kinases ERK1/2 rather than through PKC to effect the reactivation of both P-TEFb and latent HIV. Single-cell and bulk RNA-seq analyses revealed that of the four known isoforms of the Ras guanine nucleotide exchange factor RasGRP, RasGRP1 is by far the predominantly expressed diacylglycerol-dependent isoform in CD4+ T cells. RasGRP1 should therefore mediate the activation of ERK1/2 via Ras-Raf signaling upon TCR co-stimulation or PKC agonist challenge. Combined inhibition of the PI3K-mTORC2-AKT-mTORC1 pathway and the ERK1/2 activator MEK prior to TCR co-stimulation abrogated active P-TEFb expression and substantially suppressed latent HIV reactivation. Therefore, contrary to prevailing models, the coordinate reactivation of P-TEFb and latent HIV in primary T cells following either TCR co-stimulation or PKC agonist challenge is independent of PKC but rather involves two complementary signaling arms of the TCR cascade, namely, RasGRP1-Ras-Raf-MEK-ERK1/2 and PI3K-mTORC2-AKT-mTORC1.
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Affiliation(s)
- Uri Mbonye
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- * E-mail: (UM); (JK)
| | - Konstantin Leskov
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Meenakshi Shukla
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Saba Valadkhan
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- * E-mail: (UM); (JK)
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6
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Sarker M, Goliaei A, Golesi F, Poggi M, Cook A, Khan MAI, Temple BR, Stefanini L, Canault M, Bergmeier W, Campbell SL. Subcellular localization of Rap1 GTPase activator CalDAG-GEFI is orchestrated by interaction of its atypical C1 domain with membrane phosphoinositides. J Thromb Haemost 2020; 18:693-705. [PMID: 31758832 PMCID: PMC7050387 DOI: 10.1111/jth.14687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/17/2019] [Accepted: 11/14/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND The small GTPase Rap1 and its guanine nucleotide exchange factor, CalDAG-GEFI (CDGI), are critical for platelet function and hemostatic plug formation. CDGI function is regulated by a calcium binding EF hand regulatory domain and an atypical C1 domain with unknown function. OBJECTIVE Here, we investigated whether the C1 domain controls CDGI subcellular localization, both in vitro and in vivo. METHODS CDGI interaction with phosphoinositides was studied by lipid co-sedimentation assays and molecular dynamics simulations. Cellular localization of CDGI was studied in heterologous cells by immunofluorescence and subcellular fractionation assays. RESULTS Lipid co-sedimentation studies demonstrated that the CDGI C1 domain associates with membranes through exclusive recognition of phosphoinositides, phosphatidylinositol (4,5)-biphosphate (PIP2) and phosphatidylinositol (3,4,5)-triphosphate (PIP3). Molecular dynamics simulations identified a phospholipid recognition motif consisting of residues exclusive to the CDGI C1 domain. Mutation of those residues abolished co-sedimentation of the C1 domain with lipid vesicles and impaired membrane localization of CDGI in heterologous cells. CONCLUSION Our studies identify a novel interaction between an atypical C1 domain and phosphatidylinositol (4,5)-biphosphate and phosphatidylinositol (3,4,5)-triphosphate in cellular membranes, which is critical for Rap1 signaling in health and disease.
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Affiliation(s)
- Muzaddid Sarker
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ardeshir Goliaei
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - Marjorie Poggi
- Aix Marseille University, INSERM, INRA, Marseille, France
| | - Aaron Cook
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mohammad A. I. Khan
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Brenda R. Temple
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- RL Juliano Structural Bioinformatics Core, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Lucia Stefanini
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | | | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sharon L. Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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7
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Ann J, Czikora A, Saini AS, Zhou X, Mitchell GA, Lewin NE, Peach ML, Blumberg PM, Lee J. α-Arylidene Diacylglycerol-Lactones (DAG-Lactones) as Selective Ras Guanine-Releasing Protein 3 (RasGRP3) Ligands. J Med Chem 2018; 61:6261-6276. [PMID: 29860841 DOI: 10.1021/acs.jmedchem.8b00661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Diacylglycerol-lactones have proven to be a powerful template for the design of potent ligands targeting C1 domains, the recognition motif for the cellular second messenger diacylglycerol. A major objective has been to better understand the structure activity relations distinguishing the seven families of signaling proteins that contain such domains, of which the protein kinase C (PKC) and RasGRP families are of particular interest. Here, we synthesize a series of aryl- and alkyl-substituted diacylglycerol-lactones and probe their relative selectivities for RasGRP3 versus PKC. Compound 96 showed 73-fold selectivity relative to PKCα and 45-fold selectivity relative to PKCε for in vitro binding activity. Likewise, in intact cells, compound 96 induced Ras activation, a downstream response to RasGRP stimulation, with 8-29 fold selectivity relative to PKCδ S299 phosphorylation, a measure of PKCδ stimulation.
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Affiliation(s)
- Jihyae Ann
- Laboratory of Medicinal Chemistry, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
| | - Agnes Czikora
- Laboratory of Cancer Biology and Genetics , Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Amandeep S Saini
- Laboratory of Cancer Biology and Genetics , Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Xiaoling Zhou
- Laboratory of Cancer Biology and Genetics , Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Gary A Mitchell
- Laboratory of Cancer Biology and Genetics , Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Nancy E Lewin
- Laboratory of Cancer Biology and Genetics , Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Megan L Peach
- Basic Science Program, Leidos Biomedical Research Inc., Chemical Biology Laboratory , Frederick National Laboratory for Cancer Research, National Institutes of Health , Frederick , Maryland 21702 , United States
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics , Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Jeewoo Lee
- Laboratory of Medicinal Chemistry, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
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Stefanini L, Bergmeier W. RAP GTPases and platelet integrin signaling. Platelets 2018; 30:41-47. [PMID: 29863951 PMCID: PMC6312509 DOI: 10.1080/09537104.2018.1476681] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/26/2018] [Accepted: 04/27/2018] [Indexed: 12/31/2022]
Abstract
Platelets are highly specialized cells that continuously patrol the vasculature to ensure its integrity (hemostasis). At sites of vascular injury, they are able to respond to trace amounts of agonists and to rapidly transition from an anti-adhesive/patrolling to an adhesive state (integrin inside-out activation) required for hemostatic plug formation. Pathological conditions that disturb the balance in the underlying signaling processes can lead to unwanted platelet activation (thrombosis) or to an increased bleeding risk. The small GTPases of the RAP subfamily, highly expressed in platelets, are critical regulators of cell adhesion, cytoskeleton remodeling, and MAP kinase signaling. Studies by our group and others demonstrate that RAP GTPases, in particular RAP1A and RAP1B, are the key molecular switches that turn on platelet activation/adhesiveness at sites of injury. In this review, we will summarize major findings on the role of RAP GTPases in platelet biology with a focus on the signaling pathways leading to the conversion of integrins to a high-affinity state.
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Affiliation(s)
- Lucia Stefanini
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill (NC), USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill (NC), USA
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9
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Cook AA, Deng W, Ren J, Li R, Sondek J, Bergmeier W. Calcium-induced structural rearrangements release autoinhibition in the Rap-GEF CalDAG-GEFI. J Biol Chem 2018; 293:8521-8529. [PMID: 29622678 DOI: 10.1074/jbc.ra118.002712] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 03/22/2018] [Indexed: 11/06/2022] Open
Abstract
Platelets are recruited to sites of vascular injury, where they are activated and aggregate to form a hemostatic plug. This process requires the activation of the small GTPase Rap1B by its cognate guanine nucleotide exchange factor CalDAG-GEFI. Studies on platelet function suggest that CalDAG-GEFI activity is regulated by changes in cytosolic calcium, but the exact molecular mechanism is poorly understood. Here we show that purified CalDAG-GEFI is autoinhibited and directly regulated by calcium. Substitutions of putative calcium-binding residues within the canonical EF hands of CalDAG-GEFI diminish its capacity to activate Rap1B. Structural differences between active (WT) and inactive (EF hand variant) CalDAG-GEFI protein were determined by hydrogen-deuterium exchange MS. The highest differential rates of deuterium uptake in WT over EF hand variant CalDAG-GEFI were observed in regions within the catalytic Cdc25 domain and a putative autoinhibitory linker connecting the Cdc25 and EF hand domains. Exchange activity in the EF hand variant was fully restored by an additional substitution, valine 406 to glutamate, which is thought to disrupt the interface between the autoinhibitory linker and the Cdc25 domain. Overall, our results suggest a model for how CalDAG-GEFI remains in an autoinhibited state when levels of cytosolic calcium in resting platelets are low. In response to cellular stimulation, calcium mobilization and binding to the EF hands causes conformational rearrangements within CalDAG-GEFI, including the autoinhibitory linker that frees the catalytic surface of CalDAG-GEFI to engage and activate Rap1B. The data from this study are the first evidence linking CalDAG-GEFI activity directly to calcium.
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Affiliation(s)
- Aaron A Cook
- From the Departments of Biochemistry and Biophysics and
| | - Wei Deng
- the Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | | | - Renhao Li
- the Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - John Sondek
- From the Departments of Biochemistry and Biophysics and.,Pharmacology and.,the Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
| | - Wolfgang Bergmeier
- From the Departments of Biochemistry and Biophysics and .,the McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina 27516
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Vanshylla K, Bartsch C, Hitzing C, Krümpelmann L, Wienands J, Engels N. Grb2 and GRAP connect the B cell antigen receptor to Erk MAP kinase activation in human B cells. Sci Rep 2018; 8:4244. [PMID: 29523808 PMCID: PMC5844867 DOI: 10.1038/s41598-018-22544-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/19/2018] [Indexed: 11/09/2022] Open
Abstract
The B cell antigen receptor (BCR) employs enzymatically inactive adaptor proteins to facilitate activation of intracellular signaling pathways. In animal model systems, adaptor proteins of the growth factor receptor-bound 2 (Grb2) family have been shown to serve critical functions in lymphocytes. However, the roles of Grb2 and the Grb2-related adaptor protein (GRAP) in human B lymphocytes remain unclear. Using TALEN-mediated gene targeting, we show that in human B cells Grb2 and GRAP amplify signaling by the immunoglobulin tail tyrosine (ITT) motif of mIgE-containing BCRs and furthermore connect immunoreceptor tyrosine-based activation motif (ITAM) signaling to activation of the Ras-controlled Erk MAP kinase pathway. In contrast to mouse B cells, BCR-induced activation of Erk in human B cells is largely independent of phospholipase C-ɣ activity and diacylglycerol-responsive members of Ras guanine nucleotide releasing proteins. Together, our results demonstrate that Grb2 family adaptors are critical regulators of ITAM and ITT signaling in naïve and IgE-switched human B cells.
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Affiliation(s)
- Kanika Vanshylla
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Caren Bartsch
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Christoffer Hitzing
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Laura Krümpelmann
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Jürgen Wienands
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Niklas Engels
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany.
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11
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Czikora A, Pany S, You Y, Saini AS, Lewin NE, Mitchell GA, Abramovitz A, Kedei N, Blumberg PM, Das J. Structural determinants of phorbol ester binding activity of the C1a and C1b domains of protein kinase C theta. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1046-1056. [PMID: 29317197 DOI: 10.1016/j.bbamem.2018.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 12/06/2017] [Accepted: 01/04/2018] [Indexed: 12/31/2022]
Abstract
The PKC isozymes represent the most prominent family of signaling proteins mediating response to the ubiquitous second messenger diacylglycerol. Among them, PKCθ is critically involved in T-cell activation. Whereas all the other conventional and novel PKC isoforms have twin C1 domains with potent binding activity for phorbol esters, in PKCθ only the C1b domain possesses potent binding activity, with little or no activity reported for the C1a domain. In order to better understand the structural basis accounting for the very weak ligand binding of the PKCθ C1a domain, we assessed the effect on ligand binding of twelve amino acid residues which differed between the C1a and C1b domains of PKCθ. Mutation of Pro9 of the C1a domain of PKCθ to the corresponding Lys9 found in C1b restored in vitro binding activity for [3H]phorbol 12,13-dibutyrate to 3.6 nM, whereas none of the other residues had substantial effect. Interestingly, the converse mutation in the C1b domain of Lys9 to Pro9 only diminished binding affinity to 11.7 nM, compared to 254 nM in the unmutated C1a. In confocal experiments, deletion of the C1b domain from full length PKCθ diminished, whereas deletion of the C1a domain enhanced 5-fold (at 100 nM PMA) the translocation to the plasma membrane. We conclude that the Pro168 residue in the C1a domain of full length PKCθ plays a critical role in the ligand and membrane binding, while exchanging the residue (Lys240) at the same position in C1b domain of full length PKCθ only modestly reduced the membrane interaction.
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Affiliation(s)
- Agnes Czikora
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States
| | - Satyabrata Pany
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204, United States
| | - Youngki You
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204, United States
| | - Amandeep S Saini
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States
| | - Nancy E Lewin
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States
| | - Gary A Mitchell
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States
| | - Adelle Abramovitz
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States
| | - Noemi Kedei
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States.
| | - Joydip Das
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204, United States.
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Das J, Kedei N, Kelsey JS, You Y, Pany S, Mitchell GA, Lewin NE, Blumberg PM. Critical Role of Trp-588 of Presynaptic Munc13-1 for Ligand Binding and Membrane Translocation. Biochemistry 2018; 57:732-741. [PMID: 29244485 DOI: 10.1021/acs.biochem.7b00764] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Munc13-1 is a presynaptic active-zone protein essential for neurotransmitter release and presynaptic plasticity in the brain. This multidomain scaffold protein contains a C1 domain that binds to the activator diacylglycerol/phorbol ester. Although the C1 domain bears close structural homology with the C1 domains of protein kinase C (PKC), the tryptophan residue at position 22 (588 in the full-length Munc13-1) occludes the activator binding pocket, which is not the case for PKC. To elucidate the role of this tryptophan, we generated W22A, W22K, W22D, W22Y, and W22F substitutions in the full-length Munc13-1, expressed the GFP-tagged constructs in Neuro-2a cells, and measured their membrane translocation in response to phorbol ester treatment by imaging of the live cells using confocal microscopy. The extent of membrane translocation followed the order, wild-type > W22K > W22F > W22Y > W22A > W22D. The phorbol ester binding affinity of the wild-type Munc13-1C1 domain and its mutants was phosphatidylserine (PS)-dependent following the order, wild-type > W22K > W22A ≫ W22D in both 20% and 100% PS. Phorbol ester affinity was higher for Munc13-1 than the C1 domain. While Munc13-1 translocated to the plasma membrane, the C1 domain translocated to internal membranes in response to phorbol ester. Molecular dynamics (80 ns) studies reveal that Trp-22 is relatively less flexible than the homologous Trp-22 of PKCδ and PKCθ. Results are discussed in terms of the overall negative charge state of the Munc13-1C1 domain and its possible interaction with the PS-rich plasma membrane. This study shows that Trp-588 is an important structural element for ligand binding and membrane translocation in Munc13-1.
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Affiliation(s)
- Joydip Das
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston , Houston, Texas 77204, United States
| | - Noemi Kedei
- Center for Cancer Research, National Cancer Institute , Bethesda, Maryland 20892, United States
| | - Jessica S Kelsey
- Center for Cancer Research, National Cancer Institute , Bethesda, Maryland 20892, United States
| | - Youngki You
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston , Houston, Texas 77204, United States
| | - Satyabrata Pany
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston , Houston, Texas 77204, United States
| | - Gary A Mitchell
- Center for Cancer Research, National Cancer Institute , Bethesda, Maryland 20892, United States
| | - Nancy E Lewin
- Center for Cancer Research, National Cancer Institute , Bethesda, Maryland 20892, United States
| | - Peter M Blumberg
- Center for Cancer Research, National Cancer Institute , Bethesda, Maryland 20892, United States
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13
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Kelsey JS, Géczy T, Kaler CJ, Blumberg PM. The C1 domain of Vav3, a novel potential therapeutic target. Cell Signal 2017; 40:133-142. [PMID: 28927664 PMCID: PMC5651187 DOI: 10.1016/j.cellsig.2017.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 08/22/2017] [Accepted: 09/14/2017] [Indexed: 12/12/2022]
Abstract
Vav1/2/3 comprise a protein family with guanyl nucleotide exchange activity for Rho and Rac as well as with motifs conferring adapter activity. Biologically, Vav1 plays a critical role in hematologic cell signaling, whereas Vav2/3 have a wider tissue distribution, but all 3 Vav proteins are implicated in cancer development. A structural feature of Vav1/2/3 is the presence of an atypical C1 domain, which possesses close structural homology to the typical C1 domains of protein kinase C but which fails to bind the second messenger diacylglycerol or the potent analogs, the phorbol esters. Previously, we have shown that five residues in the Vav1 C1 domain are responsible for its lack of phorbol ester binding. Here, we show that the lack of phorbol ester binding of Vav3 has a similar basis. We then explore the consequences of phorbol ester binding to a modified Vav3 in which the C1 domain has been altered to allow phorbol ester binding. We find both disruption of the guanyl nucleotide exchange activity of the modified Vav 3 as well as a shift in localization to the membrane upon phorbol ester treatment. This change in localization is associated with altered interactions with other signaling proteins. The studies provide a first step in assessing the potential for the design of custom C1 domain targeted molecules selective for the atypical C1 domains of Vav family proteins.
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Affiliation(s)
- Jessica S Kelsey
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Tamás Géczy
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Christopher J Kaler
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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14
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Estevez B, Du X. New Concepts and Mechanisms of Platelet Activation Signaling. Physiology (Bethesda) 2017; 32:162-177. [PMID: 28228483 DOI: 10.1152/physiol.00020.2016] [Citation(s) in RCA: 190] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Upon blood vessel injury, platelets are exposed to adhesive proteins in the vascular wall and soluble agonists, which initiate platelet activation, leading to formation of hemostatic thrombi. Pathological activation of platelets can induce occlusive thrombosis, resulting in ischemic events such as heart attack and stroke, which are leading causes of death globally. Platelet activation requires intracellular signal transduction initiated by platelet receptors for adhesion proteins and soluble agonists. Whereas many platelet activation signaling pathways have been established for many years, significant recent progress reveals much more complex and sophisticated signaling and amplification networks. With the discovery of new receptor signaling pathways and regulatory networks, some of the long-standing concepts of platelet signaling have been challenged. This review provides an overview of the new developments and concepts in platelet activation signaling.
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Affiliation(s)
- Brian Estevez
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Xiaoping Du
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
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15
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Niemz J, Kliche S, Pils MC, Morrison E, Manns A, Freund C, Crittenden JR, Graybiel AM, Galla M, Jänsch L, Huehn J. The Guanine-Nucleotide Exchange Factor Caldag Gefi Fine-Tunes Functional Properties of Regulatory T Cells. Eur J Microbiol Immunol (Bp) 2017; 7:112-126. [PMID: 28690878 PMCID: PMC5495083 DOI: 10.1556/1886.2017.00007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 04/27/2017] [Indexed: 12/12/2022] Open
Abstract
Using quantitative phosphopeptide sequencing of unstimulated versus stimulated primary murine Foxp3+ regulatory and Foxp3– conventional T cells (Tregs and Tconv, respectively), we detected a novel and differentially regulated tyrosine phosphorylation site within the C1 domain of the guanine-nucleotide exchange factor CalDAG GEFI. We hypothesized that the Treg-specific and activation-dependent reduced phosphorylation at Y523 allows binding of CalDAG GEFI to diacylglycerol, thereby impacting the formation of a Treg-specific immunological synapse. However, diacylglycerol binding assays of phosphomutant C1 domains of CalDAG GEFI could not confirm this hypothesis. Moreover, CalDAG GEFI–/– mice displayed normal Treg numbers in thymus and secondary lymphoid organs, and CalDAG GEFI–/– Tregs showed unaltered in vitro suppressive capacity when compared to CalDAG GEFI+/+ Tregs. Interestingly, when tested in vivo, CalDAG GEFI–/– Tregs displayed a slightly reduced suppressive ability in the transfer colitis model when compared to CalDAG GEFI+/+ Tregs. Additionally, CRISPR-Cas9-generated CalDAG GEFI–/– Jurkat T cell clones showed reduced adhesion to ICAM-1 and fibronectin when compared to CalDAG GEFI-competent Jurkat T cells. Therefore, we speculate that deficiency in CalDAG GEFI impairs adherence of Tregs to antigen-presenting cells, thereby impeding formation of a fully functional immunological synapse, which finally results in a reduced suppressive potential.
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Affiliation(s)
- Jana Niemz
- Experimental Immunology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Stefanie Kliche
- Institute of Molecular and Clinical Immunology, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Marina C Pils
- Mousepathology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Eliot Morrison
- Institute for Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany
| | - Annika Manns
- Institute for Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany
| | - Christian Freund
- Institute for Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany
| | - Jill R Crittenden
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Ann M Graybiel
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Melanie Galla
- Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany
| | - Lothar Jänsch
- Cellular Proteomics, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Jochen Huehn
- Experimental Immunology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
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16
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Cooke M, Magimaidas A, Casado-Medrano V, Kazanietz MG. Protein kinase C in cancer: The top five unanswered questions. Mol Carcinog 2017; 56:1531-1542. [PMID: 28112438 DOI: 10.1002/mc.22617] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/04/2017] [Accepted: 01/20/2017] [Indexed: 12/29/2022]
Abstract
Few kinases have been studied as extensively as protein kinase C (PKC), particularly in the context of cancer. As major cellular targets for the phorbol ester tumor promoters and diacylglycerol (DAG), a second messenger generated by stimulation of membrane receptors, PKC isozymes play major roles in the control of signaling pathways associated with proliferation, migration, invasion, tumorigenesis, and metastasis. However, despite decades of research, fundamental questions remain to be answered or are the subject of intense controversy. Primary among these unresolved issues are the role of PKC isozymes as either tumor promoter or tumor suppressor kinases and the incomplete understanding on isozyme-specific substrates and effectors. The involvement of PKC isozymes in cancer progression needs to be reassessed in the context of specific oncogenic and tumor suppressing alterations. In addition, there are still major hurdles in addressing isozyme-specific function due to the limited specificity of most pharmacological PKC modulators and the lack of validated predictive biomarkers for response, which impacts the translation of these agents to the clinic. In this review we focus on key controversial issues and upcoming challenges, with the expectation that understanding the intricacies of PKC function will help fulfill the yet unsuccessful promise of targeting PKCs for cancer therapeutics.
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Affiliation(s)
- Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Andrew Magimaidas
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Victoria Casado-Medrano
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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