1
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Chmiest D, Podavini S, Ioannidou K, Vallois D, Décaillet C, Gonzalez M, Quadroni M, Blackney K, Schairer R, de Leval L, Thome M. PD1 inhibits PKCθ-dependent phosphorylation of cytoskeleton-related proteins and immune synapse formation. Blood Adv 2024; 8:2908-2923. [PMID: 38513140 DOI: 10.1182/bloodadvances.2023011901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 02/02/2024] [Accepted: 02/20/2024] [Indexed: 03/23/2024] Open
Abstract
ABSTRACT The inhibitory surface receptor programmed cell death protein 1 (PD1) is a major target for antibody-based cancer immunotherapies. Nevertheless, a substantial number of patients fail to respond to the treatment or experience adverse effects. An improved understanding of intracellular pathways targeted by PD1 is thus needed to develop better predictive and prognostic biomarkers. Here, via unbiased phosphoproteome analysis of primary human T cells, we demonstrate that PD1 triggering inhibited the phosphorylation and physical association with protein kinase Cθ (PKCθ) of a variety of cytoskeleton-related proteins. PD1 blocked activation and recruitment of PKCθ to the forming immune synapse (IS) in a Src homology-2 domain-containing phosphatase-1/2 (SHP1/SHP2)-dependent manner. Consequently, PD1 engagement led to impaired synaptic phosphorylation of cytoskeleton-related proteins and formation of smaller IS. T-cell receptor induced phosphorylation of the PKCθ substrate and binding partner vimentin was long-lasting and it could be durably inhibited by PD1 triggering. Vimentin phosphorylation in intratumoral T cells also inversely correlated with the levels of the PD1 ligand, PDL1, in human lung carcinoma. Thus, PKCθ and its substrate vimentin represent important targets of PD1-mediated T-cell inhibition, and low levels of vimentin phosphorylation may serve as a biomarker for the activation of the PD1 pathway.
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Affiliation(s)
- Daniela Chmiest
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | - Silvia Podavini
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | - Kalliopi Ioannidou
- Department of Laboratory Medicine and Pathology, Institute of Pathology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - David Vallois
- Department of Laboratory Medicine and Pathology, Institute of Pathology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Chantal Décaillet
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | | | - Manfredo Quadroni
- Protein Analysis Facility, University of Lausanne, Lausanne, Switzerland
| | - Kevin Blackney
- Flow Cytometry Facility, Department of Formation and Research, University of Lausanne, Epalinges, Switzerland
| | - Rebekka Schairer
- Department of Internal Medicine II, Hematology, Oncology, Clinical Immunology, and Rheumatology, University Hospital Tübingen, Tübingen, Germany
| | - Laurence de Leval
- Department of Laboratory Medicine and Pathology, Institute of Pathology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Margot Thome
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
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2
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Saiz-Baggetto S, Dolz-Edo L, Méndez E, García-Bolufer P, Marí M, Bañó MC, Fariñas I, Morante-Redolat JM, Igual JC, Quilis I. A Multimodel Study of the Role of Novel PKC Isoforms in the DNA Integrity Checkpoint. Int J Mol Sci 2023; 24:15796. [PMID: 37958781 PMCID: PMC10650207 DOI: 10.3390/ijms242115796] [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] [Received: 09/28/2023] [Revised: 10/22/2023] [Accepted: 10/29/2023] [Indexed: 11/15/2023] Open
Abstract
The protein kinase C (PKC) family plays important regulatory roles in numerous cellular processes. Saccharomyces cerevisiae contains a single PKC, Pkc1, whereas in mammals, the PKC family comprises nine isoforms. Both Pkc1 and the novel isoform PKCδ are involved in the control of DNA integrity checkpoint activation, demonstrating that this mechanism is conserved from yeast to mammals. To explore the function of PKCδ in a non-tumor cell line, we employed CRISPR-Cas9 technology to obtain PKCδ knocked-out mouse embryonic stem cells (mESCs). This model demonstrated that the absence of PKCδ reduced the activation of the effector kinase CHK1, although it suggested that other isoform(s) might contribute to this function. Therefore, we used yeast to study the ability of each single PKC isoform to activate the DNA integrity checkpoint. Our analysis identified that PKCθ, the closest isoform to PKCδ, was also able to perform this function, although with less efficiency. Then, by generating truncated and mutant versions in key residues, we uncovered differences between the activation mechanisms of PKCδ and PKCθ and identified their essential domains. Our work strongly supports the role of PKC as a key player in the DNA integrity checkpoint pathway and highlights the advantages of combining distinct research models.
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Affiliation(s)
- Sara Saiz-Baggetto
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
| | - Laura Dolz-Edo
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - Ester Méndez
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
| | - Pau García-Bolufer
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - Miquel Marí
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - M. Carmen Bañó
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
| | - Isabel Fariñas
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - José Manuel Morante-Redolat
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - J. Carlos Igual
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
| | - Inma Quilis
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
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3
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zur Nedden S, Safari MS, Fresser F, Faserl K, Lindner H, Sarg B, Baier G, Baier-Bitterlich G. PKN1 Exerts Neurodegenerative Effects in an In Vitro Model of Cerebellar Hypoxic-Ischemic Encephalopathy via Inhibition of AKT/GSK3β Signaling. Biomolecules 2023; 13:1599. [PMID: 38002281 PMCID: PMC10669522 DOI: 10.3390/biom13111599] [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] [Received: 09/29/2023] [Revised: 10/18/2023] [Accepted: 10/20/2023] [Indexed: 11/26/2023] Open
Abstract
We recently identified protein kinase N1 (PKN1) as a negative gatekeeper of neuronal AKT protein kinase activity during postnatal cerebellar development. The developing cerebellum is specifically vulnerable to hypoxia-ischemia (HI), as it occurs during hypoxic-ischemic encephalopathy, a condition typically caused by oxygen deprivation during or shortly after birth. In that context, activation of the AKT cell survival pathway has emerged as a promising new target for neuroprotective interventions. Here, we investigated the role of PKN1 in an in vitro model of HI, using postnatal cerebellar granule cells (Cgc) derived from Pkn1 wildtype and Pkn1-/- mice. Pkn1-/- Cgc showed significantly higher AKT phosphorylation, resulting in reduced caspase-3 activation and improved survival after HI. Pkn1-/- Cgc also showed enhanced axonal outgrowth on growth-inhibitory glial scar substrates, further pointing towards a protective phenotype of Pkn1 knockout after HI. The specific PKN1 phosphorylation site S374 was functionally relevant for the enhanced axonal outgrowth and AKT interaction. Additionally, PKN1pS374 shows a steep decrease during cerebellar development. In summary, we demonstrate the pathological relevance of the PKN1-AKT interaction in an in vitro HI model and establish the relevant PKN1 phosphorylation sites, contributing important information towards the development of specific PKN1 inhibitors.
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Affiliation(s)
- Stephanie zur Nedden
- Institute of Neurobiochemistry, CCB-Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Motahareh Solina Safari
- Institute of Neurobiochemistry, CCB-Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Friedrich Fresser
- Institute for Cell Genetics, Medical University of Innsbruck, 6020 Innsbruck, Austria; (F.F.); (G.B.)
| | - Klaus Faserl
- Protein Core Facility, Institute of Medical Biochemistry, CCB-Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (K.F.); (H.L.); (B.S.)
| | - Herbert Lindner
- Protein Core Facility, Institute of Medical Biochemistry, CCB-Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (K.F.); (H.L.); (B.S.)
| | - Bettina Sarg
- Protein Core Facility, Institute of Medical Biochemistry, CCB-Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (K.F.); (H.L.); (B.S.)
| | - Gottfried Baier
- Institute for Cell Genetics, Medical University of Innsbruck, 6020 Innsbruck, Austria; (F.F.); (G.B.)
| | - Gabriele Baier-Bitterlich
- Institute of Neurobiochemistry, CCB-Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
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4
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Koch KC, Tew GN. Functional antibody delivery: Advances in cellular manipulation. Adv Drug Deliv Rev 2023; 192:114586. [PMID: 36280179 DOI: 10.1016/j.addr.2022.114586] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/10/2022] [Accepted: 10/18/2022] [Indexed: 02/03/2023]
Abstract
The current therapeutic antibody market in the U.S. consists of 100 antibody-based products and their market value is expected to explode beyond $300 billion by 2025. These therapies are presently limited to extracellular targets due to the innate inability of antibodies to transverse membranes. To expand the number of accessible therapeutic targets, intracellular antibody delivery is necessary. Many delivery vehicles for antibodies have been used with some promising results, such as nanoparticles and cell penetrating polymers. Despite the success of these delivery platforms using model antibody cargo, there is a surprisingly small number of studies that focus on functional antibody delivery into the cytosol that also measures a cellular response. Antibodies can be designed for essentially unlimited targets, including proteins and DNA, that will ultimately control cell function once delivered inside cells. Advancement in cellular manipulation depends on the application of intracellularly delivering functional antibodies to achieve a desired result. This review focuses on the emerging field of functional antibody delivery which enables various cellular responses and cell manipulation.
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Affiliation(s)
- Kayla C Koch
- Department of Polymer Science & Engineering, University of Massachusetts, Amherst, MA 01003, United States
| | - Gregory N Tew
- Department of Polymer Science & Engineering, University of Massachusetts, Amherst, MA 01003, United States; Molecular & Cellular Biology Program, University of Massachusetts, Amherst, MA 01003, United States; Department of Veterinary & Animal Sciences, University of Massachusetts, Amherst, MA 01003, United States.
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5
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Chen X, Song X, Li J, Zhang R, Yu C, Zhou Z, Liu J, Liao S, Klionsky DJ, Kroemer G, Liu J, Tang D, Kang R. Identification of HPCAL1 as a specific autophagy receptor involved in ferroptosis. Autophagy 2023; 19:54-74. [PMID: 35403545 PMCID: PMC9809962 DOI: 10.1080/15548627.2022.2059170] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Selective macroautophagy/autophagy maintains cellular homeostasis through the lysosomal degradation of specific cellular proteins or organelles. The pro-survival effect of selective autophagy has been well-characterized, but the mechanism by which it drives cell death is still poorly understood. Here, we use a quantitative proteomic approach to identify HPCAL1 (hippocalcin like 1) as a novel autophagy receptor for the selective degradation of CDH2 (cadherin 2) during ferroptosis. HPCAL1-dependent CDH2 depletion increases susceptibility to ferroptotic death by reducing membrane tension and favoring lipid peroxidation. Site-directed mutagenesis aided by bioinformatic analyses revealed that the autophagic degradation of CDH2 requires PRKCQ (protein kinase C theta)-mediated HPCAL1 phosphorylation on Thr149, as well as a non-classical LC3-interacting region motif located between amino acids 46-51. An unbiased drug screening campaign involving 4208 small molecule compounds led to the identification of a ferroptosis inhibitor that suppressed HPCAL1 expression. The genetic or pharmacological inhibition of HPCAL1 prevented ferroptosis-induced tumor suppression and pancreatitis in suitable mouse models. These findings provide a framework for understanding how selective autophagy promotes ferroptotic cell death.Abbreviations: ANXA7: annexin A7; ARNTL: aryl hydrocarbon receptor nuclear translocator like; CCK8: cell counting kit-8; CDH2: cadherin 2; CETSAs: cellular thermal shift assays; CPT2: carnitine palmitoyltransferase 2; DAMP, danger/damage-associated molecular pattern; DPPH: 2,2-diphenyl-1-picrylhydrazyl; DFO: deferoxamine; EBNA1BP2: EBNA1 binding protein 2; EIF4G1: eukaryotic translation initiation factor 4 gamma 1; FBL: fibrillarin; FKBP1A: FKBP prolyl isomerase 1A; FTH1: ferritin heavy chain 1; GPX4: glutathione peroxidase 4; GSDMs: gasdermins; HBSS: Hanks' buffered salt solution; HMGB1: high mobility group box 1; HNRNPUL1: heterogeneous nuclear ribonucleoprotein U like 1; HPCAL1: hippocalcin like 1; H1-3/HIST1H1D: H1.3 linker histone, cluster member; IKE: imidazole ketone erastin; KD: knockdown; LDH: lactate dehydrogenase; LIR: LC3-interacting region; MAGOH: mago homolog, exon junction complex subunit; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; MDA: malondialdehyde; MLKL: mixed lineage kinase domain like pseudokinase; MPO: myeloperoxidase; MTOR: mechanistic target of rapamycin kinase; OE: overexpressing; OSTM1: osteoclastogenesis associated transmembrane protein 1; PRKC/PKC: protein kinase C; PRKAR1A: protein kinase cAMP-dependent type I regulatory subunit alpha; PRDX3: peroxiredoxin 3; PTGS2: prostaglandin-endoperoxide synthase 2; ROS: reactive oxygen species; SLC7A11: solute carrier family 7 member 11; SLC40A1: solute carrier family 40 member 1; SPTAN1: spectrin alpha, non-erythrocytic 1; STS: staurosporine; UBE2M: ubiquitin conjugating enzyme E2 M; ZYX: zyxin.
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Affiliation(s)
- Xin Chen
- DAMP Lab, The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China,Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, Guangdong, China,Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA,CONTACT Xin Chen DAMP Lab, The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Xinxin Song
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jingbo Li
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ruoxi Zhang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Chunhua Yu
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Zhuan Zhou
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jiao Liu
- DAMP Lab, The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Siyan Liao
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Daniel J. Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, INSERM U1138, Institut Universitaire de France, Paris, France,Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France,Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Jinbao Liu
- DAMP Lab, The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China,Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, Guangdong, China,Jinbao Liu Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China
| | - Daolin Tang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA,Daolin Tang Department of Surgery, UT Southwestern Medical Center, Dallas, USA
| | - Rui Kang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA,Rui Kang Department of Surgery, UT Southwestern Medical Center, Dallas, USA
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6
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Migliavacca J, Züllig B, Capdeville C, Grotzer MA, Baumgartner M. Cooperation of Striatin 3 and MAP4K4 promotes growth and tissue invasion. Commun Biol 2022; 5:795. [PMID: 35941177 PMCID: PMC9360036 DOI: 10.1038/s42003-022-03708-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/12/2022] [Indexed: 11/09/2022] Open
Abstract
MAP4K4 is associated with increased motility and reduced proliferation in tumor cells, but the regulation of this dichotomous functionality remained elusive. We find that MAP4K4 interacts with striatin 3 and 4 (STRN3/4) and that STRN3 and MAP4K4 exert opposing functions in Hippo signaling and clonal growth. However, depletion of either STRN3 or MAP4K4 in medulloblastoma cells reduces invasion, and loss of both proteins abrogates tumor cell growth in the cerebellar tissue. Mechanistically, STRN3 couples MAP4K4 to the protein phosphatase 2A, which inactivates growth repressing activities of MAP4K4. In parallel, STRN3 enables growth factor-induced PKCθ activation and direct phosphorylation of VASPS157 by MAP4K4, which both are necessary for efficient cell invasion. VASPS157 directed activity of MAP4K4 and STRN3 requires the CNH domain of MAP4K4, which mediates its interaction with striatins. Thus, STRN3 is a master regulator of MAP4K4 function, and disruption of its cooperation with MAP4K4 reactivates Hippo signaling and represses tissue invasion in medulloblastoma. Analysis of the MAP4K4-STRN3 cooperation in medulloblastoma reveals its opposing regulation of Hippo activation and tissue invasion in cancer.
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Affiliation(s)
- Jessica Migliavacca
- Pediatric Molecular Neuro-Oncology Research, Division of Oncology, Children's Research Center, University Children's Hospital Zürich, Zürich, Switzerland
| | - Buket Züllig
- Pediatric Molecular Neuro-Oncology Research, Division of Oncology, Children's Research Center, University Children's Hospital Zürich, Zürich, Switzerland
| | - Charles Capdeville
- Pediatric Molecular Neuro-Oncology Research, Division of Oncology, Children's Research Center, University Children's Hospital Zürich, Zürich, Switzerland
| | - Michael A Grotzer
- Division of Oncology, University Children's Hospital Zürich, Zürich, Switzerland
| | - Martin Baumgartner
- Pediatric Molecular Neuro-Oncology Research, Division of Oncology, Children's Research Center, University Children's Hospital Zürich, Zürich, Switzerland.
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Selective Targeting of Protein Kinase C (PKC)-θ Nuclear Translocation Reduces Mesenchymal Gene Signatures and Reinvigorates Dysfunctional CD8 + T Cells in Immunotherapy-Resistant and Metastatic Cancers. Cancers (Basel) 2022; 14:cancers14061596. [PMID: 35326747 PMCID: PMC8946217 DOI: 10.3390/cancers14061596] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 02/05/2023] Open
Abstract
Simple Summary Some important signaling proteins that control how cells grow and behave not only act in the cytoplasm but also in the nucleus, where they tether to chromatin. This is especially true for protein kinase C (PKC)-θ, which acts in the nucleus to mediate cancer hallmarks that drive metastasis and in normal T cells. However, current PKC-θ inhibitors are either non-specific or target only its cytoplasmic function. In a bid to develop a novel class of PKC-θ inhibitor that maintains cytoplasmic signaling but inhibits its nuclear function, here we present a novel PKC-θ inhibitor (nPKC-θi2) that specifically inhibits nuclear translocation of PKC-θ without interrupting normal signaling in healthy T cells. We show for the first time that nPKC-θ mediates immunotherapy resistance via its activity in circulating tumor cells and dysfunctional CD8+ T cells. Our novel inhibitor provides a means to target this process by simultaneously overcoming T-cell exhaustion and cancer stem cell burden. As part of a sequential approach with other therapies, this work paves the way for improving outcomes in cancer patients with immunotherapy-resistant relapse and metastasis. Abstract Protein kinase C (PKC)-θ is a serine/threonine kinase with both cytoplasmic and nuclear functions. Nuclear chromatin-associated PKC-θ (nPKC-θ) is increasingly recognized to be pathogenic in cancer, whereas its cytoplasmic signaling is restricted to normal T-cell function. Here we show that nPKC-θ is enriched in circulating tumor cells (CTCs) in patients with triple-negative breast cancer (TNBC) brain metastases and immunotherapy-resistant metastatic melanoma and is associated with poor survival in immunotherapy-resistant disease. To target nPKC-θ, we designed a novel PKC-θ peptide inhibitor (nPKC-θi2) that selectively inhibits nPKC-θ nuclear translocation but not PKC-θ signaling in healthy T cells. Targeting nPKC-θ reduced mesenchymal cancer stem cell signatures in immunotherapy-resistant CTCs and TNBC xenografts. PKC-θ was also enriched in the nuclei of CD8+ T cells isolated from stage IV immunotherapy-resistant metastatic cancer patients. We show for the first time that nPKC-θ complexes with ZEB1, a key repressive transcription factor in epithelial-to-mesenchymal transition (EMT), in immunotherapy-resistant dysfunctional PD1+/CD8+ T cells. nPKC-θi2 inhibited the ZEB1/PKC-θ repressive complex to induce cytokine production in CD8+ T cells isolated from patients with immunotherapy-resistant disease. These data establish for the first time that nPKC-θ mediates immunotherapy resistance via its activity in CTCs and dysfunctional CD8+ T cells. Disrupting nPKC-θ but retaining its cytoplasmic function may offer a means to target metastases in combination with chemotherapy or immunotherapy.
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8
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Prado DS, Cattley RT, Shipman CW, Happe C, Lee M, Boggess WC, MacDonald ML, Hawse WF. Synergistic and additive interactions between receptor signaling networks drive the regulatory T cell versus T helper 17 cell fate choice. J Biol Chem 2021; 297:101330. [PMID: 34688667 PMCID: PMC8645459 DOI: 10.1016/j.jbc.2021.101330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/09/2021] [Accepted: 10/11/2021] [Indexed: 12/04/2022] Open
Abstract
CD4+ T cells differentiate into subsets that promote immunity or minimize damage to the host. T helper 17 cells (Th17) are effector cells that function in inflammatory responses. T regulatory cells (Tregs) maintain tolerance and prevent autoimmunity by secreting immunosuppressive cytokines and expressing check point receptors. While the functions of Th17 and Treg cells are different, both cell fate trajectories require T cell receptor (TCR) and TGF-β receptor (TGF-βR) signals, and Th17 polarization requires an additional IL-6 receptor (IL-6R) signal. Utilizing high-resolution phosphoproteomics, we identified that both synergistic and additive interactions between TCR, TGF-βR, and IL-6R shape kinase signaling networks to differentially regulate key pathways during the early phase of Treg versus Th17 induction. Quantitative biochemical analysis revealed that CD4+ T cells integrate receptor signals via SMAD3, which is a mediator of TGF-βR signaling. Treg induction potentiates the formation of the canonical SMAD3/4 trimer to activate a negative feedback loop through kinases PKA and CSK to suppress TCR signaling, phosphatidylinositol metabolism, and mTOR signaling. IL-6R signaling activates STAT3 to bind SMAD3 and block formation of the SMAD3/4 trimer during the early phase of Th17 induction, which leads to elevated TCR and PI3K signaling. These data provide a biochemical mechanism by which CD4+ T cells integrate TCR, TGF-β, and IL-6 signals via generation of alternate SMAD3 complexes that control the development of early signaling networks to potentiate the choice of Treg versus Th17 cell fate.
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Affiliation(s)
- Douglas S Prado
- Department of Immunology and Center for Systems Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Richard T Cattley
- Department of Immunology and Center for Systems Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Corey W Shipman
- Department of Immunology and Center for Systems Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Cassandra Happe
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mijoon Lee
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - William C Boggess
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Matthew L MacDonald
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - William F Hawse
- Department of Immunology and Center for Systems Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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9
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Nicolle A, Zhang Y, Belguise K. The Emerging Function of PKCtheta in Cancer. Biomolecules 2021; 11:biom11020221. [PMID: 33562506 PMCID: PMC7915540 DOI: 10.3390/biom11020221] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/22/2021] [Accepted: 02/02/2021] [Indexed: 12/30/2022] Open
Abstract
Protein Kinase C theta (PKCθ) is a serine/threonine kinase that belongs to the novel PKC subfamily. In normal tissue, its expression is restricted to skeletal muscle cells, platelets and T lymphocytes in which PKCθ controls several essential cellular processes such as survival, proliferation and differentiation. Particularly, PKCθ has been extensively studied for its role in the immune system where its translocation to the immunological synapse plays a critical role in T cell activation. Beyond its physiological role in immune responses, increasing evidence implicates PKCθ in the pathology of various diseases, especially autoimmune disorders and cancers. In this review, we discuss the implication of PKCθ in various types of cancers and the PKCθ-mediated signaling events controlling cancer initiation and progression. In these types of cancers, the high PKCθ expression leads to aberrant cell proliferation, migration and invasion resulting in malignant phenotype. The recent development and application of PKCθ inhibitors in the context of autoimmune diseases could benefit the emergence of treatment for cancers in which PKCθ has been implicated.
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Metz R, Rust S, Duhadaway JB, Mautino MR, Munn DH, Vahanian NN, Link CJ, Prendergast GC. IDO inhibits a tryptophan sufficiency signal that stimulates mTOR: A novel IDO effector pathway targeted by D-1-methyl-tryptophan. Oncoimmunology 2021; 1:1460-1468. [PMID: 23264892 PMCID: PMC3525601 DOI: 10.4161/onci.21716] [Citation(s) in RCA: 289] [Impact Index Per Article: 96.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tryptophan catabolism by indoleamine 2,3-dioxygenase (IDO) alters inflammation and favors T-cell tolerance in cancer, but the underlying molecular mechanisms remain poorly understood. The integrated stress response kinase GCN2, a sensor of uncharged tRNA that is activated by amino acid deprivation, is recognized as an important effector of the IDO pathway. However, in a mouse model of inflammatory carcinogenesis, ablation of Gcn2 did not promote resistance against tumor development like the absence of IDO does, implying the existence of additional cancer-relevant pathways that operate downstream of IDO. Addressing this gap in knowledge, we report that the IDO-mediated catabolism of tryptophan also inhibits the immunoregulatory kinases mTOR and PKC-Θ, along with the induction of autophagy. These effects were relieved specifically by tryptophan but also by the experimental agent 1-methyl-D-tryptophan (D-1MT, also known as NLG8189), the latter of which reversed the inhibitory signals generated by IDO with higher potency. Taken together, our results implicate mTOR and PKC-Θ in IDO-mediated immunosuppressive signaling, and they provide timely insights into the unique mechanism of action of D-1MT as compared with traditional biochemical inhibitors of IDO. These findings are important translationally, because they suggest broader clinical uses for D-1MT against cancers that overexpress any tryptophan catabolic enzyme (IDO, IDO2 or TDO). Moreover, they define mTOR and PKC-Θ as candidate pharmacodynamic markers for D-1MT responses in patients recruited to ongoing phase IB/II cancer trials, addressing a current clinical need.
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11
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Ether lipid metabolism by AADACL1 regulates platelet function and thrombosis. Blood Adv 2020; 3:3818-3828. [PMID: 31770438 DOI: 10.1182/bloodadvances.2018030767] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 09/28/2019] [Indexed: 12/25/2022] Open
Abstract
We previously reported the discovery of a novel lipid deacetylase in platelets, arylacetamide deacetylase-like 1 (AADACL1/NCEH1), and that its inhibition impairs agonist-induced platelet aggregation, Rap1 GTP loading, protein kinase C (PKC) activation, and ex vivo thrombus growth. However, precise mechanisms by which AADACL1 impacts platelet signaling and function in vivo are currently unknown. Here, we demonstrate that AADACL1 regulates the accumulation of ether lipids that impact PKC signaling networks crucial for platelet activation in vitro and in vivo. Human platelets treated with the AADACL1 inhibitor JW480 or the AADACL1 substrate 1-O-hexadecyl-2-acetyl-sn-glycerol (HAG) exhibited decreased platelet aggregation, granule secretion, Ca2+ flux, and PKC phosphorylation. Decreased aggregation and secretion were rescued by exogenous adenosine 5'-diphosphate, indicating that AADACL1 likely functions to induce dense granule secretion. Experiments with P2Y12-/- and CalDAG GEFI-/- mice revealed that the P2Y12 pathway is the predominate target of HAG-mediated inhibition of platelet aggregation. HAG itself displayed weak agonist properties and likely mediates its inhibitory effects via conversion to a phosphorylated metabolite, HAGP, which directly interacted with the C1a domains of 2 distinct PKC isoforms and blocked PKC kinase activity in vitro. Finally, AADACL1 inhibition in rats reduced platelet aggregation, protected against FeCl3-induced arterial thrombosis, and delayed tail bleeding time. In summary, our data support a model whereby AADACL1 inhibition shifts the platelet ether lipidome to an inhibitory axis of HAGP accumulation that impairs PKC activation, granule secretion, and recruitment of platelets to sites of vascular damage.
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12
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Adderley JD, John von Freyend S, Jackson SA, Bird MJ, Burns AL, Anar B, Metcalf T, Semblat JP, Billker O, Wilson DW, Doerig C. Analysis of erythrocyte signalling pathways during Plasmodium falciparum infection identifies targets for host-directed antimalarial intervention. Nat Commun 2020; 11:4015. [PMID: 32782246 PMCID: PMC7419518 DOI: 10.1038/s41467-020-17829-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 07/16/2020] [Indexed: 02/08/2023] Open
Abstract
Intracellular pathogens mobilize host signaling pathways of their host cell to promote their own survival. Evidence is emerging that signal transduction elements are activated in a-nucleated erythrocytes in response to infection with malaria parasites, but the extent of this phenomenon remains unknown. Here, we fill this knowledge gap through a comprehensive and dynamic assessment of host erythrocyte signaling during infection with Plasmodium falciparum. We used arrays of 878 antibodies directed against human signaling proteins to interrogate the activation status of host erythrocyte phospho-signaling pathways at three blood stages of parasite asexual development. This analysis reveals a dynamic modulation of many host signalling proteins across parasite development. Here we focus on the hepatocyte growth factor receptor (c-MET) and the MAP kinase pathway component B-Raf, providing a proof of concept that human signaling kinases identified as activated by malaria infection represent attractive targets for antimalarial intervention. Plasmodium infection activates signaling pathways in a-nucleated erythrocytes. Here, Adderley et al. use a comprehensive antibody microarray to show that infection extensively modulates host cell signalling and that the host receptor tyrosine kinase c-MET supports Plasmodium falciparum proliferation.
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Affiliation(s)
- Jack D Adderley
- Centre for Chronic Inflammatory and Infectious and Diseases, Biomedical Sciences Cluster, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia
| | - Simona John von Freyend
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Sarah A Jackson
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Megan J Bird
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Amy L Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Burcu Anar
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Tom Metcalf
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Jean-Philippe Semblat
- Institut National de la Transfusion Sanguine, Inserm UMR S1134, 75015, Paris, France
| | - Oliver Billker
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK.,Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, SE-901 87, Sweden
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, 5005, Australia.,Burnet Institute, Melbourne, VIC, 3004, Australia
| | - Christian Doerig
- Centre for Chronic Inflammatory and Infectious and Diseases, Biomedical Sciences Cluster, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia.
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13
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Byerly JH, Port ER, Irie HY. PRKCQ inhibition enhances chemosensitivity of triple-negative breast cancer by regulating Bim. Breast Cancer Res 2020; 22:72. [PMID: 32600444 PMCID: PMC7322866 DOI: 10.1186/s13058-020-01302-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 05/26/2020] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Protein kinase C theta, (PRKCQ/PKCθ) is a serine/threonine kinase that is highly expressed in a subset of triple-negative breast cancers (TNBC) and promotes their growth, anoikis resistance, epithelial-mesenchymal transition (EMT), and invasion. Here, we show that PRKCQ regulates the sensitivity of TNBC cells to apoptosis triggered by standard-of-care chemotherapy by regulating levels of pro-apoptotic Bim. METHODS To determine the effects of PRKCQ expression on chemotherapy-induced apoptosis, shRNA and cDNA vectors were used to modulate the PRKCQ expression in MCF-10A breast epithelial cells or triple-negative breast cancer cells (MDA-MB231Luc, HCC1806). A novel PRKCQ small-molecule inhibitor, 17k, was used to inhibit kinase activity. Viability and apoptosis of cells treated with PRKCQ cDNA/shRNA/inhibitor +/-chemotherapy were measured. Expression levels of Bcl2 family members were assessed. RESULTS Enhanced expression of PRKCQ is sufficient to suppress apoptosis triggered by paclitaxel or doxorubicin treatment. Downregulation of PRKCQ also enhanced the apoptosis of chemotherapy-treated TNBC cells. Regulation of chemotherapy sensitivity by PRKCQ mechanistically occurs via regulation of levels of Bim, a pro-apoptotic Bcl2 family member; suppression of Bim prevents the enhanced apoptosis observed with combined PRKCQ downregulation and chemotherapy treatment. Regulation of Bim and chemotherapy sensitivity is significantly dependent on PRKCQ kinase activity; overexpression of a catalytically inactive PRKCQ does not suppress Bim or chemotherapy-associated apoptosis. Furthermore, PRKCQ kinase inhibitor treatment suppressed growth, increased anoikis and Bim expression, and enhanced apoptosis of chemotherapy-treated TNBC cells, phenocopying the effects of PRKCQ downregulation. CONCLUSIONS These studies support PRKCQ inhibition as an attractive therapeutic strategy and complement to chemotherapy to inhibit the growth and survival of TNBC cells.
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Affiliation(s)
- Jessica H Byerly
- Division of Hematology and Medical Oncology, Department of Medicine, New York, USA
| | - Elisa R Port
- Department of Surgery, Mount Sinai Hospital, New York, NY, 10029, USA
| | - Hanna Y Irie
- Division of Hematology and Medical Oncology, Department of Medicine, New York, USA. .,Department of Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, 1468 Madison Avenue, New York, NY, 10029, USA.
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14
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Han C, Lei D, Liu L, Xie S, He L, Wen S, Zhou H, Ma T, Li S. Morphine induces the differentiation of T helper cells to Th2 effector cells via the PKC-θ-GATA3 pathway. Int Immunopharmacol 2020; 80:106133. [PMID: 31931364 DOI: 10.1016/j.intimp.2019.106133] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/28/2019] [Accepted: 12/12/2019] [Indexed: 11/16/2022]
Abstract
BACKGROUND T help 2 (Th2) cell differentiation by morphine has been verified. However, the underlying mechanism of morphine induces Th2 cell differentiation remains elusive. The aim of the present study was to explore the possible basis of morphine induced Th2 cell differentiation. METHODS Flow cytometry analysis was used to detect the content of T help 1(Th1) cell and Th2 cell. Enzyme linked immunosorbent assay (ELISA) was performed to determine the levels of IL-4 and IFN-γ. Real-time quantitative polymerase chain reaction, electrophoretic mobility shift assay and Western blotting was conducted in this study. RESULTS Th2 cell subset and IL-4 level were elevated in morphine induced naïve T cells. Pathway determining found the protein phosphorylation level of PKC-θ and the expression and activity of the transcription factor GATA3 was also enhanced in the naïve T cells challenged by morphine. Moreover, inhibitor of morphine(naltrexone) or PKC-θ(AEB071) can reverse morphine-induced Th2 cell differentiation. CONCLUSION These results suggested that morphine induce naïve T cell differentiation to Th2 cells via the PKC-θ/GATA3 signal pathway.
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Affiliation(s)
- Chao Han
- Department of Anesthesiology, The Affiliated Yixing Hospital of Jiangsu University, Yixing, Jiangsu, China; Yixing Clinical College, Medical College of Yangzhou University, Yixing, Jiangsu, China
| | - Daoyun Lei
- Department of Anesthesiology, The Affiliated Yixing Hospital of Jiangsu University, Yixing, Jiangsu, China
| | - Li Liu
- Department of Anesthesiology, The Affiliated Yixing Hospital of Jiangsu University, Yixing, Jiangsu, China
| | - Songhui Xie
- Department of Anesthesiology, The Affiliated Yixing Hospital of Jiangsu University, Yixing, Jiangsu, China
| | - Lianping He
- School of Experience Industry, Anhui Polytechnic University, Wuhu, Anhui, China
| | - Shuang Wen
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hong Zhou
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Tieliang Ma
- Department of Anesthesiology, The Affiliated Yixing Hospital of Jiangsu University, Yixing, Jiangsu, China; Yixing Clinical College, Medical College of Yangzhou University, Yixing, Jiangsu, China.
| | - Shitong Li
- Department of Anesthesiology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China
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15
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Activation of RSK by phosphomimetic substitution in the activation loop is prevented by structural constraints. Sci Rep 2020; 10:591. [PMID: 31953410 PMCID: PMC6969211 DOI: 10.1038/s41598-019-56937-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 12/19/2019] [Indexed: 11/08/2022] Open
Abstract
The activation of the majority of AGC kinases is regulated by two phosphorylation events on two conserved serine/threonine residues located on the activation loop and on the hydrophobic motif, respectively. In AGC kinase family, phosphomimetic substitutions with aspartate or glutamate, leading to constitutive activation, have frequently occurred at the hydrophobic motif site. On the contrary, phosphomimetic substitutions in the activation loop are absent across the evolution of AGC kinases. This observation is explained by the failure of aspartate and glutamate to mimic phosphorylatable serine/threonine in this regulatory site. By detailed 3D structural simulations of RSK2 and further biochemical evaluation in cells, we show that the phosphomimetic residue on the activation loop fails to form a critical salt bridge with R114, necessary to reorient the αC-helix and to activate the protein. By a phylogenetic analysis, we point at a possible coevolution of a phosphorylatable activation loop and the presence of a conserved positively charged amino acid on the αC-helix. In sum, our analysis leads to the unfeasibility of phosphomimetic substitution in the activation loop of RSK and, at the same time, highlights the peculiar structural role of activation loop phosphorylation.
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16
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Thuille N, Siegmund K, Klepsch V, Schörgenhuber J, Danklmaier S, Leitges M, Baier G. Loss-of-function phenotype of a PKCθ T219A knockin mouse strain. Cell Commun Signal 2019; 17:141. [PMID: 31694643 PMCID: PMC6836476 DOI: 10.1186/s12964-019-0466-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/22/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Protein kinase C θ has been established as an important signaling intermediate in T-effector-cell activation and survival pathways by controlling activity of the key transcription factors NF-κB and NFAT. Previous studies identified an activation-induced auto-phosphorylation site at Thr-219, located between the tandem C1 domains of the regulatory fragment in PKCθ, as a structural requirement for its correct membrane translocation and the subsequent transactivation of downstream signals leading to IL-2 production in a human T cell line. METHODS The present work aimed to define the role of this phosphorylation switch on PKCθ in a physiological context through a homozygous T219A knockin mouse strain. T cell activation was analyzed by H3-thymidine uptake (proliferative response), qRT-PCR and luminex measurements (cytokine production). NFAT and NF-κB transactivation responses were estimated by Gel mobility shift and Alpha Screen assays. Frequencies of T cell subsets were analyzed by flow cytometry. RESULTS Despite a normal T cell development, in vitro activated effector T cells clearly revealed a requirement of Thr-219 phosphorylation site on PKCθ for a transactivation of NF-κB and NFAT transcription factors and, subsequently, robust IL-2 and IFN-γ expression. CONCLUSION This phenotype is reminiscent of the PKCθ knockout T cells, physiologically validating that this (p) Thr-219 auto-phosphorylation site indeed critically regulates PKCθ function in primary mouse T cells.
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Affiliation(s)
- Nikolaus Thuille
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria.
| | - Kerstin Siegmund
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Victoria Klepsch
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria
| | | | - Sarah Danklmaier
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria
| | | | - Gottfried Baier
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria.
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Xie J, Han X, Zhao C, Canonigo-Balancio AJ, Yates JR, Li Y, Lillemeier BF, Altman A. Phosphotyrosine-dependent interaction between the kinases PKCθ and Zap70 promotes proximal TCR signaling. Sci Signal 2019; 12:12/577/eaar3349. [PMID: 30992398 DOI: 10.1126/scisignal.aar3349] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Protein kinase C-θ (PKCθ) is an important component of proximal T cell receptor (TCR) signaling. We previously identified the amino-terminal C2 domain of PKCθ as a phosphotyrosine (pTyr)-binding domain. Using a mutant form of PKCθ that cannot bind pTyr (PKCθHR2A), we showed that pTyr binding by PKCθ was required for TCR-induced T cell activation, proliferation, and TH2 cell differentiation but not for T cell development. Using tandem mass spectrometry and coimmunoprecipitation, we identified the kinase ζ-associated protein kinase of 70 kDa (Zap70) as a binding partner of the PKCθ pTyr-binding pocket. Tyr126 of Zap70 directly bound to PKCθ, and the interdomain B residues Tyr315 and Tyr319 were indirectly required for binding to PKCθ, reflecting their role in promoting the open conformation of Zap70. PKCθHR2A-expressing CD4+ T cells displayed defects not only in known PKCθ-dependent signaling events, such as nuclear factor κB (NF-κB) activation and TH2 cell differentiation, but also in full activation of Zap70 itself and in the activating phosphorylation of linker of activation of T cells (LAT) and phospholipase C-γ1 (PLCγ1), signaling proteins that are traditionally considered to be activated independently of PKC. These findings demonstrate that PKCθ plays an important role in a positive feedback regulatory loop that modulates TCR-proximal signaling and, moreover, provide a mechanistic explanation for earlier reports that documented an important role for PKCθ in T cell Ca2+ signaling. This PKCθ-Zap70 interaction could potentially serve as a promising and highly selective immunosuppressive drug target in autoimmunity and organ transplantation.
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Affiliation(s)
- Jiji Xie
- Division of Cell Biology, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Xuemei Han
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Chensi Zhao
- State Key Laboratory for Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou 510006, China
| | | | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Yingqiu Li
- State Key Laboratory for Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou 510006, China
| | - Björn F Lillemeier
- Nomis Center for Immunobiology and Microbial Pathogenesis & Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Amnon Altman
- Division of Cell Biology, La Jolla Institute for Immunology, La Jolla, CA 92037, USA.
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18
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Abderrahmani A, Yengo L, Caiazzo R, Canouil M, Cauchi S, Raverdy V, Plaisance V, Pawlowski V, Lobbens S, Maillet J, Rolland L, Boutry R, Queniat G, Kwapich M, Tenenbaum M, Bricambert J, Saussenthaler S, Anthony E, Jha P, Derop J, Sand O, Rabearivelo I, Leloire A, Pigeyre M, Daujat-Chavanieu M, Gerbal-Chaloin S, Dayeh T, Lassailly G, Mathurin P, Staels B, Auwerx J, Schürmann A, Postic C, Schafmayer C, Hampe J, Bonnefond A, Pattou F, Froguel P. Increased Hepatic PDGF-AA Signaling Mediates Liver Insulin Resistance in Obesity-Associated Type 2 Diabetes. Diabetes 2018; 67:1310-1321. [PMID: 29728363 DOI: 10.2337/db17-1539] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/26/2018] [Indexed: 12/17/2022]
Abstract
In type 2 diabetes (T2D), hepatic insulin resistance is strongly associated with nonalcoholic fatty liver disease (NAFLD). In this study, we hypothesized that the DNA methylome of livers from patients with T2D compared with livers of individuals with normal plasma glucose levels can unveil some mechanism of hepatic insulin resistance that could link to NAFLD. Using DNA methylome and transcriptome analyses of livers from obese individuals, we found that hypomethylation at a CpG site in PDGFA (encoding platelet-derived growth factor α) and PDGFA overexpression are both associated with increased T2D risk, hyperinsulinemia, increased insulin resistance, and increased steatohepatitis risk. Genetic risk score studies and human cell modeling pointed to a causative effect of high insulin levels on PDGFA CpG site hypomethylation, PDGFA overexpression, and increased PDGF-AA secretion from the liver. We found that PDGF-AA secretion further stimulates its own expression through protein kinase C activity and contributes to insulin resistance through decreased expression of insulin receptor substrate 1 and of insulin receptor. Importantly, hepatocyte insulin sensitivity can be restored by PDGF-AA-blocking antibodies, PDGF receptor inhibitors, and by metformin, opening therapeutic avenues. Therefore, in the liver of obese patients with T2D, the increased PDGF-AA signaling contributes to insulin resistance, opening new therapeutic avenues against T2D and possibly NAFLD.
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Affiliation(s)
- Amar Abderrahmani
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
- Section of Genomics of Common Disease, Department of Medicine, Imperial College London, London, U.K
| | - Loïc Yengo
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Robert Caiazzo
- University Lille, INSERM, CHU Lille, U1190 - European Genomic Institute for Diabetes, Lille, France
| | - Mickaël Canouil
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Stéphane Cauchi
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Violeta Raverdy
- University Lille, INSERM, CHU Lille, U1190 - European Genomic Institute for Diabetes, Lille, France
| | - Valérie Plaisance
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Valérie Pawlowski
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Stéphane Lobbens
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Julie Maillet
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Laure Rolland
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Raphael Boutry
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Gurvan Queniat
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Maxime Kwapich
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Mathie Tenenbaum
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Julien Bricambert
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Sophie Saussenthaler
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, and German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Elodie Anthony
- Inserm U1016, Institut Cochin, Centre National de la Recherche Scientifique UMR 8104, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Pooja Jha
- Laboratory of Integrative Systems Physiology, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Julien Derop
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Olivier Sand
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Iandry Rabearivelo
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Audrey Leloire
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
| | - Marie Pigeyre
- University Lille, INSERM, CHU Lille, U1190 - European Genomic Institute for Diabetes, Lille, France
| | - Martine Daujat-Chavanieu
- INSERM U1183, University Montpellier, Institute for Regenerative Medicine and Biotherapy, CHU Montpellier, France
| | - Sabine Gerbal-Chaloin
- INSERM U1183, University Montpellier, Institute for Regenerative Medicine and Biotherapy, CHU Montpellier, France
| | - Tasnim Dayeh
- Department of Clinical Science, Skane University Hospital Malmö, Malmö, Sweden
| | - Guillaume Lassailly
- University Lille, INSERM, CHU Lille, U995 - Lille Inflammation Research International Center, Lille, France
| | - Philippe Mathurin
- University Lille, INSERM, CHU Lille, U995 - Lille Inflammation Research International Center, Lille, France
| | - Bart Staels
- University Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1011- European Genomic Institute for Diabetes, Lille, France
| | - Johan Auwerx
- Laboratory of Integrative Systems Physiology, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Annette Schürmann
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, and German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Catherine Postic
- Inserm U1016, Institut Cochin, Centre National de la Recherche Scientifique UMR 8104, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Clemens Schafmayer
- Department of Visceral and Thoracic Surgery, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Jochen Hampe
- Medical Department 1, Technische Universität Dresden, Dresden, Germany
| | - Amélie Bonnefond
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
- Section of Genomics of Common Disease, Department of Medicine, Imperial College London, London, U.K
| | - François Pattou
- University Lille, INSERM, CHU Lille, U1190 - European Genomic Institute for Diabetes, Lille, France
| | - Philippe Froguel
- University Lille, Centre National de la Recherche Scientifique, Institut Pasteur de Lille, UMR 8199 - European Genomic Institute for Diabetes, Lille, France
- Section of Genomics of Common Disease, Department of Medicine, Imperial College London, London, U.K
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Liu Z, Khalil RA. Evolving mechanisms of vascular smooth muscle contraction highlight key targets in vascular disease. Biochem Pharmacol 2018; 153:91-122. [PMID: 29452094 PMCID: PMC5959760 DOI: 10.1016/j.bcp.2018.02.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/12/2018] [Indexed: 12/11/2022]
Abstract
Vascular smooth muscle (VSM) plays an important role in the regulation of vascular function. Identifying the mechanisms of VSM contraction has been a major research goal in order to determine the causes of vascular dysfunction and exaggerated vasoconstriction in vascular disease. Major discoveries over several decades have helped to better understand the mechanisms of VSM contraction. Ca2+ has been established as a major regulator of VSM contraction, and its sources, cytosolic levels, homeostatic mechanisms and subcellular distribution have been defined. Biochemical studies have also suggested that stimulation of Gq protein-coupled membrane receptors activates phospholipase C and promotes the hydrolysis of membrane phospholipids into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). IP3 stimulates initial Ca2+ release from the sarcoplasmic reticulum, and is buttressed by Ca2+ influx through voltage-dependent, receptor-operated, transient receptor potential and store-operated channels. In order to prevent large increases in cytosolic Ca2+ concentration ([Ca2+]c), Ca2+ removal mechanisms promote Ca2+ extrusion via the plasmalemmal Ca2+ pump and Na+/Ca2+ exchanger, and Ca2+ uptake by the sarcoplasmic reticulum and mitochondria, and the coordinated activities of these Ca2+ handling mechanisms help to create subplasmalemmal Ca2+ domains. Threshold increases in [Ca2+]c form a Ca2+-calmodulin complex, which activates myosin light chain (MLC) kinase, and causes MLC phosphorylation, actin-myosin interaction, and VSM contraction. Dissociations in the relationships between [Ca2+]c, MLC phosphorylation, and force have suggested additional Ca2+ sensitization mechanisms. DAG activates protein kinase C (PKC) isoforms, which directly or indirectly via mitogen-activated protein kinase phosphorylate the actin-binding proteins calponin and caldesmon and thereby enhance the myofilaments force sensitivity to Ca2+. PKC-mediated phosphorylation of PKC-potentiated phosphatase inhibitor protein-17 (CPI-17), and RhoA-mediated activation of Rho-kinase (ROCK) inhibit MLC phosphatase and in turn increase MLC phosphorylation and VSM contraction. Abnormalities in the Ca2+ handling mechanisms and PKC and ROCK activity have been associated with vascular dysfunction in multiple vascular disorders. Modulators of [Ca2+]c, PKC and ROCK activity could be useful in mitigating the increased vasoconstriction associated with vascular disease.
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Affiliation(s)
- Zhongwei Liu
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Raouf A Khalil
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA.
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20
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Hippocampal Protein Kinase C Signaling Mediates the Short-Term Memory Impairment Induced by Delta9-Tetrahydrocannabinol. Neuropsychopharmacology 2018; 43:1021-1031. [PMID: 28816239 PMCID: PMC5854793 DOI: 10.1038/npp.2017.175] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 08/02/2017] [Accepted: 08/09/2017] [Indexed: 01/17/2023]
Abstract
Cannabis affects cognitive performance through the activation of the endocannabinoid system, and the molecular mechanisms involved in this process are poorly understood. Using the novel object-recognition memory test in mice, we found that the main psychoactive component of cannabis, delta9-tetrahydrocannabinol (THC), alters short-term object-recognition memory specifically involving protein kinase C (PKC)-dependent signaling. Indeed, the systemic or intra-hippocampal pre-treatment with the PKC inhibitors prevented the short-term, but not the long-term, memory impairment induced by THC. In contrast, systemic pre-treatment with mammalian target of rapamycin complex 1 inhibitors, known to block the amnesic-like effects of THC on long-term memory, did not modify such a short-term cognitive deficit. Immunoblot analysis revealed a transient increase in PKC signaling activity in the hippocampus after THC treatment. Thus, THC administration induced the phosphorylation of a specific Ser residue in the hydrophobic-motif at the C-terminal tail of several PKC isoforms. This significant immunoreactive band that paralleled cognitive performance did not match in size with the major PKC isoforms expressed in the hippocampus except for PKCθ. Moreover, THC transiently enhanced the phosphorylation of the postsynaptic calmodulin-binding protein neurogranin in a PKC dependent manner. These data demonstrate that THC alters short-term object-recognition memory through hippocampal PKC/neurogranin signaling.
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21
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Hage-Sleiman R, Hamze AB, El-Hed AF, Attieh R, Kozhaya L, Kabbani S, Dbaibo G. Ceramide inhibits PKCθ by regulating its phosphorylation and translocation to lipid rafts in Jurkat cells. Immunol Res 2017; 64:869-86. [PMID: 26798039 DOI: 10.1007/s12026-016-8787-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Protein kinase C theta (PKCθ) is a novel, calcium-independent member of the PKC family of kinases that was identified as a central player in T cell signaling and proliferation. Upon T cell activation by antigen-presenting cells, PKCθ gets phosphorylated and activated prior to its translocation to the immunological synapse where it couples with downstream effectors. PKCθ may be regulated by ceramide, a crucial sphingolipid that is known to promote differentiation, growth arrest, and apoptosis. To further investigate the mechanism, we stimulated human Jurkat T cells with either PMA or anti-CD3/anti-CD28 antibodies following induction of ceramide accumulation by adding exogenous ceramide, bacterial sphingomyelinase, or Fas ligation. Our results suggest that ceramide regulates the PKCθ pathway through preventing its critical threonine 538 (Thr538) phosphorylation and subsequent activation, thereby inhibiting the kinase's translocation to lipid rafts. Moreover, this inhibition is not likely to be a generic effect of ceramide on membrane reorganization. Other lipids, namely dihydroceramide, palmitate, and sphingosine, did not produce similar effects on PKCθ. Addition of the phosphatase inhibitors okadaic acid and calyculin A reversed the inhibition exerted by ceramide, and this suggests involvement of a ceramide-activated protein phosphatase. Such previously undescribed mechanism of regulation of PKCθ raises the possibility that ceramide, or one of its derivatives, and may prove valuable in novel therapeutic approaches for disorders involving autoimmunity or excessive inflammation-where PKCθ plays a critical role.
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Affiliation(s)
- Rouba Hage-Sleiman
- Department of Biology, Faculty of Sciences, Lebanese University, Hadath, Lebanon
| | - Asmaa B Hamze
- Department of Biomedical Science, Faculty of Health Sciences, Global University, Batrakiyye, Beirut, Lebanon
| | - Aimée F El-Hed
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon
| | - Randa Attieh
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon
| | - Lina Kozhaya
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon
| | - Sarah Kabbani
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon
| | - Ghassan Dbaibo
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon.
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Abstract
Protein and lipid kinases are deregulated in most, if not all, cancers and are among the most valuable therapeutic targets in these diseases. Despite the introduction of dozens of effective kinase inhibitors into clinical practice, the development of drug resistance remains a major barrier to treatment because of adaption of cellular signaling pathways to bypass targeted kinases. So that the basal and adaptive responses of kinases in cancer can be better understood, new methods have emerged that allow simultaneous and unbiased measurement of the activation state of a substantial fraction of the entire kinome. Here, we discuss such kinome-profiling methodologies, emphasizing the relative strengths and weaknesses of each approach.
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Affiliation(s)
- Maria Radu
- Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA, 19111-2497, USA
| | - Jonathan Chernoff
- Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA, 19111-2497, USA
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Misuth M, Joniova J, Belej D, Hrivnak S, Horvath D, Huntosova V. Estimation of PKCδ autophosphorylation in U87 MG glioma cells: combination of experimental, conceptual and numerical approaches. JOURNAL OF BIOPHOTONICS 2017; 10:423-432. [PMID: 27158772 DOI: 10.1002/jbio.201500332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/23/2016] [Accepted: 04/03/2016] [Indexed: 06/05/2023]
Abstract
Golgi apparatus (GA) is a center for lipid metabolism and the final target of ceramide pathway, which may result in apoptosis. In this work localization of highly hydrophobic hypericin is followed by time-resolved imaging of NBDC6 (fluorescent ceramide) in U87 MG glioma cells. Decrease of NBDC6 fluorescence lifetimes in cells indicates that hypericin can also follow this pathway. It is known that both, ceramide and hypericin can significantly influence protein kinase C (PKC) activity. Western blotting analysis shows increase of PKCδ autophosphorylation at Ser645 (p(S645)PKCδ) in glioma cells incubated with 500 nM hypericin and confocal-fluorescence microscopy distinguishes p(S645)PKCδ localization between GA related compartments and nucleus. Experimental and numerical methods are combined to study p(S645)PKCδ in U87 MG cell line. Image processing based on conceptual qualitative description is combined with numerical treatment via simple exponential saturation model which describes redistribution of p(S645)PKCδ between nucleus and GA related compartments after hypericin administration. These results suggest, that numerical methods can significantly improve quantification of biomacromolecules (p(S645)PKCδ) directly from the fluorescence images and such obtained outputs are complementary if not equal to typical used methods in biology.
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Affiliation(s)
- Matus Misuth
- Department of Biophysics, Faculty of Science, P.J. Safarik University (UPJS) in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Jaroslava Joniova
- Department of Biophysics, Faculty of Science, P.J. Safarik University (UPJS) in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
- Laboratory of Organometallic and Medicinal Chemistry, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology in Lausanne (EPFL), Station 6, Batiment de Chimie, CH-1015, Lausanne, Switzerland
| | - Dominik Belej
- Department of Biophysics, Faculty of Science, P.J. Safarik University (UPJS) in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Stanislav Hrivnak
- Department of Biophysics, Faculty of Science, P.J. Safarik University (UPJS) in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Denis Horvath
- Center for Interdisciplinary Biosciences, Faculty of Science, P.J. Safarik University (UPJS) in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Veronika Huntosova
- Center for Interdisciplinary Biosciences, Faculty of Science, P.J. Safarik University (UPJS) in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
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24
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Ringvold HC, Khalil RA. Protein Kinase C as Regulator of Vascular Smooth Muscle Function and Potential Target in Vascular Disorders. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:203-301. [PMID: 28212798 PMCID: PMC5319769 DOI: 10.1016/bs.apha.2016.06.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Vascular smooth muscle (VSM) plays an important role in maintaining vascular tone. In addition to Ca2+-dependent myosin light chain (MLC) phosphorylation, protein kinase C (PKC) is a major regulator of VSM function. PKC is a family of conventional Ca2+-dependent α, β, and γ, novel Ca2+-independent δ, ɛ, θ, and η, and atypical ξ, and ι/λ isoforms. Inactive PKC is mainly cytosolic, and upon activation it undergoes phosphorylation, maturation, and translocation to the surface membrane, the nucleus, endoplasmic reticulum, and other cell organelles; a process facilitated by scaffold proteins such as RACKs. Activated PKC phosphorylates different substrates including ion channels, pumps, and nuclear proteins. PKC also phosphorylates CPI-17 leading to inhibition of MLC phosphatase, increased MLC phosphorylation, and enhanced VSM contraction. PKC could also initiate a cascade of protein kinases leading to phosphorylation of the actin-binding proteins calponin and caldesmon, increased actin-myosin interaction, and VSM contraction. Increased PKC activity has been associated with vascular disorders including ischemia-reperfusion injury, coronary artery disease, hypertension, and diabetic vasculopathy. PKC inhibitors could test the role of PKC in different systems and could reduce PKC hyperactivity in vascular disorders. First-generation PKC inhibitors such as staurosporine and chelerythrine are not very specific. Isoform-specific PKC inhibitors such as ruboxistaurin have been tested in clinical trials. Target delivery of PKC pseudosubstrate inhibitory peptides and PKC siRNA may be useful in localized vascular disease. Further studies of PKC and its role in VSM should help design isoform-specific PKC modulators that are experimentally potent and clinically safe to target PKC in vascular disease.
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Affiliation(s)
- H C Ringvold
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - R A Khalil
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
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25
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Affiliation(s)
- Amnon Altman
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037; ,
| | - Kok-Fai Kong
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037; ,
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26
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López-Huertas MR, Li J, Zafar A, Rodríguez-Mora S, García-Domínguez C, Mateos E, Alcamí J, Rao S, Coiras M. PKCθ and HIV-1 Transcriptional Regulator Tat Co-exist at the LTR Promoter in CD4(+) T Cells. Front Immunol 2016; 7:69. [PMID: 26973648 PMCID: PMC4770193 DOI: 10.3389/fimmu.2016.00069] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 02/15/2016] [Indexed: 11/17/2022] Open
Abstract
PKCθ is essential for the activation of CD4+ T cells. Upon TCR/CD28 stimulation, PKCθ is phosphorylated and migrates to the immunological synapse, inducing the activation of cellular transcription factors such as NF-κB and kinases as ERK that are critical for HIV-1 replication. We previously demonstrated that PKCθ is also necessary for HIV-1 replication but the precise mechanism is unknown. Efficient HIV-1 transcription and elongation are absolutely dependent on the synergy between NF-κB and the viral regulator Tat. Tat exerts its function by binding a RNA stem-loop structure proximal to the viral mRNA cap site termed TAR. Besides, due to its effect on cellular metabolic pathways, Tat causes profound changes in infected CD4+ T cells such as the activation of NF-κB and ERK. We hypothesized that the aberrant upregulation of Tat-mediated activation of NF-κB and ERK occurred through PKCθ signaling. In fact, Jurkat TetOff cells with stable and doxycycline-repressible expression of Tat (Jurkat-Tat) expressed high levels of mRNA for PKCθ. In these cells, PKCθ located at the plasma membrane was phosphorylated at T538 residue in undivided cells, in the absence of stimulation. Treatment with doxycycline inhibited PKCθ phosphorylation in Jurkat-Tat, suggesting that Tat expression was directly related to the activation of PKCθ. Both NF-κB and Ras/Raf/MEK/ERK signaling pathway were significantly activated in Jurkat-Tat cells, and this correlated with high transactivation of HIV-1 LTR promoter. RNA interference for PKCθ inhibited NF-κB and ERK activity, as well as LTR-mediated transactivation even in the presence of Tat. In addition to Tat-mediated activation of PKCθ in the cytosol, we demonstrated by sequential ChIP that Tat and PKCθ coexisted in the same complex bound at the HIV-1 LTR promoter, specifically at the region containing TAR loop. In conclusion, PKCθ-Tat interaction seemed to be essential for HIV-1 replication in CD4+ T cells and could be used as a therapeutic target.
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Affiliation(s)
- María Rosa López-Huertas
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - Jasmine Li
- Department of Microbiology and Immunology, The Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne, VIC , Australia
| | - Anjum Zafar
- Biomedical Sciences, Faculty of Education, Science, Technology and Mathematics, University of Canberra , Canberra, ACT , Australia
| | - Sara Rodríguez-Mora
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - Carlota García-Domínguez
- Functional Research Unit in Chronic Diseases, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - Elena Mateos
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - José Alcamí
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
| | - Sudha Rao
- Biomedical Sciences, Faculty of Education, Science, Technology and Mathematics, University of Canberra , Canberra, ACT , Australia
| | - Mayte Coiras
- AIDS Immunopathology Unit, National Center of Microbiology, Instituto de Salud Carlos III , Madrid , Spain
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27
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Lai S, Pelech S. Regulatory roles of conserved phosphorylation sites in the activation T-loop of the MAP kinase ERK1. Mol Biol Cell 2016; 27:1040-50. [PMID: 26823016 PMCID: PMC4791125 DOI: 10.1091/mbc.e15-07-0527] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 01/20/2016] [Indexed: 02/05/2023] Open
Abstract
The catalytic domains of most eukaryotic protein kinases are highly conserved in their primary structures. Their phosphorylation within the well-known activation T-loop, a variable region between protein kinase catalytic subdomains VII and VIII, is a common mechanism for stimulation of their phosphotransferase activities. Extracellular signal-regulated kinase 1 (ERK1), a member of the extensively studied mitogen-activated protein kinase (MAPK) family, serves as a paradigm for regulation of protein kinases in signaling modules. In addition to the well-documented T202 and Y204 stimulatory phosphorylation sites in the activation T-loop of ERK1 and its closest relative, ERK2, three additional flanking phosphosites have been confirmed (T198, T207, and Y210 from ERK1) by high-throughput mass spectrometry. In vitro kinase assays revealed the functional importance of T207 and Y210, but not T198, in negatively regulating ERK1 catalytic activity. The Y210 site could be important for proper conformational arrangement of the active site, and a Y210F mutant could not be recognized by MEK1 for phosphorylation of T202 and Y204 in vitro. Autophosphorylation of T207 reduces the catalytic activity and stability of activated ERK1. We propose that after the activation of ERK1 by MEK1, subsequent slower phosphorylation of the flanking sites results in inhibition of the kinase. Because the T207 and Y210 phosphosites of ERK1 are highly conserved within the eukaryotic protein kinase family, hyperphosphorylation within the kinase activation T-loop may serve as a general mechanism for protein kinase down-regulation after initial activation by their upstream kinases.
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Affiliation(s)
- Shenshen Lai
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Steven Pelech
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC V6T 2B5, Canada Kinexus Bioinformatics Corporation, Vancouver, BC V6P 6T3, Canada
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Zaid Y, Senhaji N, Naya A, Fadainia C, Kojok K. PKCs in thrombus formation. ACTA ACUST UNITED AC 2015; 63:268-71. [PMID: 26476932 DOI: 10.1016/j.patbio.2015.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 09/01/2015] [Indexed: 10/22/2022]
Abstract
The protein kinase C (PKC) family has been implicated in several physiological processes regulating platelet activation. Each isoform of PKC expressed on platelets, may have a positive and/or negative role depending on the nature and concentration of the agonist. Mice lacking PKCα show much reduced thrombus formation in vivo, while PKCθ(-/-) showed inhibition of aggregation in response to PAR4. On the other hand, PKCδ by associating with Fyn, inhibits platelet aggregation. In addition, PKCβ by interacting with its receptor RACK1 has been implicated in the primary phases of signaling via the αIIbβ3 and finally PKCɛ appears to be involved in platelet function downstream GPVI. The present review discusses the latest observations relevant to the role of individual PKC isoforms in platelet activation and thrombus formation.
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Affiliation(s)
- Y Zaid
- Laboratory of Thrombosis and Hemostasis, Montreal Heart Institute, 5000 Belanger, Montreal, H1T 1C8 Quebec, Canada.
| | - N Senhaji
- Laboratory of Genetic and Molecular Pathology (LGPM), Medical School, Hassan II University, Casablanca, Morocco
| | - A Naya
- Laboratory of Physiology and Molecular Genetic, Faculty of Sciences, Hassan II University, Casablanca, Morocco
| | - C Fadainia
- Laboratory of Thrombosis and Hemostasis, Montreal Heart Institute, 5000 Belanger, Montreal, H1T 1C8 Quebec, Canada
| | - K Kojok
- Laboratory of Thrombosis and Hemostasis, Montreal Heart Institute, 5000 Belanger, Montreal, H1T 1C8 Quebec, Canada
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29
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Brezar V, Tu WJ, Seddiki N. PKC-Theta in Regulatory and Effector T-cell Functions. Front Immunol 2015; 6:530. [PMID: 26528291 PMCID: PMC4602307 DOI: 10.3389/fimmu.2015.00530] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 09/28/2015] [Indexed: 01/20/2023] Open
Abstract
One of the major goals in immunology research is to understand the regulatory mechanisms that underpin the rapid switch on/off of robust and efficient effector (Teffs) or regulatory (Tregs) T-cell responses. Understanding the molecular mechanisms underlying the regulation of such responses is critical for the development of effective therapies. T-cell activation involves the engagement of T-cell receptor and co-stimulatory signals, but the subsequent recruitment of serine/threonine-specific protein Kinase C-theta (PKC-θ) to the immunological synapse (IS) is instrumental for the formation of signaling complexes, which ultimately lead to a transcriptional network in T cells. Recent studies demonstrated that major differences between Teffs and Tregs occurred at the IS where its formation induces altered signaling pathways in Tregs. These pathways are characterized by reduced recruitment of PKC-θ, suggesting that PKC-θ inhibits Tregs suppressive function in a negative feedback loop. As the balance of Teffs and Tregs has been shown to be central in several diseases, it was not surprising that some studies revealed that PKC-θ plays a major role in the regulation of this balance. This review will examine recent knowledge on the role of PKC-θ in T-cell transcriptional responses and how this protein can impact on the function of both Tregs and Teffs.
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Affiliation(s)
- Vedran Brezar
- INSERM U955, Équipe 16 and Faculté de Médecine, Université Paris Est , Créteil , France ; Vaccine Research Institute (VRI) , Créteil , France
| | - Wen Juan Tu
- Faculty of Education, Science, Technology and Maths, University of Canberra , Canberra, ACT , Australia
| | - Nabila Seddiki
- INSERM U955, Équipe 16 and Faculté de Médecine, Université Paris Est , Créteil , France ; Vaccine Research Institute (VRI) , Créteil , France
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30
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Abstract
The protein kinases C (PKCs) are a family of serine/threonine kinases involved in regulating multiple essential cellular processes such as survival, proliferation, and differentiation. Of particular interest is the novel, calcium-independent PKCθ which plays a central role in immune responses. PKCθ shares structural similarities with other PKC family members, mainly consisting of an N-terminal regulatory domain and a C-terminal catalytic domain tethered by a hinge region. This isozyme, however, is unique in that it translocates to the immunological synapse between a T cell and an antigen-presenting cell (APC) upon T cell receptor-peptide MHC recognition. Thereafter, PKCθ interacts physically and functionally with downstream effectors to mediate T cell activation and differentiation, subsequently leading to inflammation. PKCθ-specific perturbations have been identified in several diseases, most notably autoimmune disorders, and hence the modulation of its activity presents an attractive therapeutic intervention. To that end, many inhibitors of PKCs and PKCθ have been developed and tested in preclinical and clinical studies. And although selectivity remains a challenge, results are promising for the future development of effective PKCθ inhibitors that would greatly advance the treatment of several T-cell mediated diseases.
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31
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Gorelik G, Sawalha AH, Patel D, Johnson K, Richardson B. T cell PKCδ kinase inactivation induces lupus-like autoimmunity in mice. Clin Immunol 2015; 158:193-203. [PMID: 25829232 DOI: 10.1016/j.clim.2015.03.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 03/05/2015] [Accepted: 03/06/2015] [Indexed: 12/12/2022]
Abstract
Genetic and environmental factors contribute to the onset and progression of lupus. CD4+ T cells from patients with active lupus show a decreased ERK signaling pathway, which causes changes in gene expression. The defect points to its upstream regulator, PKCδ, which exhibits a deficient activity due to oxidative stress. Our aim was to investigate the effect of a defective PKCδ in the development of lupus. We generated a double transgenic C57BL6 × SJL mouse that expresses a doxycycline-induced dominant negative PKCδ (dnPKCδ) in T cells. The transgenic mice displayed decreased T cell ERK signaling, decreased DNMT1 expression and overexpression of methylation sensitive genes involved in the exaggerated immune response in the pathogenesis of lupus. The mice developed anti-dsDNA autoantibodies and glomerulonephritis with IgG deposition. The study indicates common pathogenic mechanisms with human lupus, suggesting that environmentally-mediated T cell PKCδ inactivation plays a causative role in lupus.
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Affiliation(s)
- Gabriela Gorelik
- Department of Medicine, University of Michigan, Ann Arbor, MI, USA.
| | - Amr H Sawalha
- Department of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Dipak Patel
- Department of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Kent Johnson
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Bruce Richardson
- Department of Medicine, University of Michigan, Ann Arbor, MI, USA; Ann Arbor VA Medical Center, Ann Arbor, MI, USA
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Martin-Liberal J, Cameron AJ, Claus J, Judson IR, Parker PJ, Linch M. Targeting protein kinase C in sarcoma. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1846:547-59. [PMID: 25453364 DOI: 10.1016/j.bbcan.2014.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/19/2014] [Accepted: 10/08/2014] [Indexed: 12/14/2022]
Abstract
Protein kinase C (PKC) is a family of serine/threonine tyrosine kinases that regulate many cellular processes including division, proliferation, survival, anoikis and polarity. PKC is abundant in many human cancers and aberrant PKC signalling has been demonstrated in cancer models. On this basis, PKC has become an attractive target for small molecule inhibition within oncology drug development programmes. Sarcoma is a heterogeneous group of mesenchymal malignancies. Due to their relative insensitivity to conventional chemotherapies and the increasing recognition of the driving molecular events of sarcomagenesis, sarcoma provides an excellent platform to test novel therapeutics. In this review we provide a structure-function overview of the PKC family, the rationale for targeting these kinases in sarcoma and the state of play with regard to PKC inhibition in the clinic.
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Affiliation(s)
- J Martin-Liberal
- Sarcoma Unit, Royal Marsden Hospital, Fulham Road, London SW3 6JJ, UK
| | - A J Cameron
- Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - J Claus
- Protein Phosphorylation Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - I R Judson
- Sarcoma Unit, Royal Marsden Hospital, Fulham Road, London SW3 6JJ, UK
| | - P J Parker
- Protein Phosphorylation Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3LY, UK; Division of Cancer Studies, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - M Linch
- Department of Oncology, University College London Cancer Institute, London, UK.
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Martin-Blanco NM, Checquolo S, Del Gaudio F, Palermo R, Franciosa G, Di Marcotullio L, Gulino A, Canelles M, Screpanti I. Numb-dependent integration of pre-TCR and p53 function in T-cell precursor development. Cell Death Dis 2014; 5:e1472. [PMID: 25321479 PMCID: PMC4237259 DOI: 10.1038/cddis.2014.438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/30/2014] [Accepted: 09/02/2014] [Indexed: 11/09/2022]
Abstract
Numb asymmetrically segregates at mitosis to control cell fate choices during development. Numb inheritance specifies progenitor over differentiated cell fates, and, paradoxically, also promotes neuronal differentiation, thus indicating that the role of Numb may change during development. Here we report that Numb nuclear localization is restricted to early thymocyte precursors, whereas timed appearance of pre-T-cell receptor (pre-TCR) and activation of protein kinase Cθ promote phosphorylation-dependent Numb nuclear exclusion. Notably, nuclear localization of Numb in early thymocyte precursors favors p53 nuclear stabilization, whereas pre-TCR-dependent Numb nuclear exclusion promotes the p53 downmodulation essential for further differentiation. Accordingly, the persistence of Numb in the nucleus impairs the differentiation and promotes precursor cell death. This study reveals a novel regulatory mechanism for Numb function based on its nucleus–cytosol shuttling, coupling the different roles of Numb with different stages of T-cell development.
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Affiliation(s)
- N M Martin-Blanco
- Department of Molecular Medicine, Sapienza University, 00161 Rome, Italy
| | - S Checquolo
- Department of Medico-Surgical Sciences and Biotechnology, Sapienza University, Latina 04100, Italy
| | - F Del Gaudio
- Department of Molecular Medicine, Sapienza University, 00161 Rome, Italy
| | - R Palermo
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome 00161, Italy
| | - G Franciosa
- Department of Molecular Medicine, Sapienza University, 00161 Rome, Italy
| | - L Di Marcotullio
- Department of Molecular Medicine, Sapienza University, 00161 Rome, Italy
| | - A Gulino
- 1] Department of Molecular Medicine, Sapienza University, 00161 Rome, Italy [2] Neuromed Institute, Pozzilli 86007, Italy
| | - M Canelles
- Institute of Parasitology and Biomedicine 'Lopez Neyra', Spanish National Research Council, Granada 18100, Spain
| | - I Screpanti
- 1] Department of Molecular Medicine, Sapienza University, 00161 Rome, Italy [2] Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome 00161, Italy [3] Institut Pasteur-Foundation Cenci Bolognetti, Sapienza University, Rome 00161, Italy
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Dieni CA, Storey KB. Protein kinase C in the wood frog, Rana sylvatica: reassessing the tissue-specific regulation of PKC isozymes during freezing. PeerJ 2014; 2:e558. [PMID: 25210662 PMCID: PMC4157297 DOI: 10.7717/peerj.558] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 08/14/2014] [Indexed: 01/03/2023] Open
Abstract
The wood frog, Rana sylvatica, survives whole-body freezing and thawing each winter. The extensive adaptations required at the biochemical level are facilitated by alterations to signaling pathways, including the insulin/Akt and AMPK pathways. Past studies investigating changing tissue-specific patterns of the second messenger IP3 in adapted frogs have suggested important roles for protein kinase C (PKC) in response to stress. In addition to their dependence on second messengers, phosphorylation of three PKC sites by upstream kinases (most notably PDK1) is needed for full PKC activation, according to widely-accepted models. The present study uses phospho-specific immunoblotting to investigate phosphorylation states of PKC—as they relate to distinct tissues, PKC isozymes, and phosphorylation sites—in control and frozen frogs. In contrast to past studies where second messengers of PKC increased during the freezing process, phosphorylation of PKC tended to generally decline in most tissues of frozen frogs. All PKC isozymes and specific phosphorylation sites detected by immunoblotting decreased in phosphorylation levels in hind leg skeletal muscle and hearts of frozen frogs. Most PKC isozymes and specific phosphorylation sites detected in livers and kidneys also declined; the only exceptions were the levels of isozymes/phosphorylation sites detected by the phospho-PKCα/βII (Thr638/641) antibody, which remained unchanged from control to frozen frogs. Changes in brains of frozen frogs were unique; no decreases were observed in the phosphorylation levels of any of the PKC isozymes and/or specific phosphorylation sites detected by immunoblotting. Rather, increases were observed for the levels of isozymes/phosphorylation sites detected by the phospho-PKCα/βII (Thr638/641), phospho-PKCδ (Thr505), and phospho-PKCθ (Thr538) antibodies; all other isozymes/phosphorylation sites detected in brain remained unchanged from control to frozen frogs. The results of this study indicate a potential important role for PKC in cerebral protection during wood frog freezing. Our findings also call for a reassessment of the previously-inferred importance of PKC in other tissues, particularly in liver; a more thorough investigation is required to determine whether PKC activity in this physiological situation is indeed dependent on phosphorylation, or whether it deviates from the generally-accepted model and can be “overridden” by exceedingly high levels of second messengers, as has been demonstrated with certain PKC isozymes (e.g., PKCδ).
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Affiliation(s)
| | - Kenneth B Storey
- Institute of Biochemistry, Carleton University , Ottawa, Ontario , Canada
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Rozenberg K, Smirin P, Sampson SR, Rosenzweig T. Insulin-sensitizing and insulin-mimetic activities of Sarcopoterium spinosum extract. JOURNAL OF ETHNOPHARMACOLOGY 2014; 155:362-372. [PMID: 24882728 DOI: 10.1016/j.jep.2014.05.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/13/2014] [Accepted: 05/07/2014] [Indexed: 06/03/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Sarcopoterium spinosum is an abundant plant in Israel, used by Bedouin medicinal practitioners for the treatment of diabetes. In our previous study we validated the anti-diabetic activity of Sarcopoterium spinosum. The aim of this study was to further clarify its mechanism of action. MATERIALS AND METHODS In-vivo studies were performed on KK-a/y mice given the extract for 6 weeks. Insulin tolerance test was performed, and relative pancreatic islets area was measured. Mechanisms of action were investigated in L6 myotubes using protein array, Western blot analysis and confocal microscopy. Glucose uptake assays were performed in 3T3-L1 adipocytes. RESULTS Sarcopoterium spinosum extract reduced fasting blood glucose and improved insulin sensitivity in treated mice. Hypertrophic islets were detected in diabetic, but not in Sarcopoterium spinosum-treated mice. Sarcopoterium spinosum phosphorylated PTEN on ser380 and thr382/383, which are known inhibitory sites. PKB was not phosphorylated by Sarcopoterium spinosum, however, translocation of PKB from cytoplasm to the membrane and nucleus was detected. Target proteins of PKB were regulated by Sarcopoterium spinosum; GSK3β was phosphorylated and cytosolic localization of FoxO was increased. Glucose uptake was increased in a PI3K and AMPK-independent mechanism. CONCLUSIONS We suggest that Sarcopoterium spinosum inhibited PTEN and activated PKB by a mechanism which is independent of ser473 and thr308 phosphorylation. Other post translation modifications might be involved and should be analyzed further in order to understand this unique PKB activation. Identifying the active molecules in the extract, may lead to the development of new agents for the treatment of insulin resistance.
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Affiliation(s)
- Konstantin Rozenberg
- Departments of Molecular Biology and Nutrition, Ariel University, Ariel 40700, Israel; Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Polina Smirin
- Departments of Molecular Biology and Nutrition, Ariel University, Ariel 40700, Israel; Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Sanford R Sampson
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel; Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76101, Israel
| | - Tovit Rosenzweig
- Departments of Molecular Biology and Nutrition, Ariel University, Ariel 40700, Israel; Samaria and Jordan Rift R&D Center, Ariel 40700, Israel.
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Kim HR, Gallant C, Morgan KG. Regulation of PKC autophosphorylation by calponin in contractile vascular smooth muscle tissue. BIOMED RESEARCH INTERNATIONAL 2013; 2013:358643. [PMID: 24350264 PMCID: PMC3852320 DOI: 10.1155/2013/358643] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/10/2013] [Accepted: 10/24/2013] [Indexed: 01/31/2023]
Abstract
Protein kinase C (PKC) is a key enzyme involved in agonist-induced smooth muscle contraction. In some cases, regulatory phosphorylation of PKC is required for full activation of the enzyme. However, this issue has largely been ignored with respect to PKC-dependent regulation of contractile vascular smooth muscle (VSM) contractility. The first event in PKC regulation is a transphosphorylation by PDK at a conserved threonine in the activation loop of PKC, followed by the subsequent autophosphorylation at the turn motif and hydrophobic motif sites. In the present study, we determined whether phosphorylation of PKC is a regulated process in VSM and also investigated a potential role of calponin in the regulation of PKC. We found that calponin increases the level of in vitro PKCα phosphorylation at the PDK and hydrophobic sites, but not the turn motif site. In vascular tissues, phosphorylation of the PKC hydrophobic site, but not turn motif site, as well as phosphorylation of PDK at S241 increased in response to phenylephrine. Calponin knockdown inhibits autophosphorylation of cellular PKC in response to phenylephrine, confirming results with recombinant PKC. Thus these results show that autophosphorylation of PKC is regulated in dVSM and calponin is necessary for autophosphorylation of PKC in VSM.
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Affiliation(s)
- Hak Rim Kim
- Department of Health Sciences, Boston University, 635 Commonwealth Avenue, Boston, MA 02215, USA
- Department of Pharmacology, College of Medicine, Dankook University, 119 Dandaero, Chungnam, Cheonan-si 330-714, Republic of Korea
| | - Cynthia Gallant
- Department of Health Sciences, Boston University, 635 Commonwealth Avenue, Boston, MA 02215, USA
| | - Kathleen G. Morgan
- Department of Health Sciences, Boston University, 635 Commonwealth Avenue, Boston, MA 02215, USA
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Cannon JL, Asperti-Boursin F, Letendre KA, Brown IK, Korzekwa KE, Blaine KM, Oruganti SR, Sperling AI, Moses ME. PKCθ regulates T cell motility via ezrin-radixin-moesin localization to the uropod. PLoS One 2013; 8:e78940. [PMID: 24250818 PMCID: PMC3826749 DOI: 10.1371/journal.pone.0078940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 09/17/2013] [Indexed: 01/05/2023] Open
Abstract
Cell motility is a fundamental process crucial for function in many cell types, including T cells. T cell motility is critical for T cell-mediated immune responses, including initiation, activation, and effector function. While many extracellular receptors and cytoskeletal regulators have been shown to control T cell migration, relatively few signaling mediators have been identified that can modulate T cell motility. In this study, we find a previously unknown role for PKCθ in regulating T cell migration to lymph nodes. PKCθ localizes to the migrating T cell uropod and regulates localization of the MTOC, CD43 and ERM proteins to the uropod. Furthermore, PKCθ-deficient T cells are less responsive to chemokine induced migration and are defective in migration to lymph nodes. Our results reveal a novel role for PKCθ in regulating T cell migration and demonstrate that PKCθ signals downstream of CCR7 to regulate protein localization and uropod formation.
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Affiliation(s)
- Judy L. Cannon
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
- * E-mail:
| | - Francois Asperti-Boursin
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
- Department of Computer Science, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Kenneth A. Letendre
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
- Department of Computer Science, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Ivy K. Brown
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Katy E. Korzekwa
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Kelly M. Blaine
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Sreenivasa R. Oruganti
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Anne I. Sperling
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Melanie E. Moses
- Department of Computer Science, University of New Mexico, Albuquerque, New Mexico, United States of America
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Very large G protein-coupled receptor 1 regulates myelin-associated glycoprotein via Gαs/Gαq-mediated protein kinases A/C. Proc Natl Acad Sci U S A 2013; 110:19101-6. [PMID: 24191038 DOI: 10.1073/pnas.1318501110] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
VLGR1 (very large G protein-coupled receptor 1), also known as MASS1 (monogenic audiogenic seizure susceptible 1), is an orphan G protein-coupled receptor that contains a large extracellular N terminus with 35 calcium-binding domains. A truncating mutation in the Mass1 gene causes autosomal recessive, sound-induced seizures in the Frings mouse. However, the function of MASS1 and the mechanism underlying Frings mouse epilepsy are not known. Here, we found that MASS1 protein is enriched in the myelinated regions of the superior and inferior colliculi, critical areas for the initiation and propagation of audiogenic seizures. Using a panel of myelin antibodies, we discovered that myelin-associated glycoprotein (MAG) expression is dramatically decreased in Frings mice. MASS1 inhibits the ubiquitylation of MAG, thus enhancing the stability of this protein, and the calcium-binding domains of MASS1 are essential for this regulation. Furthermore, MASS1 interacts with Gαs/Gαq and activates PKA and PKC in response to extracellular calcium. Suppression of signaling by MASS1 RNAi or a specific inhibitor abrogates MAG up-regulation. We postulate that MASS1 senses extracellular calcium and activates cytosolic PKA/PKC pathways to regulate myelination by means of MAG protein stability in myelin-forming cells of the auditory pathway. Further work is required to determine whether MAG dysregulation is a cause or consequence of audiogenic epilepsy and whether there are other pathways regulated by MASS1.
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Na BR, Kim HR, Kwon MS, Lee HS, Piragyte I, Choi EJ, Choi HK, Han WC, Lee SH, Jun CD. Aplotaxene blocks T cell activation by modulation of protein kinase C-θ-dependent pathway. Food Chem Toxicol 2013; 62:23-31. [PMID: 23941771 DOI: 10.1016/j.fct.2013.08.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 07/15/2013] [Accepted: 08/07/2013] [Indexed: 12/12/2022]
Abstract
Aplotaxene, (8Z, 11Z, 14Z)-heptadeca-1, 8, 11, 14-tetraene, is one of the major components of essential oil obtained from Inula helenium root, which is used in Oriental medicine. However, the effects of aplotaxene on immunity have not been investigated. Here, we show that aplotaxene inhibits T cell activation in terms of IL-2 and CD69 expression. Aplotaxene, at a concentration that optimally inhibits IL-2 production, has little effect on apoptotic or necrotic cell death, suggesting that apoptosis is not a mechanism for aplotaxene-mediated inhibition of T cell activation. Aplotaxene affects neither superantigeninduced conjugate formation between Jurkat T cells and Raji B cells nor clustering of CD3 and LFA-1 at the immunological synapse. Aplotaxene significantly inhibits PKC-θ phosphorylation and translocation to the immunological synapse, and blocks PMA-induced T-cell receptor internalization. Furthermore, aplotaxene leads to inhibition of mitogen-activated protein kinases (JNK, ERK and p38) phosphorylation and NF-κB, NF-AT, and AP-1 promoter activities in Jurkat T cells. Taken together, our findings provide evidence for the immunosuppressive effect of aplotaxene on activated T cells through the modulation of the PKC-θ and MAPK pathways, suggesting that aplotaxene may be a novel immunotherapeutic agent for immunological diseases related to the overactivation of T cells.
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Affiliation(s)
- Bo-Ra Na
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
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von Essen MR, Kongsbak M, Levring TB, Hansen AK, Boding L, Lauritsen JPH, Woetmann A, Baier G, Ødum N, Bonefeld CM, Geisler C. PKC-θ exists in an oxidized inactive form in naive human T cells. Eur J Immunol 2013; 43:1659-66. [DOI: 10.1002/eji.201243140] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 02/01/2013] [Accepted: 02/18/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Marina Rode von Essen
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Martin Kongsbak
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Trine Bøegh Levring
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Ann Kathrine Hansen
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Lasse Boding
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Jens Peter Holst Lauritsen
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Anders Woetmann
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Gottfried Baier
- Department of Medical Genetics; Molecular and Clinical Pharmacology; Innsbruck Medical University; Innsbruck; Austria
| | - Niels Ødum
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Charlotte Menné Bonefeld
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
| | - Carsten Geisler
- Department of International Health; Immunology and Microbiology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
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Casado P, Rodriguez-Prados JC, Cosulich SC, Guichard S, Vanhaesebroeck B, Joel S, Cutillas PR. Kinase-substrate enrichment analysis provides insights into the heterogeneity of signaling pathway activation in leukemia cells. Sci Signal 2013; 6:rs6. [PMID: 23532336 DOI: 10.1126/scisignal.2003573] [Citation(s) in RCA: 243] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Kinases determine the phenotypes of many cancer cells, but the frequency with which individual kinases are activated in primary tumors remains largely unknown. We used a computational approach, termed kinase-substrate enrichment analysis (KSEA), to systematically infer the activation of given kinase pathways from mass spectrometry-based phosphoproteomic analysis of acute myeloid leukemia (AML) cells. Experiments conducted in cell lines validated the approach and, furthermore, revealed that DNA-dependent protein kinase (DNA-PK) was activated as a result of inhibiting the phosphoinositide 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) signaling pathway. Application of KSEA to primary AML cells identified PI3K, casein kinases (CKs), cyclin-dependent kinases (CDKs), and p21-activated kinases (PAKs) as the kinase substrate groups most frequently enriched in this cancer type. Substrates phosphorylated by extracellular signal-regulated kinase (ERK) and cell division cycle 7 (CDC7) were enriched in primary AML cells that were resistant to inhibition of PI3K-mTOR signaling, whereas substrates of the kinases Abl, Lck, Src, and CDK1 were increased in abundance in inhibitor-sensitive cells. Modeling based on the abundances of these substrate groups accurately predicted sensitivity to a dual PI3K and mTOR inhibitor in two independent sets of primary AML cells isolated from patients. Thus, our study demonstrates KSEA as an untargeted method for the systematic profiling of kinase pathway activities and for increasing our understanding of diseases caused by the dysregulation of signaling pathways.
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Affiliation(s)
- Pedro Casado
- Analytical Signalling Group, Centre for Cell Signalling, Barts Cancer Institute, Queen Mary University of London, London EC1B 6BQ, UK.
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López-Huertas MR, Mateos E, Sánchez Del Cojo M, Gómez-Esquer F, Díaz-Gil G, Rodríguez-Mora S, López JA, Calvo E, López-Campos G, Alcamí J, Coiras M. The presence of HIV-1 Tat protein second exon delays fas protein-mediated apoptosis in CD4+ T lymphocytes: a potential mechanism for persistent viral production. J Biol Chem 2013; 288:7626-7644. [PMID: 23364796 DOI: 10.1074/jbc.m112.408294] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HIV-1 replication is efficiently controlled by the regulator protein Tat (101 amino acids) and codified by two exons, although the first exon (1-72 amino acids) is sufficient for this process. Tat can be released to the extracellular medium, acting as a soluble pro-apoptotic factor in neighboring cells. However, HIV-1-infected CD4(+) T lymphocytes show a higher resistance to apoptosis. We observed that the intracellular expression of Tat delayed FasL-mediated apoptosis in both peripheral blood lymphocytes and Jurkat cells, as it is an essential pathway to control T cell homeostasis during immune activation. Jurkat-Tat cells showed impairment in the activation of caspase-8, deficient release of mitochondrial cytochrome c, and delayed activation of both caspase-9 and -3. This protection was due to a profound deregulation of proteins that stabilized the mitochondrial membrane integrity, such as heat shock proteins, prohibitin, or nucleophosmin, as well as to the up-regulation of NF-κB-dependent anti-apoptotic proteins, such as BCL2, c-FLIPS, XIAP, and C-IAP2. These effects were observed in Jurkat expressing full-length Tat (Jurkat-Tat101) but not in Jurkat expressing the first exon of Tat (Jurkat-Tat72), proving that the second exon, and particularly the NF-κB-related motif ESKKKVE, was necessary for Tat-mediated protection against FasL apoptosis. Accordingly, the protection exerted by Tat was independent of its function as a regulator of both viral transcription and elongation. Moreover, these data proved that HIV-1 could have developed strategies to delay FasL-mediated apoptosis in infected CD4(+) T lymphocytes through the expression of Tat, thus favoring the persistent replication of HIV-1 in infected T cells.
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Affiliation(s)
- María Rosa López-Huertas
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - Elena Mateos
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - María Sánchez Del Cojo
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - Francisco Gómez-Esquer
- Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, 28922 Alcorcón, Madrid, Spain
| | - Gema Díaz-Gil
- Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, 28922 Alcorcón, Madrid, Spain
| | - Sara Rodríguez-Mora
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - Juan Antonio López
- Unidad de Proteómica, Centro Nacional de Investigaciones Cardiovasculares, 28029 Madrid, Spain
| | - Enrique Calvo
- Unidad de Proteómica, Centro Nacional de Investigaciones Cardiovasculares, 28029 Madrid, Spain
| | - Guillermo López-Campos
- Health and Biomedical Informatics Research Unit, Melbourne Medical School, 3010 Melbourne, Australia
| | - José Alcamí
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - Mayte Coiras
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain.
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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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Pfeifhofer-Obermair C, Thuille N, Baier G. Involvement of distinct PKC gene products in T cell functions. Front Immunol 2012; 3:220. [PMID: 22888329 PMCID: PMC3412260 DOI: 10.3389/fimmu.2012.00220] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 07/08/2012] [Indexed: 01/07/2023] Open
Abstract
It is well established that members of the protein kinase C (PKC) family seem to have important roles in T cells. Focusing on the physiological and non-redundant PKC functions established in primary mouse T cells via germline gene-targeting approaches, our current knowledge defines two particularly critical PKC gene products, PKCθ and PKCα, as the "flavor of PKC" in T cells that appear to have a positive role in signaling pathways that are necessary for full antigen receptor-mediated T cell activation ex vivo and T cell-mediated immunity in vivo. Consistently, in spite of the current dogma that PKCθ inhibition might be sufficient to achieve complete immunosuppressive effects, more recent results have indicated that the pharmacological inhibition of PKCθ, and additionally, at least PKCα, appears to be needed to provide a successful approach for the prevention of allograft rejection and treatment of autoimmune diseases.
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Affiliation(s)
| | | | - Gottfried Baier
- Division of Cell Genetics, Department of Pharmacology and Genetics, Medical University Innsbruck, Innsbruck,Tyrol, Austria
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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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46
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Astarci E, Sade A, Çimen I, Savaş B, Banerjee S. The NF-κB target genes ICAM-1 and VCAM-1 are differentially regulated during spontaneous differentiation of Caco-2 cells. FEBS J 2012; 279:2966-86. [DOI: 10.1111/j.1742-4658.2012.08677.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Wang X, Chuang HC, Li JP, Tan TH. Regulation of PKC-θ function by phosphorylation in T cell receptor signaling. Front Immunol 2012; 3:197. [PMID: 22798961 PMCID: PMC3393885 DOI: 10.3389/fimmu.2012.00197] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 06/11/2012] [Indexed: 01/03/2023] Open
Abstract
Protein kinase C (PKC)-θ is a serine/threonine kinase belonging to the calcium-independent novel PKC subfamily; its expression is restricted to certain tissues and cell types, including T cells. The signals delivered from T cell receptor (TCR) and CD28 costimulatory molecules trigger PKC-θ catalytic activation and membrane translocation to the immunological synapse, leading to activation of NF-κB, AP-1, and NF-AT. These transcription factors are important for T cell survival, activation, and differentiation. Phosphorylation of PKC-θ at multiple Ser/Thr/Tyr residues is induced in T cells during TCR signaling. Some phosphorylation sites play critical roles in the regulation of PKC-θ function and downstream signaling. The regulation mechanisms for PKC-θ phosphorylation sites are now being revealed. In this review, we discuss the current understanding of the regulation of PKC-θ function by phosphorylation during TCR signaling.
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Affiliation(s)
- Xiaohong Wang
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
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Kwon MJ, Ma J, Ding Y, Wang R, Sun Z. Protein kinase C-θ promotes Th17 differentiation via upregulation of Stat3. THE JOURNAL OF IMMUNOLOGY 2012; 188:5887-97. [PMID: 22586032 DOI: 10.4049/jimmunol.1102941] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although protein kinase C-θ (PKC-θ)-deficient mice are resistant to the induction of Th17-dependent experimental autoimmune encephalomyelitis, the function of PKC-θ in Th17 differentiation remains unknown. In this article, we show that purified, naive CD4 PKC-θ(-/-) T cells were defective in Th17 differentiation, whereas Th1 and Th2 differentiation appeared normal. Activation of PKC-θ with PMA promoted Th17 differentiation in wild type (WT) but not PKC-θ(-/-) T cells. Furthermore, PKC-θ(-/-) T cells had notably lower levels of Stat3, a transcription factor required for Th17 differentiation, and PMA markedly stimulated the expression of Stat3 in WT but not PKC-θ(-/-) T cells. In contrast, activation of Stat4 and Stat6, which are critical for Th1 and Th2 differentiation, was normal in PKC-θ(-/-) T cells. Forced expression of Stat3 significantly increased Th17 differentiation in PKC-θ(-/-) T cells, suggesting that reduced Stat3 levels were responsible for impaired Th17 differentiation, and that Stat3 lies downstream of PKC-θ. Constitutively active PKC-θ, or WT PKC-θ activated by either PMA or TCR cross-linking, stimulated expression of a luciferase reporter gene driven by the Stat3 promoter. PKC-θ-mediated activation of the Stat3 promoter was inhibited by dominant-negative AP-1 and IκB kinase-β, but stimulated by WT AP-1 and IκB kinase-β, suggesting that PKC-θ stimulates Stat3 transcription via the AP-1 and NF-κB pathways. Lastly, conditions favoring Th17 differentiation induced the highest activation level of PKC-θ. Altogether, the data indicate that PKC-θ integrates the signals from TCR signaling and Th17 priming cytokines to upregulate Stat3 via NF-κB and AP-1, resulting in the stimulation of Th17 differentiation.
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Affiliation(s)
- Myung-Ja Kwon
- Division of Immunology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
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Schmidt A, Oberle N, Krammer PH. Molecular mechanisms of treg-mediated T cell suppression. Front Immunol 2012; 3:51. [PMID: 22566933 PMCID: PMC3341960 DOI: 10.3389/fimmu.2012.00051] [Citation(s) in RCA: 462] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 03/01/2012] [Indexed: 12/22/2022] Open
Abstract
CD4(+)CD25(high)Foxp3(+) regulatory T cells (Tregs) can suppress other immune cells and, thus, are critical mediators of peripheral self-tolerance. On the one hand, Tregs avert autoimmune disease and allergies. On the other hand, Tregs can prevent immune reactions against tumors and pathogens. Despite the importance of Tregs, the molecular mechanisms of suppression remain incompletely understood and controversial. Proliferation and cytokine production of CD4(+)CD25(-) conventional T cells (Tcons) can be inhibited directly by Tregs. In addition, Tregs can indirectly suppress Tcon activation via inhibition of the stimulatory capacity of antigen presenting cells. Direct suppression of Tcons by Tregs can involve immunosuppressive soluble factors or cell contact. Different mechanisms of suppression have been described, so far with no consensus on one universal mechanism. Controversies might be explained by the fact that different mechanisms may operate depending on the site of the immune reaction, on the type and activation state of the suppressed target cell as well as on the Treg activation status. Further, inhibition of T cell effector function can occur independently of suppression of proliferation. In this review, we summarize the described molecular mechanisms of suppression with a particular focus on suppression of Tcons and rapid suppression of T cell receptor-induced calcium (Ca(2+)), NFAT, and NF-κB signaling in Tcons by Tregs.
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Affiliation(s)
- Angelika Schmidt
- Division of Immunogenetics, Tumorimmunology Program, German Cancer Research Center (DKFZ) Heidelberg, Germany
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Lee JY, Choi AY, Oh YT, Choe W, Yeo EJ, Ha J, Kang I. AMP-activated protein kinase mediates T cell activation-induced expression of FasL and COX-2 via protein kinase C theta-dependent pathway in human Jurkat T leukemia cells. Cell Signal 2012; 24:1195-207. [PMID: 22330070 DOI: 10.1016/j.cellsig.2012.01.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 01/27/2012] [Accepted: 01/27/2012] [Indexed: 12/17/2022]
Abstract
AMP-activated protein kinase (AMPK), an important regulator of energy homeostasis, is known to be activated during T cell activation. T cell activation by T cell receptor (TCR) engagement or its pharmacological mimics, PMA plus ionomycin (PMA/Io), induces immunomodulatory FasL and cyclooxygenase-2 (COX-2) expression. In this study, we examined the role and mechanisms of AMPK in PMA/Io-induced expression of FasL and COX-2 in Jurkat T human leukemic cells. Inhibition of AMPK by a pharmacological agent, compound C, or AMPKα1 siRNA suppressed expression of FasL and COX-2 mRNAs and proteins in PMA/Io-activated Jurkat cells. It also reduced secretion of FasL protein and prostaglandin E2, a main product of COX-2, in Jurkat cells and peripheral blood lymphocytes activated with PMA/Io or monoclonal anti-CD3 plus anti-CD28. Consistently, inhibition of AMPK blocked promoter activities of FasL and COX-2 in activated Jurkat cells. As protein kinase C theta (PKCθ) is a central molecule for TCR signaling, we examined any possible cross-talk between AMPK and PKCθ in activated T cells. Of particular importance, we found that inhibition of AMPK blocked phosphorylation and activation of PKCθ, suggesting that AMPK is an upstream kinase of PKCθ. Moreover, we showed that AMPK was directly associated with PKCθ and phosphorylated Thr538 of PKCθ in PMA/Io-stimulated Jurkat cells. We also showed that inhibition of PKCθ by rottlerin or dominant negative PKCθ reduced AMPK-mediated transcriptional activation of NF-AT and AP-1 in activated Jurkat cells. Taken together, these results suggest that AMPK regulates expression of FasL and COX-2 via the PKCθ and NF-AT and AP-1 pathways in activated Jurkat cells.
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Affiliation(s)
- Jung Yeon Lee
- Department of Biochemistry and Molecular Biology, School of Medicine, Medical Research Center for Bioreaction to Reactive Oxygen Species, Biomedical Science Institute, Kyung Hee University, Seoul 130-701, Republic of Korea
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