51
|
Gomez-Cambronero J, Di Fulvio M, Knapek K. Understanding phospholipase D (PLD) using leukocytes: PLD involvement in cell adhesion and chemotaxis. J Leukoc Biol 2007; 82:272-81. [PMID: 17431093 DOI: 10.1189/jlb.0107033] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Phospholipase D (PLD) is an enzyme that catalyzes the conversion of membrane phosphatidylcholine to choline and phosphatidic acid (PA; a second messenger). PLD is expressed in nearly all types of leukocytes and has been associated with phagocytosis, degranulation, microbial killing, and leukocyte maturation. With the application of recently developed molecular tools (i.e., expression vectors, silencing RNA, and specific antibodies), the demonstration of a key role for PLD in those and related cellular actions has contributed to a better awareness of its importance. A case in point is the recent findings that RNA interference-mediated depletion of PLD results in impaired leukocyte adhesion and chemotaxis toward a gradient of chemokines, implying that PLD is necessary for leukocyte movement. We forecast that based on results such as those, leukocytes may prove to be useful tools to unravel still-unresolved mechanistic issues in the complex biology of PLD. Three such issues are considered here: first, whether the cellular actions of PLD are mediated entirely by PA (the product of its enzymatic reaction) or whether PLD by itself interacts with other protein signaling molecules; second, the current difficulty of defining a "PA consensus site" in the various intracellular protein targets of PA; and third, the resolution of specific PLD location (upstream or downstream) in a particular effector signaling cascade. There are reasons to expect that leukocytes and their leukemic cell line counterparts will continue yielding invaluable information to cell biologists to resolve standing molecular and functional issues concerning PLD.
Collapse
Affiliation(s)
- Julian Gomez-Cambronero
- Wright State University School of Medicine, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA.
| | | | | |
Collapse
|
52
|
Abstract
Protein kinase Cs (PKCs) are implicated in many forms of synaptic plasticity. However, the specific isoform(s) of PKC that underlie(s) these events are often not known. We have used Aplysia as a model system in order to investigate the isoform specificity of PKC actions due to the presence of fewer isoforms and a large number of documented physiological roles for PKC in synaptic plasticity in this system. In particular, we have shown that distinct isoforms mediate distinct types of synaptic plasticity induced by the same neurotransmitter: The novel calcium-independent PKC Apl II is required for actions mediated by serotonin (5-HT) alone, while the classical calcium-dependent PKC Apl I is required for actions mediated when 5-HT is coupled to activity. We will discuss the reasons for PKC isoform specificity, assess the tools used to uncover isoform specificity, and discuss the implications of isoform specificity for understanding the roles of PKC in regulating synaptic plasticity.
Collapse
Affiliation(s)
- Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
| |
Collapse
|
53
|
Lee JG, Lee SH, Park DW, Bae YS, Yun SS, Kim JR, Baek SH. Phosphatidic acid as a regulator of matrix metalloproteinase-9 expression via the TNF-α signaling pathway. FEBS Lett 2007; 581:787-93. [PMID: 17276429 DOI: 10.1016/j.febslet.2007.01.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 01/22/2007] [Indexed: 12/24/2022]
Abstract
Phosphatidic acid (PA) is implicated in pathophysiological processes associated with cellular signaling events and inflammation, which include the expressional regulation of numerous genes. Here, we show that PA stimulation increases matrix metalloproteinase-9 (MMP-9) expression in macrophages through tumor necrosis factor (TNF)-alpha signaling. We performed antibody array analysis on proteins from macrophages stimulated with PA. PA was found to induce the production of TNF-alpha, but not of TNF receptor (TNFR)1 and TNFR2 in a time-dependent manner and stimulated significant, though delayed, MMP-9 expression. PA induced the phosphorylations of both ERK1/2 and p38, but not of c-jun amino-terminal kinase. Moreover, only ERK1/2 inhibition by U0126 suppressed PA-induced TNF-alpha production and MMP-9 expression. Neutralizing TNF-alpha, TNFR1 or TNFR2 antibodies significantly suppressed PA-induced MMP-9 expression, suggesting that the production of TNF-alpha in response to PA preceded the expression of MMP-9. Moreover, lipopolysaccharide-induced PA also led to TNF-alpha release and resulted in MMP-9 expression. Taken together, these observations suggest that PA may play a role in MMP-9 regulation through ERKs/TNF-alpha/TNFRs-dependent signaling pathway.
Collapse
Affiliation(s)
- Jin-Gu Lee
- Department of Biochemistry & Molecular Biology, Aging-Associated Vascular Disease Research Center, Yeungnam University, Daegu 705-717, Republic of Korea
| | | | | | | | | | | | | |
Collapse
|
54
|
Mane SP, Vasquez-Robinet C, Sioson AA, Heath LS, Grene R. Early PLDalpha-mediated events in response to progressive drought stress in Arabidopsis: a transcriptome analysis. JOURNAL OF EXPERIMENTAL BOTANY 2007; 58:241-52. [PMID: 17261695 DOI: 10.1093/jxb/erl262] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Phospholipase D (PLD) has been implicated in a variety of stresses including osmotic stress and wounding. PLDalpha1-derived phosphatidic acid interacts with ABI1 phosphatase 2C and promotes abscisic acid signalling. It has also been shown to regulate proline biosynthesis negatively. Plants with abrogated PLDalpha show insensitivity to abscisic acid (ABA) and impaired stomatal conductance. The goal in the present study was to identify early PLDalpha-mediated events in response to progressive drought stress in Arabidopsis. Water was withheld from 7-week-old Arabidopsis thaliana (Col-0) and antisense-PLDalpha1 (anti-PLDalpha) in a controlled environment chamber. Diurnal leaf water potential (LWP) and photosynthesis measurements were recorded five and three times a day, respectively. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and microarray analyses were conducted using RNA from shoots collected at the fourth LWP time point on the ninth day after stress imposition. Anti-PLDalpha experienced severe water stress (-1.28 MPa) at the same time period that Col-0 experienced less water stress (-0.31 MPa). Diurnal LWP measurements showed that anti-PLDalpha had a lower LWP than Col-0 in both control and drought-stress conditions. Photosynthesis was also more affected in anti-PLDalpha than in Col-0. Anti-PLDalpha plants recovered fully following rehydration after 10 d of stress. qRT-PCR revealed up to 18-fold lower values for PLDalpha transcripts in stressed anti-PLDalpha plants when compared with stressed Col-0. Microarray expression profiles revealed distinct gene expression patterns in Col-0 and anti-PLDalpha. No differences in gene expression were detected between the two genotypes in the absence of drought stress. ROP8, PLDdelta, and lipid transfer proteins were among the differentially expressed genes between the two genotypes.
Collapse
Affiliation(s)
- Shrinivasrao P Mane
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061, USA
| | | | | | | | | |
Collapse
|
55
|
Kim MJ, Choi MU, Kim CW. Activation of phospholipase D1 by surface roughness of titanium in MG63 osteoblast-like cell. Biomaterials 2006; 27:5502-11. [PMID: 16857255 DOI: 10.1016/j.biomaterials.2006.06.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 06/29/2006] [Indexed: 01/31/2023]
Abstract
Although it is recognized that the surface roughness of titanium (Ti) promotes the osteogenic differentiation, the related mechanisms and factors remain elusive. The purpose of this study was to explore the potential correlation among phospholipase D (PLD) activity, Ti surface roughness and subsequent osteoblast differentiation. The machined Ti disks were sandblasted with aluminum oxide particles to produce surfaces of varying roughness (n = 160). Normal or transfected MG63cells with PLD genes were cultured on roughened Ti specimens and assayed for PLD, alkaline phosphatase (ALP) and osteocalcin. The statistical significance was evaluated by analysis of variance. The activity, mRNA and protein levels of PLD significantly increased in MG63 cells with a roughness-dependent pattern (P < 0.05). The ALP activity and osteocalcin production, promoted by Ti surface roughness, were enhanced by the PLD activator and inhibited by the PLD blocker. It was also found that the PLD1 isoform responds to Ti surface roughness and regulates selectively the ALP activity. These observations strongly suggest that PLD1 mediates the cellular signaling of and modulates osteoblast differentiation induced by Ti surface roughness in MG63 osteoblast-like cell.
Collapse
Affiliation(s)
- Myung-Joo Kim
- Department of Prosthodontics and Dental Research Institute, Colleage of Dentistry, Seoul National University, Chongro-gu, Seoul 110-749, South Korea
| | | | | |
Collapse
|
56
|
Corbalán-García S, Gómez-Fernández JC. Protein kinase C regulatory domains: the art of decoding many different signals in membranes. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:633-54. [PMID: 16809062 DOI: 10.1016/j.bbalip.2006.04.015] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 04/27/2006] [Accepted: 04/28/2006] [Indexed: 11/29/2022]
Abstract
Protein kinase C (PKC) is a member of a family of Ser/Thr phosphotransferases that are involved in many cellular signaling pathways. These enzymes possess two regulatory domains, C1 and C2, that are the targets of different second messengers. The purpose of this review is to describe in molecular terms the diverse mechanisms of activation of PKCs in the light of very significant advances made in this field over recent years. The role of some critical amino acid residues concerning activation of the enzymes and their location within known structures of isolated domains will be presented. For example, the recently deduced 3D structures of the C2 domains show that these domains can additionally act as PtdIns(4,5)P(2)-binding or phosphotyrosine-binding modules depending on the isoenzyme. All these capacities to play different roles in the cell wide web of signals underline the notion that we are dealing with a multifunctional family of enzymes which, after 30 years of investigation, we are just beginning to understand.
Collapse
Affiliation(s)
- Senena Corbalán-García
- Dpto. de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad de Murcia, Apdo. 4021, E-30100 Murcia, Spain.
| | | |
Collapse
|
57
|
Hucho TB, Dina OA, Levine JD. Epac mediates a cAMP-to-PKC signaling in inflammatory pain: an isolectin B4(+) neuron-specific mechanism. J Neurosci 2006; 25:6119-26. [PMID: 15987941 PMCID: PMC6725047 DOI: 10.1523/jneurosci.0285-05.2005] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The epsilon isoform of protein kinase C (PKCepsilon) has emerged as a critical second messenger in sensitization toward mechanical stimulation in models of neuropathic (diabetes, alcoholism, and cancer therapy) as well as acute and chronic inflammatory pain. Signaling pathways leading to activation of PKCepsilon remain unknown. Recent results indicate signaling from cAMP to PKC. A mechanism connecting cAMP and PKC, two ubiquitous, commonly considered separate pathways, remains elusive. We found that, in cultured DRG neurons, signaling from cAMP to PKCepsilon is not mediated by PKA but by the recently identified cAMP-activated guanine exchange factor Epac. Epac, in turn, was upstream of phospholipase C (PLC) and PLD, both of which were necessary for translocation and activation of PKCepsilon. This signaling pathway was specific to isolectin B4-positive [IB4(+)] nociceptors. Also, in a behavioral model, cAMP produced mechanical hyperalgesia (tenderness) through Epac, PLC/PLD, and PKCepsilon. By delineating this signaling pathway, we provide a mechanism for cAMP-to-PKC signaling, give proof of principle that the mitogen-activated protein kinase pathway-activating protein Epac also stimulates PKC, describe the first physiological function unique for the IB4(+) subpopulation of sensory neurons, and find proof of principle that G-protein-coupled receptors can activate PKC not only through the G-proteins alpha(q) and betagamma but also through alpha(s).
Collapse
Affiliation(s)
- Tim B Hucho
- National Institutes of Health Pain Center, University of California, San Francisco, San Francisco, California 94143, USA.
| | | | | |
Collapse
|
58
|
Cheeseman KL, Ueyama T, Michaud TM, Kashiwagi K, Wang D, Flax LA, Shirai Y, Loegering DJ, Saito N, Lennartz MR. Targeting of protein kinase C-epsilon during Fcgamma receptor-dependent phagocytosis requires the epsilonC1B domain and phospholipase C-gamma1. Mol Biol Cell 2005; 17:799-813. [PMID: 16319178 PMCID: PMC1356590 DOI: 10.1091/mbc.e04-12-1100] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Protein kinase C-epsilon (PKC-epsilon) translocates to phagosomes and promotes uptake of IgG-opsonized targets. To identify the regions responsible for this concentration, green fluorescent protein (GFP)-protein kinase C-epsilon mutants were tracked during phagocytosis and in response to exogenous lipids. Deletion of the diacylglycerol (DAG)-binding epsilonC1 and epsilonC1B domains, or the epsilonC1B point mutant epsilonC259G, decreased accumulation at phagosomes and membrane translocation in response to exogenous DAG. Quantitation of GFP revealed that epsilonC259G, epsilonC1, and epsilonC1B accumulation at phagosomes was significantly less than that of intact PKC-epsilon. Also, the DAG antagonist 1-hexadecyl-2-acetyl glycerol (EI-150) blocked PKC-epsilon translocation. Thus, DAG binding to epsilonC1B is necessary for PKC-epsilon translocation. The role of phospholipase D (PLD), phosphatidylinositol-specific phospholipase C (PI-PLC)-gamma1, and PI-PLC-gamma2 in PKC-epsilon accumulation was assessed. Although GFP-PLD2 localized to phagosomes and enhanced phagocytosis, PLD inhibition did not alter target ingestion or PKC-epsilon localization. In contrast, the PI-PLC inhibitor U73122 decreased both phagocytosis and PKC-epsilon accumulation. Although expression of PI-PLC-gamma2 is higher than that of PI-PLC-gamma1, PI-PLC-gamma1 but not PI-PLC-gamma2 consistently concentrated at phagosomes. Macrophages from PI-PLC-gamma2-/- mice were similar to wild-type macrophages in their rate and extent of phagocytosis, their accumulation of PKC-epsilon at the phagosome, and their sensitivity to U73122. This implicates PI-PLC-gamma1 as the enzyme that supports PKC-epsilon localization and phagocytosis. That PI-PLC-gamma1 was transiently tyrosine phosphorylated in nascent phagosomes is consistent with this conclusion. Together, these results support a model in which PI-PLC-gamma1 provides DAG that binds to epsilonC1B, facilitating PKC-epsilon localization to phagosomes for efficient IgG-mediated phagocytosis.
Collapse
Affiliation(s)
- Keylon L Cheeseman
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, NY 12208, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
59
|
Newton PM, Messing RO. Intracellular signaling pathways that regulate behavioral responses to ethanol. Pharmacol Ther 2005; 109:227-37. [PMID: 16102840 DOI: 10.1016/j.pharmthera.2005.07.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022]
Abstract
Recent evidence indicates that ethanol modulates the function of specific intracellular signaling cascades, including those that contain cyclic adenosine 3', 5'-monophosphate (cAMP)-dependent protein kinase A (PKA), protein kinase C (PKC), the tyrosine kinase Fyn, and phospholipase D (PLD). In some cases, the specific components of these cascades appear to mediate the effects of ethanol, whereas other components indirectly modify responses to ethanol. Studies utilizing selective inhibitors and genetically modified mice have identified specific isoforms of proteins involved in responses to ethanol. The effects of ethanol on neuronal signaling appear restricted to certain brain regions, partly due to the restricted distribution of these proteins. This likely contributes specificity to ethanol's actions on behavior. This review summarizes recent work on ethanol and intracellular signal transduction, emphasizing studies that have identified specific molecular events that underlie behavioral responses to ethanol.
Collapse
Affiliation(s)
- P M Newton
- The Ernest Gallo Clinic and Research Center, Department of Neurology, University of California at San Francisco, 5858 Horton Street, Suite 200, Emeryville, CA 94608, United States
| | | |
Collapse
|
60
|
Testerink C, Munnik T. Phosphatidic acid: a multifunctional stress signaling lipid in plants. TRENDS IN PLANT SCIENCE 2005; 10:368-75. [PMID: 16023886 DOI: 10.1016/j.tplants.2005.06.002] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 04/22/2005] [Accepted: 06/28/2005] [Indexed: 05/03/2023]
Abstract
Phosphatidic acid (PA) has only recently been identified as an important signaling molecule in both plants and animals. Nonetheless, it already promises to rival the importance of the classic second messengers Ca(2+) and cAMP. In plants, its formation is triggered in response to various biotic and abiotic stress factors, including pathogen infection, drought, salinity, wounding and cold. In general, PA signal production is fast (minutes) and transient. Recently, our understanding of the role of PA formation in stress responses as a result of phospholipases C and D activity has greatly increased. Moreover, the first protein targets of PA have been identified. Based on this recent work, potential mechanisms by which PA provokes downstream effects are emerging.
Collapse
Affiliation(s)
- Christa Testerink
- Section of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, The Netherlands
| | | |
Collapse
|
61
|
Abstract
The Z-line represents a critical link between the transverse tubule network and cytoskeleton of cardiac cells with a role in anchoring structural proteins, ion channels, and signaling molecules. Protein kinase C-epsilon (PKC-epsilon) regulates cardiac excitability, cardioprotection, and growth, possibly as a consequence of translocation to the Z-line/T tubule region. To investigate the mechanism of PKC-epsilon translocation, fragments of its NH2-terminal 144-amino acid variable domain, epsilonV1, were fused with green fluorescent protein and evaluated by quantitative Fourier image analysis of decorated myocytes. Deletion of 23 amino acids from the NH2-terminus of epsilonV1, including an EAVSLKPT motif important for binding to a receptor for activated C kinase (RACK2), reduced but did not abolish Z-line binding. Further deletions of up to 84 amino acids from the NH2-terminus of epsilonV1 also did not prevent Z-line decoration. However, deletions of residues 85-144 from the COOH-terminus strongly reduced Z-line binding. COOH-terminal deletions caused 2.5-fold greater loss of binding energy (deltadeltaG) than did NH2-terminal deletions. Synthetic peptides derived from these regions modulated epsilonV1 binding and cardiac myocyte function, but also revealed considerable heterogeneity within populations of adult cardiac myocytes. The COOH-terminal subdomain important for Z-line anchoring maps to a surface in the epsilonV1 crystal structure that complements the eight-amino acid RACK2 binding site and two previously identified membrane docking motifs. PKC-epsilon anchoring at the cardiac Z-line/T tubule appears to rely on multiple points of contact probably involving protein-lipid and protein-protein interactions.
Collapse
Affiliation(s)
- Seth L Robia
- Dept. of Physiology, University of Wisconsin, Madison, WI 53706, USA
| | | | | |
Collapse
|
62
|
Stahelin RV, Digman MA, Medkova M, Ananthanarayanan B, Melowic HR, Rafter JD, Cho W. Diacylglycerol-induced Membrane Targeting and Activation of Protein Kinase Cϵ. J Biol Chem 2005; 280:19784-93. [PMID: 15769752 DOI: 10.1074/jbc.m411285200] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Two novel protein kinases C (PKC), PKCdelta and PKCepsilon, have been reported to have opposing functions in some mammalian cells. To understand the basis of their distinct cellular functions and regulation, we investigated the mechanism of in vitro and cellular sn-1,2-diacylglycerol (DAG)-mediated membrane binding of PKCepsilon and compared it with that of PKCdelta. The regulatory domains of novel PKC contain a C2 domain and a tandem repeat of C1 domains (C1A and C1B), which have been identified as the interaction site for DAG and phorbol ester. Isothermal titration calorimetry and surface plasmon resonance measurements showed that isolated C1A and C1B domains of PKCepsilon have comparably high affinities for DAG and phorbol ester. Furthermore, in vitro activity and membrane binding analyses of PKCepsilon mutants showed that both the C1A and C1B domains play a role in the DAG-induced membrane binding and activation of PKCepsilon. The C1 domains of PKCepsilon are not conformationally restricted and readily accessible for DAG binding unlike those of PKCdelta. Consequently, phosphatidylserine-dependent unleashing of C1 domains seen with PKCdelta was not necessary for PKCepsilon. Cell studies with fluorescent protein-tagged PKCs showed that, due to the lack of lipid headgroup selectivity, PKCepsilon translocated to both the plasma membrane and the nuclear membrane, whereas PKCdelta migrates specifically to the plasma membrane under the conditions in which DAG is evenly distributed among intracellular membranes of HEK293 cells. Also, PKCepsilon translocated much faster than PKCdelta due to conformational flexibility of its C1 domains. Collectively, these results provide new insight into the differential activation mechanisms of PKCdelta and PKCepsilon based on different structural and functional properties of their C1 domains.
Collapse
Affiliation(s)
- Robert V Stahelin
- Department of Chemistry, University of Illinois, Chicago, 60607, USA
| | | | | | | | | | | | | |
Collapse
|
63
|
Gómez-Fernández JC, Torrecillas A, Corbalán-García S. Diacylglycerols as activators of protein kinase C. Mol Membr Biol 2005; 21:339-49. [PMID: 15764364 DOI: 10.1080/09687860400010508] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Diacylglycerols are generated in the membrane as the result of extracellular signals and are able to stimulate the activity of protein kinase C, acting as membrane second messengers. Diacylglycerols are recognized by protein kinases C through the C1 domain and established models propose that they will stabilize the translocation of the protein to the membrane. However, diacylglycerols also act by modulating the physical properties of the membrane, thus favouring the translocation of the enzyme. This is done through alteration of the membrane surface curvature, dehydration of the surface and the separation of phospholipid surface groups. Good correlations have been observed between the physical state of the membrane and protein kinase C activity.
Collapse
Affiliation(s)
- Juan C Gómez-Fernández
- Departamento de Bioquimica y Biologia Molecular (A) Facultad de Veterinaria, Universidad de Murcia, Apartado de Correos 4021, E-30080-Murcia, Spain.
| | | | | |
Collapse
|
64
|
Furumoto Y, Gonzalez-Espinosa C, Gomez G, Kovarova M, Odom S, Parravicini V, Ryana JJ, Rivera J. Rethinking the role of Src family protein tyrosine kinases in the allergic response: new insights on the functional coupling of the high affinity IgE receptor. Immunol Res 2005; 30:241-53. [PMID: 15477664 DOI: 10.1385/ir:30:2:241] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Antigen-induced cross-linking of immunoglobulin E (IgE) antibodies bound to the high-affinity IgE receptor (FcepsilonRI), on mast cells results in the release of mediators that initiate an inflammatory response. This normal immune response has been abducted by immunological adaptation, through the production of IgE antibodies to normally innocuous substances, to cause allergic disease. Therefore, understanding the molecular requirements in IgE-dependent mast-cell activation holds promise for therapeutic intervention in disease. Recent investigation on the functional coupling of FcepsilonRI to the intracellular signaling apparatus has provided paradigm-altering insights on the importance and function of Src family protein tyrosine kinases (Src PTK) in mast-cell activation. In this synopsis, we review the current knowledge on the role of the Src PTKs, Fyn and Lyn, in mast-cell activation and discuss the implications of our findings on allergic disease.
Collapse
Affiliation(s)
- Yasuko Furumoto
- Molecular Inflammation Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | | | | | | | |
Collapse
|
65
|
Loers G, Chen S, Grumet M, Schachner M. Signal transduction pathways implicated in neural recognition molecule L1 triggered neuroprotection and neuritogenesis. J Neurochem 2005; 92:1463-76. [PMID: 15748164 DOI: 10.1111/j.1471-4159.2004.02983.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The signal transduction pathways involved in adhesion molecule L1-triggered neuritogenesis and neuroprotection were investigated using the extracellular domain of mouse or human L1 in fusion with the Fc portion of human immunoglobulin G or L1 purified from mouse brain by affinity chromatography. Substrate L1-triggered neuritogenesis and neuroprotection depended on distinct but also overlapping signal transduction pathways and on the expression of L1 at the neuronal cell surface. PI3 kinase inhibitors, Src family kinase inhibitors as well as mitogen-activated protein kinase kinase inhibitors reduced both L1-triggered neuritogenesis and neuroprotection. In contrast, fibroblast growth factor receptor inhibitors, a protein kinase A inhibitor, and an inhibitor of cAMP-mediated signal transduction pathways, blocked neuritogenesis, but did not affect L1-triggered neuroprotection. Proteolytic cleavage of L1 or its interaction partners is necessary for both L1-mediated neuritogensis and neuroprotection. Furthermore, L1-triggered neuroprotection was found to be associated with increased phosphorylation of extracellular signal-regulated kinases 1/2, Akt and Bad, and inhibition of caspases. These observations suggest possibilities of differentially targeting signal transduction pathways for L1-dependent neuritogenesis and neuroprotection.
Collapse
Affiliation(s)
- Gabriele Loers
- Zentrum für Molekulare Neurobiologie Hamburg, Universität Hamburg, Falkenried 94, D-20251 Hamburg, Germany
| | | | | | | |
Collapse
|
66
|
Conesa-Zamora P, Mollinedo F, Corbalán-García S, Gómez-Fernández JC. A comparative study of the effect of the antineoplastic ether lipid 1-O-octadecyl-2-O-methyl-glycero-3-phosphocholine and some homologous compounds on PKCα and PKCɛ. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1687:110-9. [PMID: 15708359 DOI: 10.1016/j.bbalip.2004.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 11/11/2004] [Accepted: 11/11/2004] [Indexed: 11/25/2022]
Abstract
The effects of the anti-neoplastic ether lipid ET-18-OCH3 and some structural homologues on the activity of protein kinase C alpha (PKC alpha) were studied and compared with the effects the same had on the activity of PKC epsilon. ET-18-OCH3 progressively inhibited the activity of PKC alpha as the concentration was increased up to 30 mol% of the total lipid, above which the effect was one of activation. The experiments carried out with the homologues showed that the methoxy group bound at the sn-2 position of the glycerol of ET-18-OCH3 is essential for both the initial inhibitory effect and the subsequent activation effect. On the other hand, variations in the type of bond linking substitutions in the sn-1 position, ether or ester, do not seem to play an important role in determining the activity of the enzyme. The effects were different on PKC epsilon since ET-18-OCH3 had a triphasic effect, activating the enzyme at low concentrations, inhibiting it at slightly higher concentrations and then activating it again at higher concentrations. In this case, when the homologues were used, it was observed that the presence of the methoxy group linked to the sn-2 position of glycerol and the type of bond linking substitutions to the sn-1 position were important for activating the enzyme, so that only homologues with ester bonds as LPC and PAPC were able to induce the initial activation step in a way similar to ET-18-OCH3. Substitution of the phosphocholine group of ET-18-OCH3 by phosphoserine led to a greater activation of PKC alpha, an effect that comes from the Ca(2+)-phospholipid binding site probably because of the specific interaction of this site with the phosphoserine group. The action of ET-18-OCH3 and its homologues, as demonstrated in this paper, may permit the selective inhibition or activation of PKC alpha and PKC epsilon by using the most suitable range of concentrations.
Collapse
Affiliation(s)
- Pablo Conesa-Zamora
- Departamento de Bioquímica y Biología Molecular A, Facultad de Veterinaria, Universidad de Murcia, Apartado de Correos 4021, E-30080-Murcia, Spain
| | | | | | | |
Collapse
|
67
|
Avila-Flores A, Santos T, Rincón E, Mérida I. Modulation of the mammalian target of rapamycin pathway by diacylglycerol kinase-produced phosphatidic acid. J Biol Chem 2005; 280:10091-9. [PMID: 15632115 DOI: 10.1074/jbc.m412296200] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protein known as mammalian target of rapamycin (mTOR) regulates cell growth by integrating different stimuli, such as available nutrients and mitogenic factors. The lipid messenger phosphatidic acid (PA) binds and positively regulates the mitogenic response of mTOR. PA generator enzymes are consequently potential regulators of mTOR. Here we explored the contribution to this pathway of the enzyme diacylglycerol kinase (DGK), which produces PA through phosphorylation of diacylglycerol. We found that overexpression of the DGKzeta, but not of the alpha isoform, in serum-deprived HEK293 cells induced mTOR-dependent phosphorylation of p70S6 kinase (p70S6K). After serum addition, p70S6K phosphorylation was higher and more resistant to rapamycin treatment in cells overexpressing DGKzeta. The effect of this DGK isoform on p70S6K hyperphosphorylation required the mTOR PA binding region. Down-regulation of endogenous DGKzeta by small interfering RNA in HEK293 cells diminished serum-induced p70S6K phosphorylation, highlighting the role of this isoform in the mTOR pathway. Our results confirm a role for PA in mTOR regulation and describe a novel pathway in which DGKzeta-derived PA acts as a mediator of mTOR signaling.
Collapse
Affiliation(s)
- Antonia Avila-Flores
- Department of Immunology and Oncology, National Centre for Biotechnology, Consejo Superior de Investigaciones Científicas, Campus Cantoblanco, E-28049 Madrid, Spain
| | | | | | | |
Collapse
|
68
|
Zambonelli C, Roberts MF. Non-HKD Phospholipase D Enzymes: New Players in Phosphatidic Acid Signaling? ACTA ACUST UNITED AC 2005; 79:133-81. [PMID: 16096028 DOI: 10.1016/s0079-6603(04)79003-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- Carlo Zambonelli
- Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | | |
Collapse
|
69
|
Komati H, Naro F, Mebarek S, De Arcangelis V, Adamo S, Lagarde M, Prigent AF, Némoz G. Phospholipase D is involved in myogenic differentiation through remodeling of actin cytoskeleton. Mol Biol Cell 2004; 16:1232-44. [PMID: 15616193 PMCID: PMC551488 DOI: 10.1091/mbc.e04-06-0459] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We investigated the role of phospholipase D (PLD) and its product phosphatidic acid (PA) in myogenic differentiation of cultured L6 rat skeletal myoblasts. Arginine-vasopressin (AVP), a differentiation inducer, rapidly activated PLD in a Rho-dependent way, as shown by almost total suppression of activation by C3 exotoxin pretreatment. Addition of 1-butanol, which selectively inhibits PA production by PLD, markedly decreased AVP-induced myogenesis. Conversely, myogenesis was potentiated by PLD1b isoform overexpression but not by PLD2 overexpression, establishing that PLD1 is involved in this process. The expression of the PLD isoforms was differentially regulated during differentiation. AVP stimulation of myoblasts induced the rapid formation of stress fiber-like actin structures (SFLSs). 1-Butanol selectively inhibited this response, whereas PLD1b overexpression induced SFLS formation, showing that it was PLD dependent. Endogenous PLD1 was located at the level of SFLSs, and by means of an intracellularly expressed fluorescent probe, PA was shown to be accumulated along these structures in response to AVP. In addition, AVP induced a PLD-dependent neosynthesis of phosphatidylinositol 4,5-bisphosphate (PIP2), which also was accumulated along actin fibers. These data support the hypothesis that PLD participates in myogenesis through PA- and PIP2-dependent actin fiber formation.
Collapse
Affiliation(s)
- Hiba Komati
- Laboratoire de Physiopathologie des Lipides et Membranes, Institut National de la Santé et de la Recherche Médicale Unité 585, Institut National des Sciences Appliquées de Lyon, 69621 Villeurbanne, France
| | | | | | | | | | | | | | | |
Collapse
|
70
|
Delon C, Manifava M, Wood E, Thompson D, Krugmann S, Pyne S, Ktistakis NT. Sphingosine kinase 1 is an intracellular effector of phosphatidic acid. J Biol Chem 2004; 279:44763-74. [PMID: 15310762 DOI: 10.1074/jbc.m405771200] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sphingosine kinase 1 (SK1) phosphorylates sphingosine to generate sphingosine 1-phosphate (S1P). Because both substrate and product of the enzyme are potentially important signaling molecules, the regulation of SK1 is of considerable interest. We report that SK1, which is ordinarily a cytosolic enzyme, translocates in vivo and in vitro to membrane compartments enriched in phosphatidic acid (PA), the lipid product of phospholipase D. This translocation depends on direct interaction of SK1 with PA, because recombinant purified enzyme shows strong affinity for pure PA coupled to Affi-Gel. The SK1-PA interaction maps to the C terminus of SK1 and is independent of catalytic activity or of the diacylglycerol kinase-like domain of the enzyme. Thus SK1 constitutes a novel, physiologically relevant PA effector.
Collapse
Affiliation(s)
- Christine Delon
- Department of Signalling, Babraham Institute, Cambridge CB2 4AT, United Kingdom
| | | | | | | | | | | | | |
Collapse
|