201
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Ebisuya M, Kondoh K, Nishida E. The duration, magnitude and compartmentalization of ERK MAP kinase activity: mechanisms for providing signaling specificity. J Cell Sci 2006; 118:2997-3002. [PMID: 16014377 DOI: 10.1242/jcs.02505] [Citation(s) in RCA: 263] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
ERK MAP kinase signaling plays a pivotal role in diverse cellular functions, including cell proliferation, differentiation, migration and survival. One of the central questions concerning this signaling is how activation of the same protein kinase, ERK, elicits distinct cellular outcomes. Recent progress has demonstrated that differences in the duration, magnitude and subcellular compartmentalization of ERK activity generate variations in signaling output that regulate cell fate decisions. Furthermore, several molecules have been identified as spatial, temporal or strength-controlling regulators of ERK activity. Signaling by various extracellular stimuli thus could be modulated by these regulators to give qualitative and quantitative differences in ERK activity, which are then interpreted by the cells as determinants for appropriate responses.
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Affiliation(s)
- Miki Ebisuya
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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202
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Marenda DR, Vrailas AD, Rodrigues AB, Cook S, Powers MA, Lorenzen JA, Perkins LA, Moses K. MAP kinase subcellular localization controls both pattern and proliferation in the developing Drosophila wing. Development 2006; 133:43-51. [PMID: 16308331 PMCID: PMC2032010 DOI: 10.1242/dev.02168] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) phosphorylate target proteins in both the cytoplasm and nucleus, and a strong correlation exists between the subcellular localization of MAPK and resulting cellular responses. It was thought that MAPK phosphorylation was always followed by rapid nuclear translocation. However, we and others have found that MAPK phosphorylation is not always sufficient for nuclear translocation in vivo. In the developing Drosophila wing, MAPK-mediated signaling is required both for patterning and for cell proliferation, although the mechanism of this differential control is not fully understood. Here, we show that phosphorylated MAPK (pMAPK) is held in the cytoplasm in differentiating larval and pupal wing vein cells, and we show that this cytoplasmic hold is required for vein cell fate. At the same time, we show that MAPK does move into the nucleus of other wing cells where it promotes cell proliferation. We propose a novel Ras pathway bifurcation in Drosophila and our results suggest a mechanism by which MAPK phosphorylation can signal two different cellular outcomes (differentiation versus proliferation) based on the subcellular localization of MAPK.
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Affiliation(s)
- Daniel R. Marenda
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Alysia D. Vrailas
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Aloma B. Rodrigues
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Summer Cook
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Maureen A. Powers
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - James A. Lorenzen
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Harvard Medical School Boston, MA 02114, USA
- Department of Pediatric Gastroenterology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Lizabeth A. Perkins
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Harvard Medical School Boston, MA 02114, USA
| | - Kevin Moses
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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203
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Kolch W. Coordinating ERK/MAPK signalling through scaffolds and inhibitors. Nat Rev Mol Cell Biol 2005; 6:827-37. [PMID: 16227978 DOI: 10.1038/nrm1743] [Citation(s) in RCA: 826] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The pathway from Ras through Raf and MEK (MAPK and ERK kinase) to ERK/MAPK (extracellular signal-regulated kinase/mitogen-activated protein kinase) regulates many fundamental cellular processes. Recently, a number of scaffolding proteins and endogenous inhibitors have been identified, and their important roles in regulating signalling through this pathway are now emerging. Some scaffolds augment the signal flux, but also mediate crosstalk with other pathways; certain adaptors target MEK-ERK/MAPK complexes to subcellular localizations; others provide regulated inhibition. Computational modelling indicates that, together, these modulators can determine the dynamic biological behaviour of the pathway.
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Affiliation(s)
- Walter Kolch
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
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204
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Callaway K, Rainey MA, Dalby KN. Quantifying ERK2–protein interactions by fluorescence anisotropy: PEA-15 inhibits ERK2 by blocking the binding of DEJL domains. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1754:316-23. [PMID: 16324895 DOI: 10.1016/j.bbapap.2005.11.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
While mitogen-activated protein kinase signaling pathways constitute highly regulated networks of protein-protein interactions, little quantitative information for these interactions is available. Here we highlight recent fluorescence anisotropy binding studies that focus on the interactions of ERK1 and ERK2 with PEA-15 (antiapoptotic phosphoprotein enriched in astrocytes-15 kDa), a small protein that sequesters ERK2 in the cytoplasm. The regulation of ERK2 by PEA-15 is appraised in the light of a simple equilibrium-binding model for reversible ERK2 nucleoplasmic-cytoplasmic shuttling, which elaborates on the theory of Burack and Shaw (J. Biol. Chem. 280, 3832-3837; 2005). Also highlighted is the recent observation that the peptide N-QKGKPRDLELPLSPSL-C, derived from the docking site for ERK/JNK and LEL (DEJL) in Elk-1, displaces PEA-15 from ERK2. It is proposed that the C-terminus of PEA-15 ((121)LXLXXXXKK(129)) is a reverse DEJL domain [which has a general consensus of R/K-phi(A)-X(3/4)-phi(B), where phi(A) and phi(B) are hydrophobic residues (Leu, Ile, or Val)], which mediates one arm of a bidentate PEA-15 interaction with ERK2. The notion that PEA-15 is a potent inhibitor of many ERK2-mediated phosphorylations, by virtue of its ability to block ERK2-DEJL domain interactions, is proposed.
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Affiliation(s)
- Kari Callaway
- Graduate Program in Biochemistry, University of Texas at Austin, TX 78712, USA
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205
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Li TS, Li XN, Chang ZJ, Fu XY, Liu L. Identification and functional characterization of a novel interleukin 17 receptor: a possible mitogenic activation through ras/mitogen-activated protein kinase signaling pathway. Cell Signal 2005; 18:1287-98. [PMID: 16310341 DOI: 10.1016/j.cellsig.2005.10.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 10/05/2005] [Indexed: 01/23/2023]
Abstract
Interleukin-17 receptor (IL-17R) is increasingly emerged as a distinct receptor family functioning in diverse cellular processes including inflammation and cancer. In this study, we uncovered a novel member of IL-17R from mouse tissue that was named mouse IL-17RE (mIL-17R). Mouse IL-17RE cDNA is composed of at least 14 exons and presents at least 6 spliced isoforms (mIL-17RE1-6) with a molecular weight ranging from 34.2 to 70.1 kD. Mouse IL-17RE is expressed in limited tissues such as lung, kidney, stomach, intestine and testis, etc., and is mainly localized in the cytoplasm and on cell membrane. IL-17RE can also be detected in numerous tumor cell lines. Importantly, a mitogenic effect was detected in BaF3 cells stably transfected with the chimeric receptor fused by the ectodomain of erythropoietin receptor (EPOR) with the transmembrane and endomain of IL-17RE in a serum-dependent but EPO-independent manner. Moreover, ERK1/2 phosphorylation was significantly up-regulated as the dose of mIL-17RE increased. Specific RNAi targeting at mIL-17RE dramatically inhibited the activation of ERK1/2, indicating that mIL-17RE could functionally activate RAS/MAPK signaling pathway. Using dominant negative MEK (Dn-MEK) or RAS (Dn-RAS) as a signaling blocker, we were able to show that mIL-17RE probably activated RAS/MAPK signaling at or upstream of RAS. Overall, our results strongly indicate that mIL-17RE may belong to a novel growth-receptor like molecule that has the capability to support cellular mitogenesis through RAS/MAPK pathway.
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Affiliation(s)
- Tie-Shi Li
- Tsinghua Institute of Genome Research, Department of Biological Sciences and Biotechnology and Institute of Biomedicine, Tsinghua University, Beijing 100084, China
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206
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Abstract
IQGAP1 modulates many cellular functions such as cell-cell adhesion, transcription, cytoskeletal architecture, and selected signaling pathways. We previously documented that IQGAP1 binds extracellular signal-regulated kinase (ERK) 2 and regulates growth factor-stimulated ERK activity. Here we show that MEK, the molecule immediately upstream of ERK in the Ras/mitogen-activated protein (MAP) kinase signaling cascade, also interacts directly with IQGAP1. Both MEK1 and MEK2 bound IQGAP1 in vitro and coimmunoprecipitated with IQGAP1. The addition of ERK2 enhanced by fourfold the in vitro interaction of MEK2 with IQGAP1 without altering binding of MEK1. Similarly, ERK1 promoted MEK binding to IQGAP1, but either MEK protein altered the association between IQGAP1 and ERK. Epidermal growth factor (EGF) differentially regulated binding, enhancing MEK1 interaction while reducing MEK2 binding to IQGAP1. In addition, both knockdown and overexpression of IQGAP1 reduced EGF-stimulated activation of MEK and ERK. Analyses with selective IQGAP1 mutant constructs indicated that MEK binding is crucial for IQGAP1 to modulate EGF activation of ERK. Our data strongly suggest that IQGAP1 functions as a molecular scaffold in the Ras/MAP kinase pathway.
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Affiliation(s)
- Monideepa Roy
- Brigham and Women's Hospital, Thorn 530, 75 Francis Street, Boston, MA 02115, USA
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207
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Thisse B, Thisse C. Functions and regulations of fibroblast growth factor signaling during embryonic development. Dev Biol 2005; 287:390-402. [PMID: 16216232 DOI: 10.1016/j.ydbio.2005.09.011] [Citation(s) in RCA: 374] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 07/29/2005] [Accepted: 09/05/2005] [Indexed: 11/28/2022]
Abstract
Fibroblast growth factors (FGF) are secreted molecules which function through the activation of specific tyrosine kinases receptors, the FGF receptors that transduce the signal by activating different pathways including the Ras/MAP kinase and the phospholipase-C gamma pathways. FGFs are involved in the regulation of many developmental processes including patterning, morphogenesis, differentiation, cell proliferation or migration. Such a diverse set of activities requires a tight control of the transduction signal which is achieved through the induction of different feedback inhibitors such as the Sproutys, Sef and MAP kinase phosphatase 3 which are responsible for the attenuation of FGF signals, limiting FGF activities in time and space.
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Affiliation(s)
- Bernard Thisse
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, CNRS/INSERM/ULP, 1 rue Laurent Fries, BP 10142, CU de Strasbourg, 67404 ILLKIRCH cedex, France
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208
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Echevarria D, Belo JA, Martinez S. Modulation of Fgf8 activity during vertebrate brain development. ACTA ACUST UNITED AC 2005; 49:150-7. [PMID: 16111545 DOI: 10.1016/j.brainresrev.2004.12.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Accepted: 12/16/2004] [Indexed: 11/19/2022]
Abstract
In recent years much emphasis has been placed on investigation of the precise control of FGF signaling during brain development. Such control is achieved in part by regulatory elements that determine the domains and levels of expression of genes coding for the diverse FGF ligands via specific molecular signaling pathways. There is new knowledge on the operation of such mechanisms in regions of the neural tube involved in the correct patterning of adjacent territories (known as secondary organizers of neural tube pattern). In the present minireview we intend to summarize recent evidence and emerging conclusions on potent modulators that govern the activity of Fgf8 signals in the developing vertebrate brain, focusing our attention on the best known secondary organizer, the isthmic organizer.
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Affiliation(s)
- Diego Echevarria
- Institute of Neuroscience, University Miguel Hernandez (UMH-CSIC), Carretera de Valencia (N332), San Juan, Alicante 03550, Spain.
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209
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Ghanekar Y, Lowe M. Protein kinase D: activation for Golgi carrier formation. Trends Cell Biol 2005; 15:511-4. [PMID: 16109486 DOI: 10.1016/j.tcb.2005.08.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 07/29/2005] [Accepted: 08/10/2005] [Indexed: 11/21/2022]
Abstract
Protein kinase D regulates fission at the trans-Golgi network (TGN) of transport carriers that deliver cargo to the plasma membrane. PKD is first recruited to the TGN through interaction with diacylglycerol and is subsequently activated by phosphorylation to promote carrier fission. In a recent study, the relevant upstream kinase at the TGN was identified as the novel protein kinase C isoform PKCeta, which in turn is activated in response to heterotrimeric G-protein activation. These findings indicate the existence of a kinase signaling cascade at the TGN that regulates carrier fission and suggest a mechanism by which cargo might direct the formation of its transport carriers.
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Affiliation(s)
- Yashoda Ghanekar
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, UK
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210
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Lawrie A, Spiekerkoetter E, Martinez EC, Ambartsumian N, Sheward WJ, MacLean MR, Harmar AJ, Schmidt AM, Lukanidin E, Rabinovitch M. Interdependent Serotonin Transporter and Receptor Pathways Regulate S100A4/Mts1, a Gene Associated With Pulmonary Vascular Disease. Circ Res 2005; 97:227-35. [PMID: 16002749 DOI: 10.1161/01.res.0000176025.57706.1e] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Heightened expression of the S100 calcium–binding protein, S100A4/Mts1, is observed in pulmonary vascular disease. Loss of serotonin (5-hydroxytryptamine [5-HT]) receptors or of the serotonin transporter (SERT) attenuates pulmonary hypertension in animals, and polymorphisms causing gain of SERT function are linked to clinical pulmonary vascular disease. Because 5-HT induces release of S100β, we investigated the codependence of 5-HT receptors and SERT in regulating S100A4/Mts1 in human pulmonary artery smooth muscle cells (hPA-SMC). 5-HT elevated S100A4/Mts1 mRNA levels and increased S100A4/Mts1 protein in hPA-SMC lysates and culture media. S100A4/Mts1 in the culture media stimulated proliferation and migration of hPA-SMC in a manner dependent on the receptor for advanced glycation end products. Treatment with SB224289 (selective antagonist of 5-HT
1B
), fluoxetine (SERT inhibitor), SERT RNA-interference, and iproniazid (monoamine oxidase-A inhibitor), blocked 5-HT–induced S100A4/Mts1. 5-HT signaling mediated phosphorylation (p) of extracellular signal–regulated kinase 1/2 (pERK1/2), but pERK1/2 nuclear translocation depended on SERT, monoamine oxidase activity, and reactive oxygen species. Nuclear translocation of pERK1/2 was required for pGATA-4–mediated transcription of S100A4/Mts1. These data provide evidence for a mechanistic link between the 5-HT pathway and S100A4/Mts1 in pulmonary hypertension and explain how the 5-HT
1B
receptor and SERT are codependent in regulating S100A4/Mts1.
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Affiliation(s)
- Allan Lawrie
- Department of Pediatrics, Stanford University School of Medicine, CCSR Rm 2245B, 269 Campus Dr, Stanford, CA 93405-5162, USA
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211
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Pullikuth A, McKinnon E, Schaeffer HJ, Catling AD. The MEK1 scaffolding protein MP1 regulates cell spreading by integrating PAK1 and Rho signals. Mol Cell Biol 2005; 25:5119-33. [PMID: 15923628 PMCID: PMC1140582 DOI: 10.1128/mcb.25.12.5119-5133.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
How the extracellular signal-regulated kinase (ERK) cascade regulates diverse cellular functions, including cell proliferation, survival, and motility, in a context-dependent manner remains poorly understood. Compelling evidence indicates that scaffolding molecules function in yeast to channel specific signals through common components to appropriate targets. Although a number of putative ERK scaffolding proteins have been identified in mammalian systems, none has been linked to a specific biological response. Here we show that the putative scaffold protein MEK partner 1 (MP1) and its partner p14 regulate PAK1-dependent ERK activation during adhesion and cell spreading but are not required for ERK activation by platelet-derived growth factor. MP1 associates with active but not inactive PAK1 and controls PAK1 phosphorylation of MEK1. Our data further show that MP1, p14, and MEK1 serve to inhibit Rho/Rho kinase functions necessary for the turnover of adhesion structures and cell spreading and reveal a signal-channeling function for a MEK1/ERK scaffold in orchestrating cytoskeletal rearrangements important for cell motility.
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Affiliation(s)
- Ashok Pullikuth
- Department of Pharmacology, Louisiana State University Health Sciences Center, 1901 Perdido Street, New Orleans, LA 70112, USA
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212
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Lin W, Jing N, Basson MA, Dierich A, Licht J, Ang SL. Synergistic activity of Sef and Sprouty proteins in regulating the expression of Gbx2 in the mid-hindbrain region. Genesis 2005; 41:110-5. [PMID: 15729686 DOI: 10.1002/gene.20103] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Sef and Sprouty proteins function as feedback antagonists of fibroblast growth factor (Fgf) signaling in zebrafish embryos. To study the role of Sef in mice, we generated Sef homozygous mutant animals. These animals are viable and show normal expression of mid-hindbrain genes at embryonic days 8.5 and 9.5. To investigate the possibility of functional synergism between Sef and Sprouty proteins, we electroporated Sprouty2(Y55A), which functions in a dominant-negative manner in tissue culture cells into the mid-hindbrain region of wildtype and Sef mutant embryos. The expression pattern of Gbx2, a downstream target of Fgf signaling, was expanded or shifted in electroporated embryos, and this effect was significantly enhanced in the Sef mutant background. Altogether, our results demonstrate that Sef and Sproutys function synergistically to regulate Gbx2 expression in the anterior hindbrain.
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Affiliation(s)
- Wei Lin
- Medical Research Council, National Institute for Medical Research, London, UK
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213
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Coogan AN, Piggins HD. Dark pulse suppression of P-ERK and c-Fos in the hamster suprachiasmatic nuclei. Eur J Neurosci 2005; 22:158-68. [PMID: 16029205 DOI: 10.1111/j.1460-9568.2005.04193.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is well-established that light pulses regulate components of the extracellular signal-regulated kinases I/II (ERK) cascade in the suprachiasmatic nuclei (SCN) circadian clock. These events are important for photic-resetting of the circadian clock. The SCN circadian clock is also reset by pulses of dark, but it is unknown if this stimulus alters the activity of ERK, the transcription factor Elk-1 or expression of the immediate early gene c-fos in the SCN. Using Syrian hamsters free-running in constant light, we determined the effects of dark pulses on these factors in the SCN. In constant light, levels of phosphorylated ERK (P-ERK) showed significant circadian variation in the Syrian hamster SCN, while levels of c-Fos or phosphorylated Elk-1 (P-Elk-1) did not. A 6-h dark pulse beginning at circadian time (CT) 8 down-regulated expression of P-ERK and c-Fos, but not P-Elk-1, in the SCN. Following termination of the pulse, levels of c-Fos increased above time-matched control values, while P-ERK expression did not. When given at the beginning of the subjective night (CT13), a 6-h dark pulse did not phase-shift behavioural rhythms and failed to alter the expression of c-Fos, P-ERK, or P-Elk-1 in the SCN. At the level of the visual thalamus, expression of c-Fos in the intergeniculate leaflet was higher during the subjective night as compared to the subjective day, although dark pulses had no robust effects on expression of c-Fos or P-ELK-1 in this structure. We conclude that dark-pulse resetting of the circadian clock is complex and involves both non-photic and photic components.
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Affiliation(s)
- Andrew N Coogan
- 3.614 Stopford Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
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214
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Plowman SJ, Hancock JF. Ras signaling from plasma membrane and endomembrane microdomains. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1746:274-83. [PMID: 16039730 DOI: 10.1016/j.bbamcr.2005.06.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 05/30/2005] [Accepted: 06/10/2005] [Indexed: 11/29/2022]
Abstract
Ras proteins are compartmentalized by dynamic interactions with both plasma membrane microdomains and intracellular membranes. The mechanisms underlying Ras compartmentalization involve a series of protein/lipid, lipid/lipid and cytoskeleton interactions, resulting in the generation of discrete microdomains from which Ras operates. Segregation of Ras proteins to these different platforms regulates the formation of Ras signaling complexes and the generation of discrete signal outputs. This temporal and spatial modulation of Ras signal transduction provides a mechanism for the generation of different biological outcomes from different Ras isoforms, as well as flexibility in the signal output from a single activated isoform.
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Affiliation(s)
- S J Plowman
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, QLD 4072, Australia
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215
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216
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Yoshimura SI, Yoshioka K, Barr FA, Lowe M, Nakayama K, Ohkuma S, Nakamura N. Convergence of Cell Cycle Regulation and Growth Factor Signals on GRASP65. J Biol Chem 2005; 280:23048-56. [PMID: 15834132 DOI: 10.1074/jbc.m502442200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Together with other Golgi matrix components, GRASP65 contributes to the stacking of Golgi cisternae in interphase cells. During mitosis, GRASP65 is heavily phosphorylated, and in turn, cisternal stacking is inhibited leading to the breakdown of the Golgi apparatus. Here we show that GRASP65 is phosphorylated on serine 277 in interphase cells, and this is strongly enhanced in response to the addition of serum or epidermal growth factor. This is directly mediated by ERK suggesting that GRASP65 has some role in growth factor signal transduction. Phosphorylation of Ser-277 is also dramatically increased during mitosis, however this is mediated by Cdk1 and not by ERK. The microinjection of recombinant GRASP65 without N-terminal myristoylation or a peptide fragment containing Ser-277 into the cytosol of normal rat kidney cells inhibits passage through mitosis. This effect is abolished when Ser-277 is replaced with alanine suggesting the phosphorylation of Ser-277 plays an important role in cell cycle regulation. The convergence of cell cycle regulation and growth factor signals on GRASP65 Ser-277 suggests that GRASP65 may function as a signal integrator controlling the cell growth.
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Affiliation(s)
- Shin-ichiro Yoshimura
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Japan
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217
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Herbert SP, Ponnambalam S, Walker JH. Cytosolic phospholipase A2-alpha mediates endothelial cell proliferation and is inactivated by association with the Golgi apparatus. Mol Biol Cell 2005; 16:3800-9. [PMID: 15930125 PMCID: PMC1182317 DOI: 10.1091/mbc.e05-02-0164] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Arachidonic acid and its metabolites are implicated in regulating endothelial cell proliferation. Cytosolic phospholipase A2-alpha (cPLA2alpha) is responsible for receptor-mediated arachidonic acid evolution. We tested the hypothesis that cPLA2alpha activity is linked to endothelial cell proliferation. The specific cPLA2alpha inhibitor, pyrrolidine-1, inhibited umbilical vein endothelial cell (HUVEC) proliferation in a dose-dependent manner. Exogenous arachidonic acid addition reversed this inhibitory effect. Inhibition of sPLA2 did not affect HUVEC proliferation. The levels of cPLA2alpha did not differ between subconfluent and confluent cultures of cells. However, using fluorescence microscopy we observed a novel, confluence-dependent redistribution of cPLA2alpha to the distal Golgi apparatus in HUVECs. Association of cPLA2alpha with the Golgi was linked to the proliferative status of HUVECs. When associated with the Golgi apparatus, cPLA2alpha activity was seen to be 87% inhibited. Relocation of cPLA2alpha to the cytoplasm and nucleus, and cPLA2alpha enzyme activity were required for cell cycle entry upon mechanical wounding of confluent monolayers. Thus, cPLA2alpha activity and function in controlling endothelial cell proliferation is regulated by reversible association with the Golgi apparatus.
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Affiliation(s)
- S P Herbert
- School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, United Kingdom
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218
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Yin G, Zheng Q, Yan C, Berk BC. GIT1 is a scaffold for ERK1/2 activation in focal adhesions. J Biol Chem 2005; 280:27705-12. [PMID: 15923189 DOI: 10.1074/jbc.m502271200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GIT1 (G protein-coupled receptor kinase-interacting protein 1) has been shown to regulate focal adhesion disassembly. We previously reported that GIT1 associates with MEK1 and acts as a scaffold to enhance ERK1/2 activation. Here, we show that GIT1 co-localizes with ERK1/2 in focal adhesions and regulates cell migration in vascular smooth muscle cells, HEK293 cells, and HeLa cells. Immunofluorescence showed that GIT1 co-localized with phospho-ERK1/2 in focal adhesions after epidermal growth factor stimulation. Because Src is required for both GIT1 tyrosine phosphorylation and focal adhesion disassembly, we studied the effects of Src on GIT1-ERK1/2 interactions. PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine) inhibited association of GIT1 with ERK1/2, and their co-localization in focal adhesions was dramatically decreased in SYF-/- cells. GIT1 small interfering RNA significantly inhibited ERK1/2 recruitment to and activation in focal adhesions. GIT1 small interfering RNA and mutated GIT1 lacking the MEK1 binding domain significantly decreased epidermal growth factor-stimulated cell spreading and migration, suggesting that GIT1-mediated events such as ERK1/2 activation are required for spreading and migration. In summary, the present study further supports a key role for GIT1 (a MEK1-binding protein) as a scaffold for signal transduction in focal adhesions.
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Affiliation(s)
- Guoyong Yin
- Center for Cardiovascular Research and Department of Medicine, University of Rochester, Rochester, New York 14642, USA
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219
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Kondoh K, Torii S, Nishida E. Control of MAP kinase signaling to the nucleus. Chromosoma 2005; 114:86-91. [PMID: 15902482 DOI: 10.1007/s00412-005-0341-9] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 03/22/2005] [Accepted: 03/22/2005] [Indexed: 12/01/2022]
Abstract
MAP kinase (MAPK) signaling is among central signaling pathways that regulate cell proliferation, cell differentiation and apoptosis. As MAPK should transmit extracellular signals to proper regions or compartments in cells, controlling subcellular localization of MAPK is important for regulating fidelity and specificity of MAPK signaling. The ERK1/2-type of MAPK is the best characterized member of the MAPK family. In response to extracellular stimulus, ERK1/2 translocates from the cytoplasm to the nucleus by passing through the nuclear pore by several independent mechanisms. Sef (similar expression to fgf genes), a transmembrane protein, has been shown to be a regulator of subcellular distribution of ERK1/2. Sef binds to activated MEK1/2, the specific activator of ERK1/2, and tethers the activated MEK1/2/activated ERK1/2 complex to the Golgi apparatus and the plasma membrane. Thus, Sef blocks ERK1/2 signaling to the nucleus and allows signaling to the cytoplasm. Here we review recent findings on spatial regulation of MAPK, especially on nucleocytoplasmic trafficking of ERK1/2.
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Affiliation(s)
- Kunio Kondoh
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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220
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221
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Affiliation(s)
- Doris Meder
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
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222
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Mandl M, Slack DN, Keyse SM. Specific inactivation and nuclear anchoring of extracellular signal-regulated kinase 2 by the inducible dual-specificity protein phosphatase DUSP5. Mol Cell Biol 2005; 25:1830-45. [PMID: 15713638 PMCID: PMC549372 DOI: 10.1128/mcb.25.5.1830-1845.2005] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 09/24/2004] [Accepted: 11/30/2004] [Indexed: 11/20/2022] Open
Abstract
The mechanisms which determine the nuclear accumulation and inactivation of the extracellular signal-regulated kinase 1 (ERK1) or ERK2 mitogen-activated protein (MAP) kinases are poorly understood. Here we demonstrate that DUSP5, an inducible nuclear phosphatase, interacts specifically with ERK2 via a kinase interaction motif (KIM) within its amino-terminal noncatalytic domain. This binding determines the substrate specificity of DUSP5 in vivo, as it inactivates ERK2 but not Jun N-terminal protein kinase or p38 MAP kinase. Using green fluorescent protein fusions, we identify within this same domain of DUSP5 a functional nuclear localization signal (NLS) which functions independently of the KIM. Moreover, we demonstrate that the expression of DUSP5 causes both nuclear translocation and sequestration of inactive ERK2. Nuclear anchoring is ERK2 specific and requires both interactions between the DUSP5 KIM and the common docking site of ERK2 and a functional NLS within DUSP5. Finally, the expression of a catalytically inactive mutant of DUSP5 also tethers ERK2 within the nucleus. Furthermore, this nuclear ERK2 is phosphorylated by MAP kinase kinase in response to growth factors and also activates transcription factor Elk-1. We conclude that DUSP5 is an inducible nuclear ERK-specific MAP kinase phosphatase that functions as both an inactivator of and a nuclear anchor for ERK2 in mammalian cells. In addition, our data indicate that the cytoplasm may not be an exclusive site of MAP kinase activation.
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Affiliation(s)
- Margret Mandl
- Cancer Research UK, Molecular Pharmacology Unit, Biomedical Research Centre, Level 5, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland, United Kingdom
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Rocks O, Peyker A, Kahms M, Verveer PJ, Koerner C, Lumbierres M, Kuhlmann J, Waldmann H, Wittinghofer A, Bastiaens PIH. An acylation cycle regulates localization and activity of palmitoylated Ras isoforms. Science 2005; 307:1746-52. [PMID: 15705808 DOI: 10.1126/science.1105654] [Citation(s) in RCA: 667] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We show that the specific subcellular distribution of H- and Nras guanosine triphosphate-binding proteins is generated by a constitutive de/reacylation cycle that operates on palmitoylated proteins, driving their rapid exchange between the plasma membrane (PM) and the Golgi apparatus. Depalmitoylation redistributes farnesylated Ras in all membranes, followed by repalmitoylation and trapping of Ras at the Golgi, from where it is redirected to the PM via the secretory pathway. This continuous cycle prevents Ras from nonspecific residence on endomembranes, thereby maintaining the specific intracellular compartmentalization. The de/reacylation cycle also initiates Ras activation at the Golgi by transport of PM-localized Ras guanosine triphosphate. Different de/repalmitoylation kinetics account for isoform-specific activation responses to growth factors.
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Affiliation(s)
- Oliver Rocks
- Department of Structural Biology, Max Planck Institute for Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
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Abstract
Fibroblast growth factors (FGFs) have been implicated in diverse cellular processes including apoptosis, cell survival, chemotaxis, cell adhesion, migration, differentiation, and proliferation. This review presents our current understanding on the roles of FGF signaling, the pathways employed, and its regulation. We focus on FGF signaling during early embryonic processes in vertebrates, such as induction and patterning of the three germ layers as well as its function in the control of morphogenetic movements.
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Affiliation(s)
- Ralph T Böttcher
- Division of Molecular Embryology, Deutsches Krebsforschungszentrum, D-69120 Heidelberg, Germany.
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225
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Abstract
The subcellular localization of transmembrane receptors and other signaling proteins has emerged as a key component in the regulation of the intensity and specificity of their activity. Recent research indicates that immature TrkA neurotrophin receptors are transactivated in the Golgi apparatus after stimulation of neuropeptide pituitary adenylate cyclase-activating polypeptide PAC1 receptors or adenosine A(2A) receptors. Transactivation occurs independently of the TrkA extracellular ligand, nerve growth factor (NGF), through a signaling pathway that is distinct from that used in the transactivation of other receptor tyrosine kinases and has consequences distinct from those elicited by NGF at the plasma membrane.
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Kostenko EV, Mahon GM, Cheng L, Whitehead IP. The Sec14 Homology Domain Regulates the Cellular Distribution and Transforming Activity of the Rho-specific Guanine Nucleotide Exchange Factor Dbs. J Biol Chem 2005; 280:2807-17. [PMID: 15531584 DOI: 10.1074/jbc.m411139200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Dbs is a Rho-specific guanine nucleotide exchange factor that was identified in a screen for proteins whose overexpression cause deregulated growth in murine fibroblasts. Dbs contains multiple recognizable motifs including a centrally located Rho-specific guanine nucleotide exchange factor domain, a COOH-terminal Src homology 3 domain, two spectrin-like repeats, and a recently identified NH(2)-terminal Sec14 homology domain. The transforming potential of Dbs is substantially activated by the removal of inhibitory sequences that lie outside of the core catalytic sequences, and in this current study we mapped this inhibition to the Sec14 domain. Surprisingly removal of the NH(2) terminus did not alter the catalytic activity of Dbs in vivo but rather altered its subcellular distribution. Whereas full-length Dbs was distributed primarily in a perinuclear structure that coincides with a marker for the Golgi apparatus, removal of the Sec14 domain was associated with translocation of Dbs to the cell periphery where it accumulated within membrane ruffles and lamellipodia. However, translocation of Dbs and the concomitant changes in the actin cytoskeleton were not sufficient to fully activate Dbs transformation. The Sec14 domain also forms intramolecular contacts with the pleckstrin homology domain, and these contacts must also be relieved to achieve full transforming activity. Collectively these observations suggest that the Sec14 domain regulates Dbs transformation through at least two distinct mechanisms, neither of which appears to directly influence the in vivo exchange activity of the protein.
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Affiliation(s)
- Elena V Kostenko
- Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07103, USA
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227
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Rubin C, Gur G, Yarden Y. Negative regulation of receptor tyrosine kinases: unexpected links to c-Cbl and receptor ubiquitylation. Cell Res 2005; 15:66-71. [PMID: 15686631 DOI: 10.1038/sj.cr.7290268] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Intracellular signals mediated by the family of receptor tyrosine kinases play pivotal roles in morphogenesis, cell fate determination and pathogenesis. Precise control of signal amplitude and duration is critical for the fidelity and robustness of these processes. Activation of receptor tyrosine kinases by their cognate growth factors not only leads to propagation of the signal through various biochemical cascades, but also sets in motion multiple attenuation mechanisms that ultimately terminate the active state. Early attenuators pre-exist prior to receptor activation and they act to limit signal propagation. Subsequently, late attenuators, such as Lrig and Sprouty, are transcriptionally induced and further act to dampen the signal. Central to the process of signaling attenuation is the role of the E3 ubiquitin ligase c-Cbl. While Cbl-mediated processes of receptor ubiquitylation and endocytosis are relatively well understood, the links of Cbl to other negative regulators are just now beginning to be appreciated. Here we review some emerging interfaces between Cbl and the transcriptionally induced negative regulators Lrig and Sprouty.
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Affiliation(s)
- Chanan Rubin
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 76100, Israel
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228
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Plotkin LI, Aguirre JI, Kousteni S, Manolagas SC, Bellido T. Bisphosphonates and estrogens inhibit osteocyte apoptosis via distinct molecular mechanisms downstream of extracellular signal-regulated kinase activation. J Biol Chem 2004; 280:7317-25. [PMID: 15590626 DOI: 10.1074/jbc.m412817200] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Both estrogens and bisphosphonates attenuate osteocyte apoptosis by activating the extracellular signal-regulated kinases (ERKs). However, whereas estrogens activate ERKs via an extranuclear function of the estrogen receptor, bisphosphonates do so by opening connexin 43 hemichannels. Here, we demonstrated that the signaling events downstream of ERKs induced by these two stimuli are also distinct. Inhibition of osteocyte apoptosis by estrogens requires nuclear accumulation of ERKs and activation of downstream transcription factors. On the other hand, anti-apoptosis induced by bisphosphonates requires neither transcription nor ERK-dependent transcription factors. Instead, the effect of bisphosphonates is abolished when ERKs are restricted to the nucleus by blocking CRM1/exportin1-mediated nuclear protein export or by expressing nuclear-anchored ERKs, but it is unaffected in cells expressing cytoplasmic-anchored ERKs. Connexin 43/ERK-mediated anti-apoptosis induced by bisphosphonates requires the kinase activity of the cytoplasmic target of ERKs, p90(RSK), which in turn phosphorylates the pro-apoptotic protein BAD and C/EBPbeta. Phosphorylation of BAD renders it inactive, whereas phosphorylation of C/EBPbeta leads to binding of pro-caspases, thus inhibiting apoptosis independently of the transcriptional activity of this transcription factor. Consistent with the evidence that estrogens and bisphosphonates phosphorylate diverse targets of ERKs, probably resulting from activation of spatially distinct pools of these kinases, the two agents had additive effects on osteocyte survival.
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Affiliation(s)
- Lilian I Plotkin
- Division of Endocrinology and Metabolism, the Center for Osteoporosis and Metabolic Bone Diseases, the Central Arkansas Veterans Affairs Healthcare System, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199, USA
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Akgoz M, Kalyanaraman V, Gautam N. Receptor-mediated reversible translocation of the G protein betagamma complex from the plasma membrane to the Golgi complex. J Biol Chem 2004; 279:51541-4. [PMID: 15448129 DOI: 10.1074/jbc.m410639200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heterotrimeric G proteins have been thought to function on the plasma membrane after activation by transmembrane receptors. Here we show that, after activation by receptors, the G protein betagamma complex selectively translocates to the Golgi. Receptor inactivation results in Gbetagamma translocating back to the plasma membrane. Both translocation processes occur rapidly within seconds. The efficiency of translocation is influenced by the type of gamma subunit present in the G protein. Distinctly different receptor types are capable of inducing the translocation. Receptor-mediated translocation of Gbetagamma can spatially segregate G protein signaling activity.
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Affiliation(s)
- Muslum Akgoz
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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230
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Abstract
Subcellular compartmentalization is an emerging paradigm in signaling pathways including the Ras/MAPK pathway. In a recent issue of Developmental Cell, Torii et al. (2004) characterize a new MAPK scaffold, Sef, that resides on the Golgi apparatus, binds active MEK/ERK complexes, and permits signaling to cytosolic substrates but not nuclear targets.
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Affiliation(s)
- Mark R Philips
- NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
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