1
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Butt BG, Fischer D, Rep AR, Schauflinger M, Read C, Böck T, Hirner M, Wienen F, Graham SC, von Einem J. Human cytomegalovirus deploys molecular mimicry to recruit VPS4A to sites of virus assembly. PLoS Pathog 2024; 20:e1012300. [PMID: 38900818 PMCID: PMC11218997 DOI: 10.1371/journal.ppat.1012300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 07/02/2024] [Accepted: 05/28/2024] [Indexed: 06/22/2024] Open
Abstract
The AAA-type ATPase VPS4 is recruited by proteins of the endosomal sorting complex required for transport III (ESCRT-III) to catalyse membrane constriction and membrane fission. VPS4A accumulates at the cytoplasmic viral assembly complex (cVAC) of cells infected with human cytomegalovirus (HCMV), the site where nascent virus particles obtain their membrane envelope. Here we show that VPS4A is recruited to the cVAC via interaction with pUL71. Sequence analysis, deep-learning structure prediction, molecular dynamics and mutagenic analysis identify a short peptide motif in the C-terminal region of pUL71 that is necessary and sufficient for the interaction with VPS4A. This motif is predicted to bind the same groove of the N-terminal VPS4A Microtubule-Interacting and Trafficking (MIT) domain as the Type 2 MIT-Interacting Motif (MIM2) of cellular ESCRT-III components, and this viral MIM2-like motif (vMIM2) is conserved across β-herpesvirus pUL71 homologues. However, recruitment of VPS4A by pUL71 is dispensable for HCMV morphogenesis or replication and the function of the conserved vMIM2 during infection remains enigmatic. VPS4-recruitment via a vMIM2 represents a previously unknown mechanism of molecular mimicry in viruses, extending previous observations that herpesviruses encode proteins with structural and functional homology to cellular ESCRT-III components.
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Affiliation(s)
- Benjamin G. Butt
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Daniela Fischer
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
| | - Alison R. Rep
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | | | - Clarissa Read
- Central Facility for Electron Microscopy, Ulm University, Ulm, Germany
| | - Thomas Böck
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
| | - Manuel Hirner
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
| | - Frederik Wienen
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
| | - Stephen C. Graham
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Jens von Einem
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
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2
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Murthy MHS, Jasbi P, Lowe W, Kumar L, Olaosebikan M, Roger L, Yang J, Lewinski N, Daniels N, Cowen L, Klein-Seetharaman J. Insulin signaling and pharmacology in humans and in corals. PeerJ 2024; 12:e16804. [PMID: 38313028 PMCID: PMC10838073 DOI: 10.7717/peerj.16804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 12/27/2023] [Indexed: 02/06/2024] Open
Abstract
Once thought to be a unique capability of the Langerhans islets in the pancreas of mammals, insulin (INS) signaling is now recognized as an evolutionarily ancient function going back to prokaryotes. INS is ubiquitously present not only in humans but also in unicellular eukaryotes, fungi, worms, and Drosophila. Remote homologue identification also supports the presence of INS and INS receptor in corals where the availability of glucose is largely dependent on the photosynthetic activity of the symbiotic algae. The cnidarian animal host of corals operates together with a 20,000-sized microbiome, in direct analogy to the human gut microbiome. In humans, aberrant INS signaling is the hallmark of metabolic disease, and is thought to play a major role in aging, and age-related diseases, such as Alzheimer's disease. We here would like to argue that a broader view of INS beyond its human homeostasis function may help us understand other organisms, and in turn, studying those non-model organisms may enable a novel view of the human INS signaling system. To this end, we here review INS signaling from a new angle, by drawing analogies between humans and corals at the molecular level.
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Affiliation(s)
| | - Paniz Jasbi
- School of Molecular Sciences, Arizona State University, Phoenix, AZ, USA
| | - Whitney Lowe
- Departments of Chemistry & Physics, Colorado School of Mines, Golden, CO, United States
| | - Lokender Kumar
- Departments of Chemistry & Physics, Colorado School of Mines, Golden, CO, United States
| | | | - Liza Roger
- School of Molecular Sciences, Arizona State University, Phoenix, AZ, USA
- School of Ocean Futures, Arizona State University, Tempe, AZ, United States of America
| | - Jinkyu Yang
- Department of Aeronautics & Astronautics, University of Washington, Seattle, WA, USA
| | - Nastassja Lewinski
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Noah Daniels
- Department of Computer Science, University of Rhode Island, Kingston, RI, USA
| | - Lenore Cowen
- Department of Computer Science, Tufts University, Medford, MA, USA
| | - Judith Klein-Seetharaman
- School of Molecular Sciences, Arizona State University, Phoenix, AZ, USA
- Departments of Chemistry & Physics, Colorado School of Mines, Golden, CO, United States
- College of Health Solutions, Arizona State University, Phoenix, AZ, United States
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3
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Kim KM, Shin EJ, Yang JH, Ki SH. Integrative roles of sphingosine kinase in liver pathophysiology. Toxicol Res 2023; 39:549-564. [PMID: 37779595 PMCID: PMC10541397 DOI: 10.1007/s43188-023-00193-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/17/2023] [Accepted: 05/24/2023] [Indexed: 10/03/2023] Open
Abstract
Bioactive sphingolipids and enzymes that metabolize sphingolipid-related substances have been considered as critical messengers in various signaling pathways. One such enzyme is the crucial lipid kinase, sphingosine kinase (SphK), which mediates the conversion of sphingosine to the potent signaling substance, sphingosine-1-phosphate. Several studies have demonstrated that SphK metabolism is strictly regulated to maintain the homeostatic balance of cells. Here, we summarize the role of SphK in the course of liver disease and illustrate its effects on both physiological and pathological conditions of the liver. SphK has been implicated in a variety of liver diseases, such as steatosis, liver fibrosis, hepatocellular carcinoma, and hepatic failure. This study may advance the understanding of the cellular and molecular foundations of liver disease and establish therapeutic approaches via SphK modulation.
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Affiliation(s)
- Kyu Min Kim
- Department of Biomedical Science, College of Natural Science, Chosun University, Gwangju, 61452 Republic of Korea
| | - Eun Jin Shin
- Department of Biomedical Science, College of Natural Science, Chosun University, Gwangju, 61452 Republic of Korea
| | - Ji Hye Yang
- College of Korean Medicine, Dongshin University, Naju, Jeollanam-Do 58245 Republic of Korea
| | - Sung Hwan Ki
- College of Pharmacy, Chosun University, 309 Pilmun-Daero, Dong-Gu, Gwangju, 61452 Republic of Korea
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4
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Wenzel DM, Mackay DR, Skalicky JJ, Paine EL, Miller MS, Ullman KS, Sundquist WI. Comprehensive analysis of the human ESCRT-III-MIT domain interactome reveals new cofactors for cytokinetic abscission. eLife 2022; 11:e77779. [PMID: 36107470 PMCID: PMC9477494 DOI: 10.7554/elife.77779] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
The 12 related human ESCRT-III proteins form filaments that constrict membranes and mediate fission, including during cytokinetic abscission. The C-terminal tails of polymerized ESCRT-III subunits also bind proteins that contain Microtubule-Interacting and Trafficking (MIT) domains. MIT domains can interact with ESCRT-III tails in many different ways to create a complex binding code that is used to recruit essential cofactors to sites of ESCRT activity. Here, we have comprehensively and quantitatively mapped the interactions between all known ESCRT-III tails and 19 recombinant human MIT domains. We measured 228 pairwise interactions, quantified 60 positive interactions, and discovered 18 previously unreported interactions. We also report the crystal structure of the SPASTIN MIT domain in complex with the IST1 C-terminal tail. Three MIT enzymes were studied in detail and shown to: (1) localize to cytokinetic midbody membrane bridges through interactions with their specific ESCRT-III binding partners (SPASTIN-IST1, KATNA1-CHMP3, and CAPN7-IST1), (2) function in abscission (SPASTIN, KATNA1, and CAPN7), and (3) function in the 'NoCut' abscission checkpoint (SPASTIN and CAPN7). Our studies define the human MIT-ESCRT-III interactome, identify new factors and activities required for cytokinetic abscission and its regulation, and provide a platform for analyzing ESCRT-III and MIT cofactor interactions in all ESCRT-mediated processes.
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Affiliation(s)
- Dawn M Wenzel
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Douglas R Mackay
- Department of Oncological Sciences, Huntsman Cancer Institute, University of UtahSalt Lake CityUnited States
| | - Jack J Skalicky
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Elliott L Paine
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Matthew S Miller
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of UtahSalt Lake CityUnited States
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
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5
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Okada T, Nishida S, Zhang L, Ibrahim Mohamed NN, Wang T, Ijuin T, Kajimoto T, Nakamura SI. Constitutive activation of S1P receptors at the trans-Golgi network is required for surface transport carrier formation. iScience 2021; 24:103351. [PMID: 34805799 PMCID: PMC8590068 DOI: 10.1016/j.isci.2021.103351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 11/10/2022] Open
Abstract
The importance of the G-protein βγ subunits in the regulation of cargo transport from the trans-Golgi network (TGN) to the plasma membrane (PM) is well accepted; however, the molecular mechanism underlying the G-protein activation at the TGN remains unclear. We show here that sphingosine 1-phosphate (S1P) receptors at the PM were trafficked to the TGN in response to a surface transport cargo, temperature-sensitive vesicular stomatitis virus glycoprotein tagged with green fluorescent protein accumulation in the Golgi. The receptor internalization occurred in an S1P-independent manner but required phosphorylation by G-protein receptor kinase 2 and β-arrestin association before internalization. Continuously activated S1P receptors in a manner dependent on S1P at the TGN kept transmitting G-protein signals including the βγ subunits supply necessary for transport carrier formation at the TGN destined for the PM. S1P receptors traffic from the PM to Golgi in a surface cargo-dependent manner S1PR trafficking follows GRK2-dependent phosphorylation and β-arrestin binding S1PRs at the Golgi are continuously activated by S1P while sending G-protein signals S1PR/Gβγ signals at the Golgi are indispensable for surface transport carrier formation
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Affiliation(s)
- Taro Okada
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Susumu Nishida
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Lifang Zhang
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Nesma Nabil Ibrahim Mohamed
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.,Department of Agricultural Biochemistry, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
| | - Tianyou Wang
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Takeshi Ijuin
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Taketoshi Kajimoto
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Shun-Ichi Nakamura
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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6
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Venkatraman G, Tang X, Du G, Parisentti AM, Hemmings DG, Brindley DN. Lysophosphatidate Promotes Sphingosine 1-Phosphate Metabolism and Signaling: Implications for Breast Cancer and Doxorubicin Resistance. Cell Biochem Biophys 2021; 79:531-545. [PMID: 34415509 DOI: 10.1007/s12013-021-01024-6] [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: 06/23/2021] [Accepted: 07/09/2021] [Indexed: 10/20/2022]
Abstract
Lysophosphatidate (LPA) and sphingosine 1-phosphate (S1P) promote vasculogenesis, angiogenesis, and wound healing by activating a plethora of overlapping signaling pathways that stimulate mitogenesis, cell survival, and migration. As such, maladaptive signaling by LPA and S1P have major effects in increasing tumor progression and producing poor patient outcomes after chemotherapy and radiotherapy. Many signaling actions of S1P and LPA are not redundant; each are vital in normal physiology and their metabolisms differ. In the present work, we studied how LPA signaling impacts S1P metabolism and signaling in MDA-MB-231 and MCF-7 breast cancer cells. LPA increased sphingosine kinase-1 (SphK1) synthesis and rapidly activated cytosolic SphK1 through association with membranes. Blocking phospholipase D activity attenuated the LPA-induced activation of SphK1 and the synthesis of ABCC1 and ABCG2 transporters that secrete S1P from cells. This effect was magnified in doxorubicin-resistant MCF-7 cells. LPA also facilitated S1P signaling by increasing mRNA expression for S1P1 receptors. Doxorubicin-resistant MCF-7 cells had increased S1P2 and S1P3 receptor expression and show increased LPA-induced SphK1 activation, increased expression of ABCC1, ABCG2 and greater S1P secretion. Thus, LPA itself and LPA-induced S1P signaling counteract doxorubicin-induced death of MCF-7 cells. We conclude from the present and previous studies that LPA promotes S1P metabolism and signaling to coordinately increase tumor growth and metastasis and decrease the effectiveness of chemotherapy and radiotherapy for breast cancer treatment.
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Affiliation(s)
- Ganesh Venkatraman
- Department of Biochemistry, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Xiaoyun Tang
- Department of Biochemistry, University of Alberta, Edmonton, AB, T6G 2S2, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Guangwei Du
- Department of Integrative Biology & Pharmacology, University of Texas Health Science at Houston, Houston, TX, 77030, USA
| | - Amadeo M Parisentti
- Northern Ontario School of Medicine, Health Sciences North Research Institute, Sudbury, ON, P3E 2H2, Canada
| | - Denise G Hemmings
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, T6G 2S2, Canada.
- Medical Microbiology and Immunology, Obstetrics and Gynecology, Women and Children's Health Research Institute, Li Ka Shing Institute of Virology, Cardiovascular Research Center, University of Alberta, Edmonton, AB, T6G 2S2, Canada.
| | - David N Brindley
- Department of Biochemistry, University of Alberta, Edmonton, AB, T6G 2S2, Canada.
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, T6G 2S2, Canada.
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7
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Kervin TA, Wiseman BC, Overduin M. Phosphoinositide Recognition Sites Are Blocked by Metabolite Attachment. Front Cell Dev Biol 2021; 9:690461. [PMID: 34368138 PMCID: PMC8340361 DOI: 10.3389/fcell.2021.690461] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/18/2021] [Indexed: 12/16/2022] Open
Abstract
Membrane readers take part in trafficking and signaling processes by localizing proteins to organelle surfaces and transducing molecular information. They accomplish this by engaging phosphoinositides (PIs), a class of lipid molecules which are found in different proportions in various cellular membranes. The prototypes are the PX domains, which exhibit a range of specificities for PIs. Our meta-analysis indicates that recognition of membranes by PX domains is specifically controlled by modification of lysine and arginine residues including acetylation, hydroxyisobutyrylation, glycation, malonylation, methylation and succinylation of sidechains that normally bind headgroups of phospholipids including organelle-specific PI signals. Such metabolite-modulated residues in lipid binding elements are named MET-stops here to highlight their roles as erasers of membrane reader functions. These modifications are concentrated in the membrane binding sites of half of all 49 PX domains in the human proteome and correlate with phosphoregulatory sites, as mapped using the Membrane Optimal Docking Area (MODA) algorithm. As these motifs are mutated and modified in various cancers and the responsible enzymes serve as potential drug targets, the discovery of MET-stops as a widespread inhibitory mechanism may aid in the development of diagnostics and therapeutics aimed at the readers, writers and erasers of the PI code.
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Affiliation(s)
- Troy A Kervin
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Brittany C Wiseman
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.,Molecular and Cellular Biology, MacEwan University, Edmonton, AB, Canada.,SMALP Network, Edmonton, AB, Canada
| | - Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.,SMALP Network, Edmonton, AB, Canada
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8
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Kervin TA, Overduin M. Regulation of the Phosphoinositide Code by Phosphorylation of Membrane Readers. Cells 2021; 10:cells10051205. [PMID: 34069055 PMCID: PMC8156045 DOI: 10.3390/cells10051205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/07/2021] [Accepted: 05/09/2021] [Indexed: 02/07/2023] Open
Abstract
The genetic code that dictates how nucleic acids are translated into proteins is well known, however, the code through which proteins recognize membranes remains mysterious. In eukaryotes, this code is mediated by hundreds of membrane readers that recognize unique phosphatidylinositol phosphates (PIPs), which demark organelles to initiate localized trafficking and signaling events. The only superfamily which specifically detects all seven PIPs are the Phox homology (PX) domains. Here, we reveal that throughout evolution, these readers are universally regulated by the phosphorylation of their PIP binding surfaces based on our analysis of existing and modelled protein structures and phosphoproteomic databases. These PIP-stops control the selective targeting of proteins to organelles and are shown to be key determinants of high-fidelity PIP recognition. The protein kinases responsible include prominent cancer targets, underscoring the critical role of regulated membrane readership.
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9
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Marine alkaloid monanchoxymycalin C: a new specific activator of JNK1/2 kinase with anticancer properties. Sci Rep 2020; 10:13178. [PMID: 32764580 PMCID: PMC7411023 DOI: 10.1038/s41598-020-69751-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/16/2020] [Indexed: 12/22/2022] Open
Abstract
Monanchoxymycalin C (MomC) is a new marine pentacyclic guanidine alkaloid, recently isolated from marine sponge Monanchora pulchra by us. Here, anticancer activity and mechanism of action was investigated for the first time using a human prostate cancer (PCa) model. MomC was active in all PCa cell lines at low micromolar concentrations and induced an unusual caspase-independent, non-apoptotic cell death. Kinase activity screening identified activation of mitogen-activated protein kinase (MAPK) c-Jun N-terminal protein kinase (JNK1/2) to be one of the primary molecular mechanism of MomC anticancer activity. Functional assays demonstrated a specific and selective JNK1/2 activation prior to the induction of other cell death related processes. Inhibition of JNK1/2 by pretreatment with the JNK-inhibitor SP600125 antagonized cytotoxic activity of the marine compound. MomC caused an upregulation of cytotoxic ROS. However, in contrast to other ROS-inducing agents, co-treatment with PARP-inhibitor olaparib revealed antagonistic effects indicating an active PARP to be necessary for MomC activity. Interestingly, although no direct regulation of p38 and ERK1/2 were detected, active p38 kinase was required for MomC efficacy, while the inhibition of ERK1/2 increased its cytotoxicity. In conclusion, MomC shows promising activity against PCa, which is exerted via JNK1/2 activation and non-apoptotic cell death.
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10
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Mohammed S, Vineetha NS, James S, Aparna JS, Babu Lankadasari M, Maeda T, Ghosh A, Saha S, Li QZ, Spiegel S, Harikumar KB. Regulatory role of SphK1 in TLR7/9-dependent type I interferon response and autoimmunity. FASEB J 2020; 34:4329-4347. [PMID: 31971297 DOI: 10.1096/fj.201902847r] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 01/08/2020] [Accepted: 01/10/2020] [Indexed: 12/16/2022]
Abstract
Plasmacytoid dendritic cells (pDCs) express Toll like receptors (TLRs) that modulate the immune response by production of type I interferons. Here, we report that sphingosine kinase 1 (SphK1) which produces the bioactive sphingolipid metabolite, sphingosine 1-phosphate (S1P), plays a critical role in the pDC functions and interferon production. Although dispensable for the pDC development, SphK1 is essential for the pDC activation and production of type I IFN and pro-inflammatory cytokines stimulated by TLR7/9 ligands. SphK1 interacts with TLRs and specific inhibition or deletion of SphK1 in pDCs mitigates uptake of CpG oligonucleotide ligands by TLR9 ligand. In the pristane-induced murine lupus model, pharmacological inhibition of SphK1 or its genetic deletion markedly decreased the IFN signature, pDC activation, and glomerulonephritis. Moreover, increases in the SphK1 expression and S1P levels were observed in human lupus patients. Taken together, our results indicate a pivotal regulatory role for the SphK1/S1P axis in maintaining the balance between immunosurveillance and immunopathology and suggest that specific SphK1 inhibitors might be a new therapeutic avenue for the treatment of type I IFN-linked autoimmune disorders.
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Affiliation(s)
- Sabira Mohammed
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, India.,Manipal Academy of Higher Education (MAHE), Manipal, India
| | - Nalanda S Vineetha
- Department of Nephrology, Government Medical College, Thiruvananthapuram, India
| | - Shirley James
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, India
| | - Jayasekharan S Aparna
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, India
| | - Manendra Babu Lankadasari
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, India.,Manipal Academy of Higher Education (MAHE), Manipal, India
| | - Takahiro Maeda
- Department of Island and Community Medicine, Island Medical Research Institute, Nagasaki University Graduate School of Biomedical Science, Nagasaki, Japan
| | | | - Sudipto Saha
- Bioinformatics Center, Bose Institute, Kolkata, India
| | - Quan-Zhen Li
- Department of Immunology & Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA
| | - Kuzhuvelil B Harikumar
- Cancer Research Program, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, India
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11
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Tayebati SK. Phospholipid and Lipid Derivatives as Potential Neuroprotective Compounds. Molecules 2018; 23:molecules23092257. [PMID: 30189584 PMCID: PMC6225353 DOI: 10.3390/molecules23092257] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 08/22/2018] [Accepted: 09/04/2018] [Indexed: 12/13/2022] Open
Abstract
The worldwide demographical trend is changing towards a more elderly population. In particular, this phenomenon is increasing the number of neurodegenerative disease cases (e.g., Alzheimer’s disease) in advanced countries. Therefore, there is a fertile field for neuroprotective approaches to address this problem. A useful strategy to protect the membrane integrity of cells and reduce inflammatory processes. In this context, the neurons represent particularly vulnerable cells. Thus, a protection strategy should include their membrane preservation and improved anti-inflammatory processes. The contribution of phospholipid derivatives to this issue is crucial and many articles evidence their role in both health and disease. On the other hand, some lipids containing choline actively participate to increase the choline levels in the nervous system. It is acknowledged that the cholinergic system plays a pivotal role both in the central and in the peripheral nervous system. Neurons cannot synthesize choline, which is provided by the diet. The reuptake of ACh and its hydrolysis represent the principal source of choline. Therefore, to cover choline needs, choline-containing lipids may be used. There are different works which demonstrate their neuroprotective features This review article analyzes phospholipid and lipid derivatives that through different mechanisms are involved in these protective processes, although, sometimes the same molecules may behave as neurotoxic elements, therefore, their protective machinery should be detailed better.
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12
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Pulkoski-Gross MJ, Obeid LM. Molecular mechanisms of regulation of sphingosine kinase 1. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1413-1422. [PMID: 30591148 DOI: 10.1016/j.bbalip.2018.08.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 01/08/2023]
Abstract
Within the last 3 decades, there has been intense study of bioactive sphingolipids and the enzymes which metabolize those lipids. One enzyme is the critical lipid kinase sphingosine kinase 1 (SK1), which produces the potent and pleiotropic signaling lipid, sphingosine 1-phosphate (S1P). SK1 and S1P have been implicated in a host of different diseases including cancer, chronic inflammation, and metabolic diseases. However, while there is ample knowledge about the importance of these molecules in the development and progression of disease there is a dearth of knowledge of the molecular mechanisms which regulate SK1 function. In this review, we will cover some of the more recent and exciting findings about the different ways SK1 function can be regulated, from transcriptional regulation to protein stability. Finally, we will delve into recent structural insights into SK1 and how they might relate to function at cell membranes.
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Affiliation(s)
- Michael J Pulkoski-Gross
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11790, USA; Department of Medicine, The Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790, USA.
| | - Lina M Obeid
- Department of Medicine, The Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790, USA; Northport Veterans Affairs Medical Center, Northport, NY 11768, USA.
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13
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Moruno Manchon JF, Uzor NE, Finkbeiner S, Tsvetkov AS. SPHK1/sphingosine kinase 1-mediated autophagy differs between neurons and SH-SY5Y neuroblastoma cells. Autophagy 2018; 12:1418-24. [PMID: 27467777 DOI: 10.1080/15548627.2016.1183082] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Although implicated in neurodegeneration, autophagy has been characterized mostly in yeast and mammalian non-neuronal cells. In a recent study, we sought to determine if SPHK1 (sphingosine kinase 1), implicated previously in macroautophagy/autophagy in cancer cells, regulates autophagy in neurons. SPHK1 synthesizes sphingosine-1-phosphate (S1P), a bioactive lipid involved in cell survival. In our study, we discovered that, when neuronal autophagy is pharmacologically stimulated, SPHK1 relocalizes to the endocytic and autophagic organelles. Interestingly, in non-neuronal cells stimulated with growth factors, SPHK1 translocates to the plasma membrane, where it phosphorylates sphingosine to produce S1P. Whether SPHK1 also binds to the endocytic and autophagic organelles in non-neuronal cells upon induction of autophagy has not been demonstrated. Here, we determined if the effect in neurons is operant in the SH-SY5Y neuroblastoma cell line. In both non-differentiated and differentiated SH-SY5Y cells, a short incubation of cells in amino acid-free medium stimulated the formation of SPHK1-positive puncta, as in neurons. We also found that, unlike neurons in which these puncta represent endosomes, autophagosomes, and amphisomes, in SH-SY5Y cells SPHK1 is bound only to the endosomes. In addition, a dominant negative form of SPHK1 was very toxic to SH-SY5Y cells, but cultured primary cortical neurons tolerated it significantly better. These results suggest that autophagy in neurons is regulated by mechanisms that differ, at least in part, from those in SH-SY5Y cells.
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Affiliation(s)
- Jose Felix Moruno Manchon
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA
| | - Ndidi-Ese Uzor
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA.,b University of Texas Graduate School of Biomedical Sciences , Houston , TX , USA
| | - Steven Finkbeiner
- c Gladstone Institute of Neurological Disease and the Taube/Koret Center for Neurodegenerative Disease Research , San Francisco , CA , USA.,d Departments of Neurology and Physiology , University of California , San Francisco , CA , USA
| | - Andrey S Tsvetkov
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA.,b University of Texas Graduate School of Biomedical Sciences , Houston , TX , USA
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14
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The secret life of kinases: insights into non-catalytic signalling functions from pseudokinases. Biochem Soc Trans 2017; 45:665-681. [PMID: 28620028 DOI: 10.1042/bst20160331] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 12/31/2022]
Abstract
Over the past decade, our understanding of the mechanisms by which pseudokinases, which comprise ∼10% of the human and mouse kinomes, mediate signal transduction has advanced rapidly with increasing structural, biochemical, cellular and genetic studies. Pseudokinases are the catalytically defective counterparts of conventional, active protein kinases and have been attributed functions as protein interaction domains acting variously as allosteric modulators of conventional protein kinases and other enzymes, as regulators of protein trafficking or localisation, as hubs to nucleate assembly of signalling complexes, and as transmembrane effectors of such functions. Here, by categorising mammalian pseudokinases based on their known functions, we illustrate the mechanistic diversity among these proteins, which can be viewed as a window into understanding the non-catalytic functions that can be exerted by conventional protein kinases.
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15
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Lima S, Milstien S, Spiegel S. Sphingosine and Sphingosine Kinase 1 Involvement in Endocytic Membrane Trafficking. J Biol Chem 2017; 292:3074-3088. [PMID: 28049734 DOI: 10.1074/jbc.m116.762377] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/22/2016] [Indexed: 12/22/2022] Open
Abstract
The balance between cholesterol and sphingolipids within the plasma membrane has long been implicated in endocytic membrane trafficking. However, in contrast to cholesterol functions, little is still known about the roles of sphingolipids and their metabolites. Perturbing the cholesterol/sphingomyelin balance was shown to induce narrow tubular plasma membrane invaginations enriched with sphingosine kinase 1 (SphK1), the enzyme that converts the bioactive sphingolipid metabolite sphingosine to sphingosine-1-phosphate, and suggested a role for sphingosine phosphorylation in endocytic membrane trafficking. Here we show that sphingosine and sphingosine-like SphK1 inhibitors induced rapid and massive formation of vesicles in diverse cell types that accumulated as dilated late endosomes. However, much smaller vesicles were formed in SphK1-deficient cells. Moreover, inhibition or deletion of SphK1 prolonged the lifetime of sphingosine-induced vesicles. Perturbing the plasma membrane cholesterol/sphingomyelin balance abrogated vesicle formation. This massive endosomal influx was accompanied by dramatic recruitment of the intracellular SphK1 and Bin/Amphiphysin/Rvs domain-containing proteins endophilin-A2 and endophilin-B1 to enlarged endosomes and formation of highly dynamic filamentous networks containing endophilin-B1 and SphK1. Together, our results highlight the importance of sphingosine and its conversion to sphingosine-1-phosphate by SphK1 in endocytic membrane trafficking.
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Affiliation(s)
- Santiago Lima
- Department of Biochemistry and Molecular Biology and Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298.
| | - Sheldon Milstien
- Department of Biochemistry and Molecular Biology and Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology and Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298.
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16
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Charng WL, Karaca E, Coban Akdemir Z, Gambin T, Atik MM, Gu S, Posey JE, Jhangiani SN, Muzny DM, Doddapaneni H, Hu J, Boerwinkle E, Gibbs RA, Rosenfeld JA, Cui H, Xia F, Manickam K, Yang Y, Faqeih EA, Al Asmari A, Saleh MAM, El-Hattab AW, Lupski JR. Exome sequencing in mostly consanguineous Arab families with neurologic disease provides a high potential molecular diagnosis rate. BMC Med Genomics 2016; 9:42. [PMID: 27435318 PMCID: PMC4950750 DOI: 10.1186/s12920-016-0208-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 07/08/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neurodevelopment is orchestrated by a wide range of genes, and the genetic causes of neurodevelopmental disorders are thus heterogeneous. We applied whole exome sequencing (WES) for molecular diagnosis and in silico analysis to identify novel disease gene candidates in a cohort from Saudi Arabia with primarily Mendelian neurologic diseases. METHODS We performed WES in 31 mostly consanguineous Arab families and analyzed both single nucleotide and copy number variants (CNVs) from WES data. Interaction/expression network and pathway analyses, as well as paralog studies were utilized to investigate potential pathogenicity and disease association of novel candidate genes. Additional cases for candidate genes were identified through the clinical WES database at Baylor Miraca Genetics Laboratories and GeneMatcher. RESULTS We found known pathogenic or novel variants in known disease genes with phenotypic expansion in 6 families, disease-associated CNVs in 2 families, and 12 novel disease gene candidates in 11 families, including KIF5B, GRM7, FOXP4, MLLT1, and KDM2B. Overall, a potential molecular diagnosis was provided by variants in known disease genes in 17 families (54.8 %) and by novel candidate disease genes in an additional 11 families, making the potential molecular diagnostic rate ~90 %. CONCLUSIONS Molecular diagnostic rate from WES is improved by exome-predicted CNVs. Novel candidate disease gene discovery is facilitated by paralog studies and through the use of informatics tools and available databases to identify additional evidence for pathogenicity. TRIAL REGISTRATION Not applicable.
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Affiliation(s)
- Wu-Lin Charng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA
| | - Ender Karaca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA
| | - Zeynep Coban Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA
| | - Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA
| | - Mehmed M Atik
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA
| | - Shen Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA
| | - Shalini N Jhangiani
- The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Donna M Muzny
- The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Harsha Doddapaneni
- The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jianhong Hu
- The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Eric Boerwinkle
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.,Human Genetics Center, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Richard A Gibbs
- The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,Exome Laboratory, Baylor Miraca Genetics Laboratories, Houston, TX, 77030, USA
| | - Hong Cui
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,Exome Laboratory, Baylor Miraca Genetics Laboratories, Houston, TX, 77030, USA
| | - Fan Xia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,Exome Laboratory, Baylor Miraca Genetics Laboratories, Houston, TX, 77030, USA
| | - Kandamurugu Manickam
- Division of Molecular and Human Genetics, Nationwide Children's Hospital, Columbus, OH, 43205, USA
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,Exome Laboratory, Baylor Miraca Genetics Laboratories, Houston, TX, 77030, USA
| | - Eissa A Faqeih
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia
| | - Ali Al Asmari
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia
| | - Mohammed A M Saleh
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia
| | - Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Department of Pediatrics, Tawam Hospital, Al-Ain, United Arab Emirates
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA. .,The Baylor-Hopkins Center for Mendelian Genomics, Houston, TX, 77030, USA. .,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Pediatrics, Texas Children's Hospital, Houston, TX, 77030, USA.
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17
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Yagoub D, Wilkins MR, Lay AJ, Kaczorowski DC, Hatoum D, Bajan S, Hutvagner G, Lai JH, Wu W, Martiniello-Wilks R, Xia P, McGowan EM. Sphingosine kinase 1 isoform-specific interactions in breast cancer. Mol Endocrinol 2014; 28:1899-915. [PMID: 25216046 DOI: 10.1210/me.2013-1423] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Sphingosine kinase 1 (SK1) is a signaling enzyme that catalyzes the formation of sphingosine-1-phosphate. Overexpression of SK1 is causally associated with breast cancer progression and resistance to therapy. SK1 inhibitors are currently being investigated as promising breast cancer therapies. Two major transcriptional isoforms, SK143 kDa and SK151 kDa, have been identified; however, the 51 kDa variant is predominant in breast cancer cells. No studies have investigated the protein-protein interactions of the 51 kDa isoform and whether the two SK1 isoforms differ significantly in their interactions. Seeking an understanding of the regulation and role of SK1, we used a triple-labeling stable isotope labeling by amino acids in cell culture-based approach to identify SK1-interacting proteins common and unique to both isoforms. Of approximately 850 quantified proteins in SK1 immunoprecipitates, a high-confidence list of 30 protein interactions with each SK1 isoform was generated via a meta-analysis of multiple experimental replicates. Many of the novel identified SK1 interaction partners such as supervillin, drebrin, and the myristoylated alanine-rich C-kinase substrate-related protein supported and highlighted previously implicated roles of SK1 in breast cancer cell migration, adhesion, and cytoskeletal remodeling. Of these interactions, several were found to be exclusive to the 43 kDa isoform of SK1, including the protein phosphatase 2A, a previously identified SK1-interacting protein. Other proteins such as allograft inflammatory factor 1-like protein, the latent-transforming growth factor β-binding protein, and dipeptidyl peptidase 2 were found to associate exclusively with the 51 kDa isoform of SK1. In this report, we have identified common and isoform-specific SK1-interacting partners that provide insight into the molecular mechanisms that drive SK1-mediated oncogenicity.
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Affiliation(s)
- Daniel Yagoub
- School of Biotechnology and Biomolecular Sciences (D.Y., M.R.W.), University of New South Wales, Sydney 2052, Australia; Centenary Institute (D.Y., A.L., D.G.K., P.X., E.M.M.), Sydney 2042, Australia; Translational Cancer Research Group (D.H., R.M.-W., E.M.M.), Faculty of Science, School of Medical and Molecular Biosciences, and Faculty of Engineering and Information Technology (S.B., G.H.), University of Technology Sydney, Sydney, New South Wales 2007, Australia; Department of Biochemistry (J.H.L., W.W.), Tufts University School of Medicine, Boston, Massachusetts 02111; Shanghai Medical School (P.X.), Fudan University, 200433 Shanghai, People's Republic of China; and Sydney Medical School (E.M.M.), The University of Sydney, Sydney 2006, Australia
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18
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Shen H, Giordano F, Wu Y, Chan J, Zhu C, Milosevic I, Wu X, Yao K, Chen B, Baumgart T, Sieburth D, De Camilli P. Coupling between endocytosis and sphingosine kinase 1 recruitment. Nat Cell Biol 2014; 16:652-62. [PMID: 24929359 PMCID: PMC4230894 DOI: 10.1038/ncb2987] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 05/09/2014] [Indexed: 12/13/2022]
Abstract
Genetic studies have suggested a functional link between cholesterol/sphingolipid metabolism and endocytic membrane traffic. Here we show that perturbing the cholesterol/sphingomyelin balance in the plasma membrane results in the massive formation of clusters of narrow endocytic tubular invaginations positive for N-BAR proteins. These tubules are intensely positive for sphingosine kinase 1 (SPHK1). SPHK1 is also targeted to physiologically occurring early endocytic intermediates, and is highly enriched in nerve terminals, which are cellular compartments specialized for exo/endocytosis. Membrane recruitment of SPHK1 involves a direct, curvature-sensitive interaction with the lipid bilayer mediated by a hydrophobic patch on the enzyme's surface. The knockdown of SPHKs results in endocytic recycling defects, and a mutation that disrupts the hydrophobic patch of Caenorhabditis elegans SPHK fails to rescue the neurotransmission defects in loss-of-function mutants of this enzyme. Our studies support a role for sphingosine phosphorylation in endocytic membrane trafficking beyond the established function of sphingosine-1-phosphate in intercellular signalling.
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Affiliation(s)
- Hongying Shen
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA [3]
| | - Francesca Giordano
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA [3]
| | - Yumei Wu
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Jason Chan
- 1] Zilkha Neurogenetic Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA [2]
| | - Chen Zhu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ira Milosevic
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Xudong Wu
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Kai Yao
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Bo Chen
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Tobias Baumgart
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Derek Sieburth
- Zilkha Neurogenetic Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Pietro De Camilli
- 1] Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA [2] Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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19
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Alshaker H, Sauer L, Monteil D, Ottaviani S, Srivats S, Böhler T, Pchejetski D. Therapeutic potential of targeting SK1 in human cancers. Adv Cancer Res 2013; 117:143-200. [PMID: 23290780 DOI: 10.1016/b978-0-12-394274-6.00006-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Sphingosine kinase 1 (SK1) is a lipid enzyme with oncogenic properties that converts the proapoptotic lipids ceramide and sphingosine into the antiapoptotic lipid sphingosine-1-phosphate and activates the signal transduction pathways that lead to cell proliferation, migration, the activation of the inflammatory response, and the impairment of apoptosis. There is compelling evidence that SK1 activation contributes to cancer progression leading to increased oncogenic transformation, tumor growth, resistance to therapies, tumor neovascularization, and metastatic spread. High levels of SK1 expression or activity have been associated with a poor prognosis in several human cancers. Recent studies using cancer cell and mouse models demonstrate a significant potential for SK1-targeting therapies to synergize with the effects of chemotherapy and radiotherapy; however, until recently the absence of clinically applicable SK1 inhibitors has limited the translation of these findings into patients. With the recent discovery of SK1 inhibiting properties of a clinically approved drug FTY720 (Fingolimod), SK1 has gained significant attention from both clinicians and the pharmaceutical industry and it is hoped that trials of newly developed SK1 inhibitors may follow soon. This review provides an overview of the SK1 signaling, its relevance to cancer progression, and the potential clinical significance of targeting SK1 for improved local or systemic control of human cancers.
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Affiliation(s)
- Heba Alshaker
- Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
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20
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Post-translational regulation of sphingosine kinases. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:147-56. [DOI: 10.1016/j.bbalip.2012.07.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 07/04/2012] [Accepted: 07/06/2012] [Indexed: 12/22/2022]
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21
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Liang H, Cheung LWT, Li J, Ju Z, Yu S, Stemke-Hale K, Dogruluk T, Lu Y, Liu X, Gu C, Guo W, Scherer SE, Carter H, Westin SN, Dyer MD, Verhaak RGW, Zhang F, Karchin R, Liu CG, Lu KH, Broaddus RR, Scott KL, Hennessy BT, Mills GB. Whole-exome sequencing combined with functional genomics reveals novel candidate driver cancer genes in endometrial cancer. Genome Res 2012; 22:2120-9. [PMID: 23028188 PMCID: PMC3483541 DOI: 10.1101/gr.137596.112] [Citation(s) in RCA: 189] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Endometrial cancer is the most common gynecological malignancy, with more than 280,000 cases occurring annually worldwide. Although previous studies have identified important common somatic mutations in endometrial cancer, they have primarily focused on a small set of known cancer genes and have thus provided a limited view of the molecular basis underlying this disease. Here we have developed an integrated systems-biology approach to identifying novel cancer genes contributing to endometrial tumorigenesis. We first performed whole-exome sequencing on 13 endometrial cancers and matched normal samples, systematically identifying somatic alterations with high precision and sensitivity. We then combined bioinformatics prioritization with high-throughput screening (including both shRNA-mediated knockdown and expression of wild-type and mutant constructs) in a highly sensitive cell viability assay. Our results revealed 12 potential driver cancer genes including 10 tumor-suppressor candidates (ARID1A, INHBA, KMO, TTLL5, GRM8, IGFBP3, AKTIP, PHKA2, TRPS1, and WNT11) and two oncogene candidates (ERBB3 and RPS6KC1). The results in the “sensor” cell line were recapitulated by siRNA-mediated knockdown in endometrial cancer cell lines. Focusing on ARID1A, we integrated mutation profiles with functional proteomics in 222 endometrial cancer samples, demonstrating that ARID1A mutations frequently co-occur with mutations in the phosphatidylinositol 3-kinase (PI3K) pathway and are associated with PI3K pathway activation. siRNA knockdown in endometrial cancer cell lines increased AKT phosphorylation supporting ARID1A as a novel regulator of PI3K pathway activity. Our study presents the first unbiased view of somatic coding mutations in endometrial cancer and provides functional evidence for diverse driver genes and mutations in this disease.
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Affiliation(s)
- Han Liang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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22
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Karliner JS. Sphingosine kinase and sphingosine 1-phosphate in the heart: a decade of progress. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:203-12. [PMID: 22735359 DOI: 10.1016/j.bbalip.2012.06.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/14/2012] [Accepted: 06/17/2012] [Indexed: 12/11/2022]
Abstract
Activation of sphingosine kinase/sphingosine 1-phosphate (SK/S1P)-mediated signaling has emerged as a critical cardioprotective pathway in response to acute ischemia/reperfusion injury. S1P is released in both ischemic pre- and post-conditioning. Application of exogenous S1P to cultured cardiac myocytes subjected to hypoxia or treatment of isolated hearts either before ischemia or at the onset of reperfusion exerts prosurvival effects. Synthetic congeners of S1P such as FTY720 mimic these responses. Gene targeted mice null for the SK1 isoform whose hearts are subjected to ischemia/reperfusion injury exhibit increased infarct size and respond poorly either to ischemic pre- or postconditioning. Measurements of cardiac SK activity and S1P parallel these observations. Experiments in SK2 knockout mice have revealed that this isoform is necessary for survival in the heart. High density lipoprotein (HDL) is a major carrier of S1P, and studies of hearts in which selected S1P receptors have been inhibited implicate the S1P cargo of HDL in cardioprotection. Inhibition of S1P lyase, an endogenous enzyme that degrades S1P, also leads to cardioprotection. These observations have considerable relevance for future therapeutic approaches to acute and chronic myocardial injury. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.
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Abstract
Sphingosine kinase 1 (SK1) is a lipid enzyme with oncogenic properties that converts the proapoptotic lipid sphingosine into the antiapoptotic lipid sphingosine-1-phosphate, which activates the signal transduction pathways that lead to cell proliferation, migration, activation of the inflammatory response and impairment of apoptosis. Compelling evidence suggests that SK1 activation contributes to cancer progression leading to increased oncogenic transformation, tumor growth, resistance to therapies, tumor neovascularization and metastatic spread. High levels of SK1 expression or activity have been associated with poor prognosis in several cancers, including those of the prostate. Recent studies using prostate cancer cell and mouse models demonstrate a significant potential for SK1-targeting therapies to synergize with the effects of docetaxel chemotherapy and radiotherapy. However, until recently the absence of clinically applicable SK1 inhibitors has limited the translation of these findings into patients. With the recent discovery that clinically approved drug fingolimod has SK1-inhibiting properties, SK1 has gained significant attention from both clinicians and the pharmaceutical industry and it is hoped that trials of newly developed SK1 inhibitors might follow soon.
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24
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Pasikowski P, Cydzik M, Kluczyk A, Stefanowicz P, Szewczuk Z. Ubiquitin fragments: their known biological activities and putative roles. Biomol Concepts 2010; 1:67-83. [PMID: 25961987 DOI: 10.1515/bmc.2010.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Ubiquitin (Ub) is involved in many key processes of cell biology. Identification of compounds that could interfere in the ubiquitination process is of importance. It could be expected that peptides derived from the Ub-binding regions might be able to interact with Ub receptors themselves and modify an ability of the Ub receptors interactions. This review summarizes current knowledge about known Ub-derived peptides and discusses putative activity of unexplored Ub fragments. Among identified biologically active Ub-derived peptides, its decapeptide fragment of the LEDGRTLSDY sequence was found to exhibit strong immunosuppressive effects on the cellular and humoral immune responses, comparable to that of cyclosporine. Some of the Ub fragments possess strong antibacterial and antifungal potency. In the search for new peptides that could interfere in the interaction of Ub with other proteins, we investigated the pentapeptide Ub sequences present in non-ubiquitin proteins. Based on examination of the Swiss-Prot database, we postulated that sequences of some Ub fragments often exist in other protein molecules. However, some of those motives are represented more frequently than others and could be involved in regulation of cellular processes related to Ub.
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25
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Characterization of PXK as a protein involved in epidermal growth factor receptor trafficking. Mol Cell Biol 2010; 30:1689-702. [PMID: 20086096 DOI: 10.1128/mcb.01105-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The phox homology (PX) domain is a phosphoinositide-binding module that typically binds phosphatidylinositol 3-phosphate. Out of 47 mammalian proteins containing PX domains, more than 30 are denoted sorting nexins and several of these have been implicated in internalization of cell surface proteins to the endosome, where phosphatidylinositol-3-phosphate is concentrated. Here we investigated a multimodular protein termed PXK, composed of a PX domain, a protein kinase-like domain, and a WASP homology 2 domain. We show that the PX domain of PXK localizes this protein to the endosomal membrane via binding to phosphatidylinositol 3-phosphate. PXK expression in COS7 cells accelerated the ligand-induced internalization and degradation of epidermal growth factor receptors by a mechanism requiring phosphatidylinositol 3-phosphate binding but not involving the WASP homology 2 domain. Conversely, depletion of PXK using RNA interference decreased the rate of epidermal growth factor receptor internalization and degradation. Ubiquitination of epidermal growth factor receptor by the ligand stimulation was enhanced in PXK-expressing cells. These results indicate that PXK plays a critical role in epidermal growth factor receptor trafficking through modulating ligand-induced ubiquitination of the receptor.
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Extracellular and Intracellular Actions of Sphingosine-1-Phosphate. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 688:141-55. [DOI: 10.1007/978-1-4419-6741-1_10] [Citation(s) in RCA: 262] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Deshmukh K, Anamika K, Srinivasan N. Evolution of domain combinations in protein kinases and its implications for functional diversity. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2009; 102:1-15. [PMID: 20026163 DOI: 10.1016/j.pbiomolbio.2009.12.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 12/10/2009] [Indexed: 01/01/2023]
Abstract
Protein kinases phosphorylating Ser/Thr/Tyr residues in several cellular proteins exert tight control over their biological functions. They constitute the largest protein family in most eukaryotic species. Protein kinases classified based on sequence similarity in their catalytic domains, cluster into subfamilies, which share gross functional properties. Many protein kinases are associated or tethered covalently to domains that serve as adapter or regulatory modules, aiding substrate recruitment, specificity, and also serve as scaffolds. Hence the modular organisation of the protein kinases serves as guidelines to their functional and molecular properties. Analysis of genomic repertoires of protein kinases in eukaryotes have revealed wide spectrum of domain organisation across various subfamilies of kinases. Occurrence of organism-specific novel domain combinations suggests functional diversity achieved by protein kinases in order to regulate variety of biological processes. In addition, domain architecture of protein kinases revealed existence of hybrid protein kinase subfamilies and their emerging roles in the signaling of eukaryotic organisms. In this review we discuss the repertoire of non-kinase domains tethered to multi-domain kinases in the metazoans. Similarities and differences in the domain architectures of protein kinases in these organisms indicate conserved and unique features that are critical to functional specialization.
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Affiliation(s)
- Krupa Deshmukh
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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Abstract
Activation of sphingosine kinase/sphingosine 1-phosphate-mediated signaling has emerged as a critical cardioprotective pathway in response to acute ischemia/reperfusion injury. Application of exogenous sphingosine 1-phosphate (S1P) in cultured cardiac myocytes subjected to hypoxia or treatment of isolated hearts either before ischemia or at the onset of reperfusion (pharmacologic preconditioning or postconditioning) exerts prosurvival effects. Synthetic congeners of S1P mimic these responses. Gene-targeted mice null for the sphingosine kinase 1 isoform whose hearts are subjected to ischemia/reperfusion injury exhibit increased infarct size and respond poorly either to ischemic preconditioning or to ischemic postconditioning. Measurements of cardiac sphingosine kinase activity and S1P parallel these observations. High-density lipoprotein is a major carrier of S1P, and studies of hearts in which selected S1P receptors have been deleted implicate the S1P cargo of high-density lipoprotein in cardioprotection. These observations have considerable relevance for future therapeutic approaches to acute and chronic myocardial injury.
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Abstract
Activation of sphingosine kinase/sphingosine-1-phosphate (SK/S1P)-mediated signalling has been recognized as critical for cardioprotection in response to acute ischaemia/reperfusion injury. Incubation of S1P with cultured cardiac myocytes subjected to hypoxia or treatment of isolated hearts either before ischaemia or at the onset of reperfusion (pharmacologic pre- or postconditioning) results in reduced myocyte injury. Synthetic agonists active at S1P receptors mimic these responses. Gene-targeted mice null for the SK1 isoform whose hearts are subjected to ischaemia/reperfusion injury exhibit increased infarct size and respond poorly either to ischaemic pre- or postconditioning. Measurements of cardiac SK activity and S1P parallel these observations. Ischaemic postconditioning combined with sphingosine and S1P rescues the heart from prolonged ischaemia. These observations may have considerable relevance for future therapeutic approaches to acute and chronic myocardial injury.
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Affiliation(s)
- Joel S Karliner
- Cardiology Section (111C), VA Medical Center, San Francisco, University of California, 4150 Clement Street, San Francisco, CA 94121, USA.
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Okada T, Kajimoto T, Jahangeer S, Nakamura SI. Sphingosine kinase/sphingosine 1-phosphate signalling in central nervous system. Cell Signal 2008; 21:7-13. [PMID: 18694820 DOI: 10.1016/j.cellsig.2008.07.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 07/04/2008] [Accepted: 07/17/2008] [Indexed: 11/30/2022]
Abstract
Sphingolipids were once regarded as inert structural components of cell membranes. Now these metabolites are generally believed to be important bioactive molecules that control a wide repertoire of cellular processes such as proliferation and survival of cells. Along with these ubiquitous cell functions observed in many peripheral tissues sphingolipid metabolites, especially sphingosine 1-phosphate, exert important neuron-specific functions such as regulation of neurotransmitter release. This review summarizes physiological and pathological roles of sphingolipid metabolites emphasizing the role of sphingosine 1-phosphate in the central nervous system.
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Affiliation(s)
- Taro Okada
- Division of Biochemistry, Department of Biochemistry/Molecular Biology, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
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Filamin A links sphingosine kinase 1 and sphingosine-1-phosphate receptor 1 at lamellipodia to orchestrate cell migration. Mol Cell Biol 2008; 28:5687-97. [PMID: 18644866 DOI: 10.1128/mcb.00465-08] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Sphingosine kinase 1 (SphK1) catalyzes the phosphorylation of sphingosine to produce the potent lipid mediator sphingosine-1-phosphate (S1P), which plays a critical role in cell motility via its cell surface receptors. Here, we have identified filamin A (FLNa), an actin-cross-linking protein involved in cell movement, as a bona fide SphK1-interacting protein. Heregulin stimulated SphK1 activity only in FLNa-expressing A7 melanoma cells but not in FLNa-deficient cells and induced its translocation and colocalization with FLNa at lamellipodia. SphK1 was required for heregulin-induced migration, lamellipodia formation, activation of PAK1, and subsequent FLNa phosphorylation. S1P directly stimulated PAK1 kinase, suggesting that it may be a target of intracellularly generated S1P. Heregulin also induced colocalization of S1P(1) (promotility S1P receptor) but not S1P(2), with SphK1 and FLNa at membrane ruffles. Moreover, an S1P(1) antagonist inhibited the lamellipodia formation induced by heregulin. Hence, FLNa links SphK1 and S1P(1) to locally influence the dynamics of actin cytoskeletal structures by orchestrating the concerted actions of the triumvirate of SphK1, FLNa, and PAK1, each of which requires and/or regulates the actions of the others, at lamellipodia to promote cell movement.
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Leclercq TM, Moretti PAB, Vadas MA, Pitson SM. Eukaryotic elongation factor 1A interacts with sphingosine kinase and directly enhances its catalytic activity. J Biol Chem 2008; 283:9606-14. [PMID: 18263879 PMCID: PMC2442288 DOI: 10.1074/jbc.m708782200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 01/23/2008] [Indexed: 01/07/2023] Open
Abstract
Sphingosine 1-phosphate (S1P) has many important roles in mammalian cells, including contributing to the control of cell survival and proliferation. S1P is generated by sphingosine kinases (SKs), of which two mammalian isoforms have been identified (SK1 and SK2). To gain a better understanding of SK regulation, we have used a yeast two-hybrid screen to identify SK1-interacting proteins and established elongation factor 1A (eEF1A) as one such protein that associates with both SK1 and SK2. We show the direct interaction of eEF1A with the SKs in vitro, whereas the physiological relevance of this association was demonstrated by co-immunoprecipitation of the endogenous proteins from cell lysates. Although the canonical role of eEF1A resides in protein synthesis, it has also been implicated in other roles, including regulating the activity of some signaling enzymes. Thus, we examined the potential role of eEF1A in regulation of the SKs and show that eEF1A is able to directly increase the activity of SK1 and SK2 approximately 3-fold in vitro. Substrate kinetics demonstrated that eEF1A increased the catalytic rate of both SKs, while having no observable effect on substrate affinities of these enzymes for either ATP or sphingosine. Overexpression of eEF1A in quiescent Chinese hamster ovary cells increased cellular SK activity, whereas a small interfering RNA-mediated decrease in eEF1A levels in MCF7 cells substantially reduced cellular SK activity and S1P levels, supporting the in vivo physiological relevance of this interaction. Thus, this study has established a novel mechanism of regulation of both SK1 and SK2 that is mediated by their interaction with eEF1A.
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Affiliation(s)
- Tamara M Leclercq
- Hanson Institute, Division of Human Immunology, Institute of Medical and Veterinary Science, Frome Road, Adelaide, South Australia 5000, Australia
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34
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Capra M, Nuciforo PG, Confalonieri S, Quarto M, Bianchi M, Nebuloni M, Boldorini R, Pallotti F, Viale G, Gishizky ML, Draetta GF, Di Fiore PP. Frequent alterations in the expression of serine/threonine kinases in human cancers. Cancer Res 2007; 66:8147-54. [PMID: 16912193 DOI: 10.1158/0008-5472.can-05-3489] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Protein kinases constitute a large family of regulatory enzymes involved in the homeostasis of virtually every cellular process. Subversion of protein kinases has been frequently implicated in malignant transformation. Within the family, serine/threonine kinases (STK) have received comparatively lesser attention, vis-a-vis tyrosine kinases, in terms of their involvement in human cancers. Here, we report a large-scale screening of 125 STK, selected to represent all major subgroups within the subfamily, on nine different types of tumors ( approximately 200 patients), by using in situ hybridization on tissue microarrays. Twenty-one STK displayed altered levels of transcripts in tumors, frequently with a clear tumor type-specific dimension. We identified three patterns of alterations in tumors: (a) overexpression in the absence of expression in the normal tissues (10 kinases), (b) overexpression in the presence of expression by normal tissues (8 kinases), and (c) underexpression (3 kinases). Selected members of the three classes were subjected to in-depth analysis on larger case collections and showed significant correlations between their altered expression and biological and/or clinical variables. Our findings suggest that alteration in the expression of STK is a relatively frequent occurrence in human tumors. Among the overexpressed kinases, 10 were undetectable in normal controls and are therefore ideal candidates for further validation as potential targets of molecular cancer therapy.
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Affiliation(s)
- Maria Capra
- Istituto FIRC di Oncologia Molecolare, Milan, Italy
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35
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Ding G, Sonoda H, Yu H, Kajimoto T, Goparaju SK, Jahangeer S, Okada T, Nakamura SI. Protein kinase D-mediated phosphorylation and nuclear export of sphingosine kinase 2. J Biol Chem 2007; 282:27493-27502. [PMID: 17635916 DOI: 10.1074/jbc.m701641200] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Sphingosine kinase (SPHK) is a key enzyme producing important messenger sphingosine 1-phosphate and is implicated in cell proliferation and suppression of apoptosis. Because the extent of agonist-induced activation of SPHK is modest, signaling via SPHK may be regulated through its localization at specific intracellular sites. Although the SPHK1 isoform has been extensively studied and characterized, the regulation of expression and function of the other isoform, SPHK2, remain largely unexplored. Here we describe an important post-translational modification, namely, phosphorylation of SPHK2 catalyzed by protein kinase D (PKD), which regulates its localization. Upon stimulation of HeLa cells by tumor promoter phorbol 12-myristate 13-acetate, a serine residue in a novel and putative nuclear export signal, identified for the first time, in SPHK2 was phosphorylated followed by SPHK2 export from the nucleus. Constitutively active PKD phosphorylated this serine residue in the nuclear export signal both in vivo and in vitro. Moreover, down-regulation of PKDs through RNA interference resulted in the attenuation of both basal and phorbol 12-myristate 13-acetate-induced phosphorylation, which was followed by the accumulation of SPHK2 in the nucleus in a manner rescued by PKD over-expression. These results indicate that PKD is a physiologically relevant enzyme for SPHK2 phosphorylation, which leads to its nuclear export for subsequent cellular signaling.
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Affiliation(s)
- Guo Ding
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-1, Chuo-ku, Kobe 650-0017, Japan
| | - Hirofumi Sonoda
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-1, Chuo-ku, Kobe 650-0017, Japan
| | - Huan Yu
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-1, Chuo-ku, Kobe 650-0017, Japan
| | - Taketoshi Kajimoto
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-1, Chuo-ku, Kobe 650-0017, Japan
| | - Sravan K Goparaju
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-1, Chuo-ku, Kobe 650-0017, Japan
| | - Saleem Jahangeer
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-1, Chuo-ku, Kobe 650-0017, Japan
| | - Taro Okada
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-1, Chuo-ku, Kobe 650-0017, Japan
| | - Shun-Ichi Nakamura
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-1, Chuo-ku, Kobe 650-0017, Japan.
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36
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Kihara A, Mitsutake S, Mizutani Y, Igarashi Y. Metabolism and biological functions of two phosphorylated sphingolipids, sphingosine 1-phosphate and ceramide 1-phosphate. Prog Lipid Res 2007; 46:126-44. [PMID: 17449104 DOI: 10.1016/j.plipres.2007.03.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Sphingolipids are major lipid constituents of the eukaryotic plasma membrane. Without certain sphingolipids, cells and/or embryos cannot survive, indicating that sphingolipids possess important physiological functions that are not substituted for by other lipids. One such role may be signaling. Recent studies have revealed that some sphingolipid metabolites, such as long-chain bases (LCBs; sphingosine (Sph) in mammals), long-chain base 1-phosphates (LCBPs; sphingosine 1-phosphate (S1P) in mammals), ceramide (Cer), and ceramide 1-phosphate (C1P), act as signaling molecules. The addition of phosphate groups to LCB/Sph and Cer generates LCBP/S1P and C1P, respectively. These phospholipids exhibit completely different functions than those of their precursors. In this review, we describe recent advances in understanding the functions of LCBP/S1P and C1P in mammals and in the yeast Saccharomyces cerevisiae. Since LCB/Sph, LCBP/S1P, Cer, and C1P are mutually convertible, regulation of not only the total amount of the each lipid but also of the overall balance in cellular levels is important. Therefore, we describe in detail their metabolic pathways, as well as the genes involved in each reaction.
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Affiliation(s)
- Akio Kihara
- Laboratory of Biomembrane and Biofunctional Chemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Nishi 6-Choume, Sapporo, Japan.
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Duan HF, Qu CK, Zhang QW, Yu WM, Wang H, Wu CT, Wang LS. Shp-2 tyrosine phosphatase is required for hepatocyte growth factor-induced activation of sphingosine kinase and migration in embryonic fibroblasts. Cell Signal 2006; 18:2049-55. [PMID: 16765027 DOI: 10.1016/j.cellsig.2006.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 04/08/2006] [Accepted: 04/19/2006] [Indexed: 10/24/2022]
Abstract
Shp-2, a ubiquitously expressed protein tyrosine phosphatase containing two Src homology 2 domains, plays an important role in integrating signaling from the cell surface receptors to intracellular signaling mechanisms. Previous studies have demonstrated that the Shp-2 is involved in hepatocyte growth factor (HGF)-induced cell scattering. Here we report that Shp-2 is required for the HGF-induced activation of sphingosine kinase-1 (SPK1), a highly conserved lipid kinase that plays an important role in cell migration. Loss-of-function mutation of Shp-2 did not affect the expression of SPK1, but resulted in its inactivation and the blockage of HGF-induced migration in embryonic fibroblasts. Reintroduction of functional wild type (WT) Shp-2 into the mutant cells partially restored SPK1 activation, and overexpression of SPK1 in these mutant cells enhanced HGF-induced cell migration. Inhibition of expression or activity of SPK1 in WT cells markedly decreased intracellular S1P levels and HGF-induced cell migration. Furthermore, we found that Shp-2 co-immunoprecipitated with SPK1 and c-Met in embryonic fibroblasts. These studies suggest that Shp-2 is an SPK1-interacting protein and that it plays an indispensable role in HGF-induced SPK1 activation.
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Affiliation(s)
- Hai-Feng Duan
- Department of Experimental Hematology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, P.R. China
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39
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Hait NC, Oskeritzian CA, Paugh SW, Milstien S, Spiegel S. Sphingosine kinases, sphingosine 1-phosphate, apoptosis and diseases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:2016-26. [PMID: 16996023 DOI: 10.1016/j.bbamem.2006.08.007] [Citation(s) in RCA: 367] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 08/15/2006] [Accepted: 08/16/2006] [Indexed: 12/31/2022]
Abstract
Sphingolipids are ubiquitous components of cell membranes and their metabolites ceramide (Cer), sphingosine (Sph), and sphingosine-1-phosphate (S1P) have important physiological functions, including regulation of cell growth and survival. Cer and Sph are associated with growth arrest and apoptosis. Many stress stimuli increase levels of Cer and Sph, whereas suppression of apoptosis is associated with increased intracellular levels of S1P. In addition, extracellular/secreted S1P regulates cellular processes by binding to five specific G protein coupled-receptors (GPCRs). S1P is generated by phosphorylation of Sph catalyzed by two isoforms of sphingosine kinases (SphK), type 1 and type 2, which are critical regulators of the "sphingolipid rheostat", producing pro-survival S1P and decreasing levels of pro-apoptotic Sph. Since sphingolipid metabolism is often dysregulated in many diseases, targeting SphKs is potentially clinically relevant. Here we review the growing recent literature on the regulation and the roles of SphKs and S1P in apoptosis and diseases.
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Affiliation(s)
- Nitai C Hait
- Department of Biochemistry, Virginia Commonwealth University School of Medicine, 1101 E. Marshall St., Richmond, VA 23298-0614, USA
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Mannan AU, Krawen P, Sauter SM, Boehm J, Chronowska A, Paulus W, Neesen J, Engel W. ZFYVE27 (SPG33), a novel spastin-binding protein, is mutated in hereditary spastic paraplegia. Am J Hum Genet 2006; 79:351-7. [PMID: 16826525 PMCID: PMC1559503 DOI: 10.1086/504927] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Accepted: 04/05/2006] [Indexed: 01/14/2023] Open
Abstract
Spastin, the most commonly mutated protein in the autosomal dominant form of hereditary spastic paraplegia (AD-HSP) has been suggested to be involved in vesicular cargo trafficking; however, a comprehensive function of spastin has not yet been elucidated. To characterize the molecular function of spastin, we used the yeast two-hybrid approach to identify new interacting partners of spastin. Here, we report ZFYVE27, a novel member of the FYVE-finger family of proteins, as a specific spastin-binding protein, and we validate the interaction by both in vivo coimmunoprecipitation and colocalization experiments in mammalian cells. More importantly, we report a German family with AD-HSP in which ZFYVE27 (SPG33) is mutated; furthermore, we demonstrate that the mutated ZFYVE27 protein shows an aberrant intracellular pattern in its tubular structure and that its interaction with spastin is severely affected. We postulate that this specific mutation in ZFYVE27 affects neuronal intracellular trafficking in the corticospinal tract, which is consistent with the pathology of HSP.
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Affiliation(s)
- Ashraf U Mannan
- Institute of Human Genetics, University of Goettingen, Heinrich-Dueker Weg 12, D-37073, Goettingen, Germany.
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Wattenberg BW, Pitson SM, Raben DM. The sphingosine and diacylglycerol kinase superfamily of signaling kinases: localization as a key to signaling function. J Lipid Res 2006; 47:1128-39. [PMID: 16520486 DOI: 10.1194/jlr.r600003-jlr200] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The sphingosine and diacylglycerol kinases form a superfamily of structurally related lipid signaling kinases. One of the striking features of these kinases is that although they are clearly involved in agonist-mediated signaling, this signaling is accomplished with only a moderate (and sometimes no) increase in the enzymatic activity of the enzymes. Here, we summarize findings that indicate that signaling by these kinases is strongly dependent on their localization to specific intracellular sites rather than on increases in enzyme activity. Both the substrates and products of these enzymes are bioactive lipids. Moreover, many of the metabolic enzymes that act on these lipids are found in specific organelles. Therefore, changes in the membrane localization of these signaling kinases have profound effects not only on the production of signaling lipid phosphates but also on the metabolism of the upstream signaling lipids.
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Taha TA, Hannun YA, Obeid LM. Sphingosine kinase: biochemical and cellular regulation and role in disease. BMB Rep 2006; 39:113-31. [PMID: 16584625 DOI: 10.5483/bmbrep.2006.39.2.113] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Sphingolipids have emerged as molecules whose metabolism is regulated leading to generation of bioactive products including ceramide, sphingosine, and sphingosine-1-phosphate. The balance between cellular levels of these bioactive products is increasingly recognized to be critical to cell regulation; whereby, ceramide and sphingosine cause apoptosis and growth arrest phenotypes, and sphingosine-1-phosphate mediates proliferative and angiogenic responses. Sphingosine kinase is a key enzyme in modulating the levels of these lipids and is emerging as an important and regulated enzyme. This review is geared at mechanisms of regulation of sphingosine kinase and the coming to light of its role in disease.
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Affiliation(s)
- Tarek Assad Taha
- Department of Medicine, Medical University of South Carolina, USA
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43
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Soderblom C, Blackstone C. Traffic accidents: Molecular genetic insights into the pathogenesis of the hereditary spastic paraplegias. Pharmacol Ther 2006; 109:42-56. [PMID: 16005518 DOI: 10.1016/j.pharmthera.2005.06.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 06/06/2005] [Indexed: 12/11/2022]
Abstract
The hereditary spastic paraplegias (HSPs) comprise a clinically and genetically diverse group of inherited neurological disorders in which the primary manifestation is progressive spasticity and weakness of the lower limbs. The identification of over 25 genetic loci and 11 gene products for these disorders has yielded new insights into the molecular pathways involved in the pathogenesis of HSPs. In particular, causative mutations in proteins implicated in mitochondrial function, intracellular transport and trafficking, axonal development, and myelination have been identified. In many cases, the proper intracellular trafficking and distribution of molecules and organelles are ultimately thought to be involved in HSP pathogenesis. In fact, deficits in intracellular cargo trafficking and transport are concordant with the length dependence of the distal axonopathy of upper motor neurons observed in HSP patients. Through a better understanding of the functions of the HSP gene products, novel therapeutic targets for treatment and prevention are being identified.
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Affiliation(s)
- Cynthia Soderblom
- Cellular Neurology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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Kihara A, Anada Y, Igarashi Y. Mouse sphingosine kinase isoforms SPHK1a and SPHK1b differ in enzymatic traits including stability, localization, modification, and oligomerization. J Biol Chem 2005; 281:4532-9. [PMID: 16368679 DOI: 10.1074/jbc.m510308200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sphingosine kinases catalyze the production of the bioactive lipid molecule sphingosine 1-phosphate. Mice have two isoforms of sphingosine kinase type 1, SPHK1a and SPHK1b. In addition to the previously reported difference in their enzyme activities, we have found that these isoforms differ in several enzymatic characteristics. First, SPHK1b is unstable, whereas SPHK1a is highly stable. Degradation of SPHK1b occurs at the membrane and is inhibited by a proteasome inhibitor. Second, only SPHK1b exhibits abnormal mobility on SDS-PAGE, probably due to its SDS-resistant structure. Third, SPHK1a and SPHK1b are predominantly detected in the soluble and membrane fractions, respectively, when their degradation is inhibited. Fourth, only SPHK1b is modified with lipid, on its unique Cys residues (Cys-4 and Cys-5). Site-directed mutagenesis at these Cys residues resulted in increased sphingosine kinase activity, suggesting that the modification is inhibitory to the enzyme. Finally, SPHK1b tends to form homo-oligomers, whereas most SPHK1a is presented as monomers. We have also determined that the lipid modification of SPHK1b is involved in its homo-oligomerization. Thus, although these two proteins differ only in a few N-terminal amino acid residues, their enzymatic traits are extremely different.
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Affiliation(s)
- Akio Kihara
- Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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Sano T, Kihara A, Kurotsu F, Iwaki S, Igarashi Y. Regulation of the Sphingoid Long-chain Base Kinase Lcb4p by Ergosterol and Heme. J Biol Chem 2005; 280:36674-82. [PMID: 16141212 DOI: 10.1074/jbc.m503147200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sphingoid long-chain base 1-phosphates (LCBPs) are widely conserved, bioactive lipid molecules. In yeast, LCBPs are known to be involved in several cellular responses such as heat shock resistance and Ca(2+) mobilization, although their target molecules and signaling pathways remain unclear. To identify genes involved in LCBP signaling and in regulation of LCBP synthesis, we performed transposon mutagenesis in cells lacking the LCBP lyase DPL1 and LCBP phosphatase LCB3 genes and screened for phytosphingosine-resistant clones. Further isolation and identification revealed eight genes (PBP1, HEM14, UFD4, HMG1, TPS1, KES1, WHI2, and ERG5), in addition to the previously characterized LCB4 and PDR5 genes, that are involved in phytosphingosine resistance. Of these eight, four are ergosterol-related genes (HEM14, HMG1, KES1, and ERG5). We also demonstrated that protein expression of the long-chain base kinase Lcb4p was reduced in Deltahem14 and Deltahmg1 cells, likely as a consequence of decreased activity of the heme-dependent transcription factor Hap1p. In addition, phosphorylation of Lcb4p was decreased in all the ergosterol-related mutants isolated and other ergosterol mutants constructed (Deltaerg2, Deltaerg3, and Deltaerg6). Finally, plasma membrane localization of Lcb4p was found to be reduced in Deltaerg6 cells. These results suggest that changes in sterol composition affect the phosphorylation of Lcb4p because of the altered localization. The other genes isolated (PBP1, UFD4, TPS1, and WHI2) may be involved in LCBP signaling.
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Affiliation(s)
- Takamitsu Sano
- Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-choume, Kita-ku, Sapporo 060-0812, Japan
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Stahelin RV, Hwang JH, Kim JH, Park ZY, Johnson KR, Obeid LM, Cho W. The mechanism of membrane targeting of human sphingosine kinase 1. J Biol Chem 2005; 280:43030-8. [PMID: 16243846 DOI: 10.1074/jbc.m507574200] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sphingosine 1-phosphate is a bioactive sphingolipid that regulates cell growth and suppresses programmed cell death. The biosynthesis of sphingosine 1-phosphate is catalyzed by sphingosine kinase (SK) but the mechanism by which the subcellular localization and activity of SK is regulated in response to various stimuli is not fully understood. To elucidate the origin and structural determinant of the specific subcellular localization of SK, we performed biophysical and cell studies of human SK1 (hSK1) and selected mutants. In vitro measurements showed that hSK1 selectively bound phosphatidylserine over other anionic phospholipids and strongly preferred the plasma membrane-mimicking membrane to other cellular membrane mimetics. Mutational analysis indicates that conserved Thr54 and Asn89 in the putative membrane-binding surface are essential for lipid selectivity and membrane targeting both in vitro and in the cell. Also, phosphorylation of Ser225 enhances the membrane affinity and plasma membrane selectivity of hSK1, presumably by modulating the interaction of Thr54 and Asn89 with the membrane. Collectively, these studies suggest that the specific plasma membrane localization and activation of SK1 is mediated largely by specific lipid-protein interactions.
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Affiliation(s)
- Robert V Stahelin
- Department of Chemistry, University of Illinois, Chicago, Illinois 60607, USA
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Okada T, Ding G, Sonoda H, Kajimoto T, Haga Y, Khosrowbeygi A, Gao S, Miwa N, Jahangeer S, Nakamura SI. Involvement of N-terminal-extended Form of Sphingosine Kinase 2 in Serum-dependent Regulation of Cell Proliferation and Apoptosis. J Biol Chem 2005; 280:36318-25. [PMID: 16103110 DOI: 10.1074/jbc.m504507200] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sphingosine kinase (SPHK) 1 is implicated in the regulation of cell proliferation and anti-apoptotic processes by catalyzing the formation of an important bioactive messenger, sphingosine 1-phosphate. Unlike the proliferative action of SPHK1, another isozyme, SPHK2, has been shown to possess anti-proliferative or pro-apoptotic action. Molecular mechanisms of SPHK2 action, however, are largely unknown. The present studies were undertaken to characterize the N-terminal-extended form of SPHK2 (SPHK2-L) by comparing it with the originally reported form, SPHK2-S. Real-time quantitative PCR analysis revealed that SPHK2-L mRNA is the major form in several human cell lines and tissues. From sequence analyses it was concluded that SPHK2-L is a species-specific isoform that is expressed in human but not in mouse. At the protein level it has been demonstrated by immunoprecipitation studies that SPHK2-L is the major isoform in human hepatoma HepG2 cells. SPHK2-L, when expressed in human embryonic kidney (HEK) 293 cells, did not show any inhibition of DNA synthesis in the presence of serum, whereas it showed marked inhibition in the absence of serum. Moreover, serum deprivation resulted in the translocation of SPHK2-L into the nuclei. In addition, serum deprivation induced SPHK2-L expression in HEK293 cells. Furthermore, suppression of SPHK2 by small interfering RNA treatment prevented serum deprivation- or drug-induced apoptosis in HEK293 cells. Taken together, these results indicate that a major form of SPHK2 splice variant, SPHK2-L, in human cells does not inhibit DNA synthesis under normal conditions and that SPHK2-L accumulation in the nucleus induced by serum deprivation may be involved in the cessation of cell proliferation or apoptosis depending on the cell type.
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Affiliation(s)
- Taro Okada
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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Baumruker T, Bornancin F, Billich A. The role of sphingosine and ceramide kinases in inflammatory responses. Immunol Lett 2005; 96:175-85. [PMID: 15585321 DOI: 10.1016/j.imlet.2004.09.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Accepted: 09/03/2004] [Indexed: 12/20/2022]
Abstract
The 1-phosphates of sphingosine and ceramide (S1P and C1P) have emerged as key representatives of a new group of lipid signalling molecules. S1P is known to act both as an extracellular mediator and as an intracellular 'second messenger,' while C1P currently is only known for its intracellular actions. Therefore, sphingosine and ceramide kinases, the enzymes involved in the generation of these lipid mediators, are now in the spotlight. This review summarizes current information on structure, localization, substrate specificity, activation, and binding partners of these kinases, and then focuses on discoveries in relation to immune cell regulation and inflammation, addressing in particular mast cell activation and degranulation, IL-12 signalling, prostaglandin biosynthesis, monocyte activation, and neutrophil priming.
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Affiliation(s)
- Thomas Baumruker
- Novartis Institute for BioMedical Research Vienna, Brunner Strasse 59, A-1235 Vienna, Austria.
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Mastrandrea LD, Sessanna SM, Laychock SG. Sphingosine kinase activity and sphingosine-1 phosphate production in rat pancreatic islets and INS-1 cells: response to cytokines. Diabetes 2005; 54:1429-36. [PMID: 15855330 DOI: 10.2337/diabetes.54.5.1429] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sphingosine-1 phosphate (S1P) is a bioactive sphingolipid with the potential to mobilize Ca2+, to inhibit apoptosis, and to promote mitogenesis. Sphingosine kinase (SPHK) and S1P were characterized in INS-1 insulinoma cells and isolated rat islets of Langerhans. SPHK activity increased in INS-1 cell homogenates treated with interleukin-1beta (IL-1beta) or tumor necrosis factor-alpha (TNF-alpha), and responses were additive. IL-1beta or TNF-alpha increased islet SPHK activity within 15 min to 1 h; activity remained elevated after 8 h. SPHK2 was the predominant active isoform in INS-1 cells; little or no SPHK1 activity was detected. Cytokines increased endogenous S1P biosynthesis in 32P(i)-prelabeled INS-1 cells, and cycloheximide inhibited the response after 8 h, suggesting that protein synthesis mediated the response. There was no [32P]S1P release from cells. Compared with basal values, IL-1beta and TNF-alpha induced increases in SPHK1a mRNA levels relative to 18S ribosomal RNA in INS-1 cells within 1 h; relative SPHK2 mRNA levels were unchanged after cytokine treatment. IL-1beta, but not TNF-alpha, induced relative SPHK1a mRNA expression levels within 1 h in islets, whereas SPHK2 mRNA levels were unchanged. Thus, IL-1beta and TNF-alpha induced an early and sustained increase in SPHK activity in INS-1 cells and isolated islets, suggesting that S1P plays a role in the pathological response of pancreatic beta-cells to cytokines.
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Affiliation(s)
- Lucy D Mastrandrea
- Department of Pharmacology and Toxicology, The State University of New York at Buffalo, Buffalo, NY, USA
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Fujita T, Okada T, Hayashi S, Jahangeer S, Miwa N, Nakamura SI. Delta-catenin/NPRAP (neural plakophilin-related armadillo repeat protein) interacts with and activates sphingosine kinase 1. Biochem J 2005; 382:717-23. [PMID: 15193146 PMCID: PMC1133830 DOI: 10.1042/bj20040141] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2004] [Revised: 06/03/2004] [Accepted: 06/14/2004] [Indexed: 11/17/2022]
Abstract
Sphingosine kinase (SPHK) is a key enzyme catalysing the formation of sphingosine 1-phosphate (SPP), a lipid messenger that is implicated in the regulation of a wide variety of important cellular events acting through intracellular, as well as extracellular, mechanisms. However, the molecular mechanism of intracellular actions of SPP remains unclear. Here, we have identified delta-catenin/NPRAP (neural plakophilin-related armadillo repeat protein) as a potential binding partner for SPHK1 by yeast two-hybrid screening. From co-immunoprecipitation analyses, the C-terminal portion of delta-catenin/NPRAP containing the seventh to tenth armadillo repeats was found to be required for interaction with SPHK1. Endogenous delta-catenin/NPRAP was co-localized with endogenous SPHK1 and transfected delta-catenin/NPRAP was co-localized with transfected SPHK1 in dissociated rat hippocampal neurons. MDCK (Madin-Darby canine kidney) cells stably expressing delta-catenin/NPRAP contained elevated levels of intracellular SPP. In a purified system delta-catenin/NPRAP stimulated SPHK1 in a dose-dependent manner. Furthermore, delta-catenin/NPRAP-induced increased cell motility in MDCK cells was completely inhibited by dimethylsphingosine, a specific inhibitor of SPHK1. These results strongly suggest that at least some of delta-catenin/NPRAP functions, including increased cell motility, are mediated by an SPHK-SPP signalling pathway.
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Affiliation(s)
- Toshitada Fujita
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Taro Okada
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Shun Hayashi
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Saleem Jahangeer
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Noriko Miwa
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Shun-ichi Nakamura
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
- To whom correspondence should be addressed (email )
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