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Fung SYS, Xǔ XJ, Wu M. Nonlinear dynamics in phosphoinositide metabolism. Curr Opin Cell Biol 2024; 88:102373. [PMID: 38797149 PMCID: PMC11186694 DOI: 10.1016/j.ceb.2024.102373] [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: 02/09/2024] [Revised: 04/26/2024] [Accepted: 05/01/2024] [Indexed: 05/29/2024]
Abstract
Phosphoinositides broadly impact membrane dynamics, signal transduction and cellular physiology. The orchestration of signaling complexity by this seemingly simple metabolic pathway remains an open question. It is increasingly evident that comprehending the complexity of the phosphoinositides metabolic network requires a systems view based on nonlinear dynamics, where the products of metabolism can either positively or negatively modulate enzymatic function. These feedback and feedforward loops may be paradoxical, leading to counterintuitive effects. In this review, we introduce the framework of nonlinear dynamics, emphasizing distinct dynamical regimes such as the excitable state, oscillations, and mixed-mode oscillations-all of which have been experimentally observed in phosphoinositide metabolisms. We delve into how these dynamical behaviors arise from one or multiple network motifs, including positive and negative feedback loops, coherent and incoherent feedforward loops. We explore the current understanding of the molecular circuits responsible for these behaviors. While mapping these circuits presents both conceptual and experimental challenges, redefining cellular behavior based on dynamical state, lipid fluxes, time delay, and network topology is likely essential for a comprehensive understanding of this fundamental metabolic network.
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Affiliation(s)
- Suet Yin Sarah Fung
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8002, USA
| | - X J Xǔ
- Department of Physics, Yale University, New Haven, CT, 06511, USA
| | - Min Wu
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8002, USA.
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The Role of Membrane Affinity and Binding Modes in Alpha-Synuclein Regulation of Vesicle Release and Trafficking. Biomolecules 2022; 12:biom12121816. [PMID: 36551244 PMCID: PMC9775087 DOI: 10.3390/biom12121816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/02/2022] [Accepted: 11/27/2022] [Indexed: 12/12/2022] Open
Abstract
Alpha-synuclein is a presynaptic protein linked to Parkinson's disease with a poorly characterized physiological role in regulating the synaptic vesicle cycle. Using RBL-2H3 cells as a model system, we earlier reported that wild-type alpha-synuclein can act as both an inhibitor and a potentiator of stimulated exocytosis in a concentration-dependent manner. The inhibitory function is constitutive and depends on membrane binding by the helix-2 region of the lipid-binding domain, while potentiation becomes apparent only at high concentrations. Using structural and functional characterization of conformationally selective mutants via a combination of spectroscopic and cellular assays, we show here that binding affinity for isolated vesicles similar in size to synaptic vesicles is a primary determinant of alpha-synuclein-mediated potentiation of vesicle release. Inhibition of release is sensitive to changes in the region linking the helix-1 and helix-2 regions of the N-terminal lipid-binding domain and may require some degree of coupling between these regions. Potentiation of release likely occurs as a result of alpha-synuclein interactions with undocked vesicles isolated away from the active zone in internal pools. Consistent with this, we observe that alpha-synuclein can disperse vesicles from in vitro clusters organized by condensates of the presynaptic protein synapsin-1.
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TRPV4 activates the Cdc42/N-wasp pathway to promote glioblastoma invasion by altering cellular protrusions. Sci Rep 2020; 10:14151. [PMID: 32843668 PMCID: PMC7447819 DOI: 10.1038/s41598-020-70822-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 08/04/2020] [Indexed: 12/15/2022] Open
Abstract
The invasion ability of glioblastoma (GBM) causes tumor cells to infiltrate the surrounding brain parenchyma and leads to poor outcomes. Transient receptor potential vanilloid 4 (TRPV4) exhibits a remarkable role in cancer cell motility, but the contribution of TRPV4 to glioblastoma metastasis is not fully understood. Here, we reported that TRPV4 expression was significantly elevated in malignant glioma compared to normal brain and low-grade glioma, and TRPV4 expression was negatively correlated with the prognosis of glioma patients. Functionally, stimulation of TRPV4 promoted glioblastoma cell migration and invasion, and repression of TRPV4 hindered the migration and invasion of glioblastoma cells in vitro. Molecularly, TRPV4 strongly colocalized and interacted with skeletal protein-F-actin at cellular protrusions, and TRPV4 regulated the formation of invadopodia and filopodia in glioblastoma cells. Furthermore, the Cdc42/N-wasp axis mediated the effect of TRPV4-regulated cellular protrusions and invasion. Foremost, TRPV4 inhibitor treatment or downregulation of TRPV4 significantly reduced the invasion-growth of subcutaneously and intracranially transplanted glioblastoma in mice. In conclusion, the TRPV4/Cdc42/wasp signaling axis regulates cellular protrusion formation in glioblastoma cells and influences the invasion-growth phenotype of glioblastoma in vivo. TRPV4 may serve as a prognostic factor and specific therapeutic target for GBM patients.
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Ramezani M, Wilkes MM, Das T, Holowka D, Eliezer D, Baird B. Regulation of exocytosis and mitochondrial relocalization by Alpha-synuclein in a mammalian cell model. NPJ PARKINSONS DISEASE 2019; 5:12. [PMID: 31263746 PMCID: PMC6597712 DOI: 10.1038/s41531-019-0084-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/23/2019] [Indexed: 12/24/2022]
Abstract
We characterized phenotypes in RBL-2H3 mast cells transfected with human alpha synuclein (a-syn) using stimulated exocytosis of recycling endosomes as a proxy for similar activities of synaptic vesicles in neurons. We found that low expression of a-syn inhibits stimulated exocytosis and that higher expression causes slight enhancement. NMR measurements of membrane interactions correlate with these functional effects: they are eliminated differentially by mutants that perturb helical structure in the helix 1 (A30P) or NAC/helix-2 (V70P) regions of membrane-bound a-syn, but not by other PD-associated mutants or C-terminal truncation. We further found that a-syn (but not A30P or V70P mutants) associates weakly with mitochondria, but this association increases markedly under conditions of cellular stress. These results highlight the importance of specific structural features of a-syn in regulating vesicle release, and point to a potential role for a-syn in perturbing mitochondrial function under pathological conditions.
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Affiliation(s)
- Meraj Ramezani
- 1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
| | - Marcus M Wilkes
- 1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
| | - Tapojyoti Das
- 2Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065 USA
| | - David Holowka
- 1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
| | - David Eliezer
- 2Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065 USA
| | - Barbara Baird
- 1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
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Bouffard J, Cecchetelli AD, Clifford C, Sethi K, Zaidel-Bar R, Cram EJ. The RhoGAP SPV-1 regulates calcium signaling to control the contractility of the Caenorhabditis elegans spermatheca during embryo transits. Mol Biol Cell 2019; 30:907-922. [PMID: 30726159 PMCID: PMC6589790 DOI: 10.1091/mbc.e18-10-0633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/25/2019] [Accepted: 01/31/2019] [Indexed: 01/30/2023] Open
Abstract
Contractility of the nonmuscle and smooth muscle cells that comprise biological tubing is regulated by the Rho-ROCK (Rho-associated protein kinase) and calcium signaling pathways. Although many molecular details about these signaling pathways are known, less is known about how they are coordinated spatiotemporally in biological tubes. The spermatheca of the Caenorhabditis elegans reproductive system enables study of the signaling pathways regulating actomyosin contractility in live adult animals. The RhoGAP (GTPase--activating protein toward Rho family small GTPases) SPV-1 was previously identified as a negative regulator of RHO-1/Rho and spermathecal contractility. Here, we uncover a role for SPV-1 as a key regulator of calcium signaling. spv-1 mutants expressing the calcium indicator GCaMP in the spermatheca exhibit premature calcium release, elevated calcium levels, and disrupted spatial regulation of calcium signaling during spermathecal contraction. Although RHO-1 is required for spermathecal contractility, RHO-1 does not play a significant role in regulating calcium. In contrast, activation of CDC-42 recapitulates many aspects of spv-1 mutant calcium signaling. Depletion of cdc-42 by RNA interference does not suppress the premature or elevated calcium signal seen in spv-1 mutants, suggesting other targets remain to be identified. Our results suggest that SPV-1 works through both the Rho-ROCK and calcium signaling pathways to coordinate cellular contractility.
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Affiliation(s)
- Jeff Bouffard
- Department of Bioengineering, Northeastern University, Boston, MA 02143
| | | | - Coleman Clifford
- Department of Biology, Northeastern University, Boston, MA 02143
| | - Kriti Sethi
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Ronen Zaidel-Bar
- Mechanobiology Institute, National University of Singapore, Singapore 117411
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Erin J. Cram
- Department of Biology, Northeastern University, Boston, MA 02143
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Abdellah N, van Remoortel S, Mohey-Elsaeed O, Mustafa MN, Ahmed YA, Timmermans JP, Buckinx R. Neuropeptide AF Induces Piecemeal Degranulation in Murine Mucosal Mast Cells: A New Mediator in Neuro-Immune Communication in the Intestinal Lamina Propria? Anat Rec (Hoboken) 2018; 301:1103-1114. [DOI: 10.1002/ar.23780] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/25/2017] [Accepted: 12/11/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Nada Abdellah
- Histology Department, Faculty of Veterinary Medicine; Sohag University; Sohag Egypt
- Laboratory of Cell Biology & Histology, University of Antwerp; Antwerp Belgium
| | | | - Omnia Mohey-Elsaeed
- Laboratory of Cell Biology & Histology, University of Antwerp; Antwerp Belgium
- Department of Cytology and Histology, Faculty of Veterinary Medicine; Cairo University; Giza 12122 Egypt
| | - Mohamed-Nabil Mustafa
- Department of Anatomy and Histology, Faculty of Veterinary Medicine; Assiut University; Assiut Egypt
| | - Yasser A. Ahmed
- Department of Histology, Faculty of Veterinary Medicine; South Valley University; Qena Egypt
| | | | - Roeland Buckinx
- Laboratory of Cell Biology & Histology, University of Antwerp; Antwerp Belgium
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Holowka D, Wilkes M, Stefan C, Baird B. Roles for Ca2+ mobilization and its regulation in mast cell functions: recent progress. Biochem Soc Trans 2016; 44:505-9. [PMID: 27068962 PMCID: PMC5293407 DOI: 10.1042/bst20150273] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Indexed: 12/21/2022]
Abstract
Ca(2+)mobilization in response to cross-linking of IgE bound to its high affinity receptor, FcεRI, on mast cells is central to immune allergic responses. Stimulated tyrosine phosphorylation caused by this cross-linking activates store-operated Ca(2+)entry that results in sustained Ca(2+)oscillations dependent on Rho family GTPases and phosphoinositide synthesis. Coupling of the endoplasmic reticulum (ER) Ca(2+)sensor, stromal interaction molecule 1 (STIM1), to the Ca(2+)-selective channel, Orai1, is regulated by these elements and depends on membrane organization, both at the plasma membrane and at the ER. Mitochondria also contribute to the regulation of Ca(2+)mobilization, and we describe recent evidence that the ER membrane protein vesicle-associated membrane protein-associated protein (VAP) plays a significant role in the coupling between ER and mitochondria in this process. In addition to granule exocytosis, Ca(2+)mobilization in these cells also contributes to stimulated outward trafficking of recycling endosomes and to antigen-stimulated chemotaxis, and it is pathologically regulated by protozoan parasitic invasion.
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Affiliation(s)
- David Holowka
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, U.S.A.
| | - Marcus Wilkes
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, U.S.A
| | - Christopher Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, WC1E 6BT London, U.K
| | - Barbara Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, U.S.A
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Roles for lipid heterogeneity in immunoreceptor signaling. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:830-836. [PMID: 26995463 DOI: 10.1016/j.bbalip.2016.03.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 03/12/2016] [Accepted: 03/14/2016] [Indexed: 11/22/2022]
Abstract
Immune receptors that specifically recognize foreign antigens to activate leukocytes in adaptive immune responses belong to a family of multichain cell surface proteins. All of these contain immunoreceptor tyrosine-based activation motifs in one or more subunits that initiate signaling cascades following stimulated tyrosine phosphorylation by Src-family kinases. As highlighted in this review, lipids participate in this initial activation step, as well as in more downstream signaling steps. We summarize evidence for cholesterol-dependent ordered lipids serving to regulate the store-operated Ca(2+) channel, Orai1, and we describe the sensitivity of Orai1 coupling to the ER Ca(2+) sensor, STIM1, to inhibition by polyunsaturated fatty acids. Phosphoinositides play key roles in regulating STIM1-Orai1 coupling, as well as in the stimulated Ca(2+) oscillations that are a consequence of IgE receptor signaling in mast cells. They also participate in the coupling between the plasma membrane and the actin cytoskeleton, which regulates immune receptor responses in T cells, B cells, and mast cells, both positively and negatively, depending on the cellular context. Recent studies show that other phospholipids with mostly saturated acylation also participate in coupling between receptors and the actin cytoskeleton. Lipid heterogeneity is a central feature of the intimate relationship between the plasma membrane and the actin cytoskeleton. The detailed nature of these interactions and how they are dynamically regulated to initiate and propagate receptor-mediated cell signaling are challenging questions for further investigation. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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Abstract
Dramatic elevations in the serum IgE level are seen both in polygenic allergic diseases such as atopic dermatitis and food allergy, and in a growing list of monogenic primary immune deficiencies (PIDs). Although the IgE produced in patients with PID has generally been considered to be driven by dysregulated IL-4 production and thus lack antigen specificity, in fact allergen-specific IgE can be detected by skin and serum testing in many of these patients. However, perhaps not surprisingly given the distinct immunologic pathways involved, the patterns of allergic disease and atopic sensitization vary widely between syndromes, leading to strikingly different clinical phenotypes.
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Affiliation(s)
- Monica G Lawrence
- University of Virginia Asthma and Allergic Diseases Center, PO Box 801355, Charlottesville, VA, 22908, USA.
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Li ZY, Jiang WY, Cui ZJ. An essential role of NAD(P)H oxidase 2 in UVA-induced calcium oscillations in mast cells. Photochem Photobiol Sci 2015; 14:414-28. [PMID: 25460548 DOI: 10.1039/c4pp00304g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Solar UVA radiation (320-400 nm) is known to have immunomodulatory effects, but the detailed mechanisms involved are not fully elucidated. UVA irradiation has been shown to induce calcium oscillations in rat peritoneal mast cells due to NAD(P)H oxidase (NOX) activation, but the specific NOX isoforms have not been identified. In the present work effects of UVA irradiation were investigated in isolated rat peritoneal mast cells, in cultured rat mast cell line RBL-2H3, and in mouse bone marrow-derived mast cells (BMMC). It was found that UVA irradiation by alternate 340/380 nm (3.2-5.6 μW cm(-2)) or by LED (380 nm, 80 μW cm(-2)) induced calcium oscillations in isolated rat peritoneal mast cells, in RBL-2H3, and in BMMC. Such UVA-induced calcium oscillations resembled closely those induced by surface IgE receptor (FcεRI) activation. It was found that RBL-2H3 expressed high levels of gp91(phox) (NOX2), p22(phox), p67(phox), p47(phox), p40(phox), Rac1, Rac2, moderate levels of DUOX2, but did not express NOX1, NOX3, NOX4, or DUOX1. The specific cellular localizations of gp91(phox) (NOX2), p22(phox), p47(phox), p67(phox), p40(phox) and Rac1/2 were confirmed by immunocytochemistry. UVA-induced reactive oxygen species (ROS) production in RBL-2H3 was completely suppressed by the NOX inhibitor diphenyleneiodonium chloride (DPI) or by the antioxidant N-acetyl-l-cysteine (NAC). siRNA suppression of gp91(phox) (NOX2), p22(phox) and p47(phox) expression inhibited markedly UVA-induced calcium oscillations, ROS and IL-6/LTC4 production in RBL-2H3. Taken together these data indicate that NOX2 plays an essential role in UVA irradiation-induced calcium oscillations, ROS and mediator production in mast cells.
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Affiliation(s)
- Zhi Ying Li
- Institute of Cell Biology, Beijing Normal University, Beijing 100875, China.
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