1
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Wang Q, Wolf A, Ozkan S, Richert L, Mely Y, Chasserot-Golaz S, Ory S, Gasman S, Vitale N. V-ATPase modulates exocytosis in neuroendocrine cells through the activation of the ARNO-Arf6-PLD pathway and the synthesis of phosphatidic acid. Front Mol Biosci 2023; 10:1163545. [PMID: 37091866 PMCID: PMC10119424 DOI: 10.3389/fmolb.2023.1163545] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/23/2023] [Indexed: 04/25/2023] Open
Abstract
Although there is mounting evidence indicating that lipids serve crucial functions in cells and are implicated in a growing number of human diseases, their precise roles remain largely unknown. This is particularly true in the case of neurosecretion, where fusion with the plasma membrane of specific membrane organelles is essential. Yet, little attention has been given to the role of lipids. Recent groundbreaking research has emphasized the critical role of lipid localization at exocytotic sites and validated the essentiality of fusogenic lipids, such as phospholipase D (PLD)-generated phosphatidic acid (PA), during membrane fusion. Nevertheless, the regulatory mechanisms synchronizing the synthesis of these key lipids and neurosecretion remain poorly understood. The vacuolar ATPase (V-ATPase) has been involved both in vesicle neurotransmitter loading and in vesicle fusion. Thus, it represents an ideal candidate to regulate the fusogenic status of secretory vesicles according to their replenishment state. Indeed, the cytosolic V1 and vesicular membrane-associated V0 subdomains of V-ATPase were shown to dissociate during the stimulation of neurosecretory cells. This allows the subunits of the vesicular V0 to interact with different proteins of the secretory machinery. Here, we show that V0a1 interacts with the Arf nucleotide-binding site opener (ARNO) and promotes the activation of the Arf6 GTPase during the exocytosis in neuroendocrine cells. When the interaction between V0a1 and ARNO was disrupted, it resulted in the inhibition of PLD activation, synthesis of phosphatidic acid during exocytosis, and changes in the timing of fusion events. These findings indicate that the separation of V1 from V0 could function as a signal to initiate the ARNO-Arf6-PLD1 pathway and facilitate the production of phosphatidic acid, which is essential for effective exocytosis in neuroendocrine cells.
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Affiliation(s)
- Qili Wang
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Alexander Wolf
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Sebahat Ozkan
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Ludovic Richert
- Laboratoire de Bioimagerie et Pathologies, Faculté de Pharmacie, CNRS UMR and Université de Strasbourg, Strasbourg, France
| | - Yves Mely
- Laboratoire de Bioimagerie et Pathologies, Faculté de Pharmacie, CNRS UMR and Université de Strasbourg, Strasbourg, France
| | - Sylvette Chasserot-Golaz
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Stéphane Ory
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Stéphane Gasman
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
- *Correspondence: Nicolas Vitale,
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2
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RhoG deficiency abrogates cytotoxicity of human lymphocytes and causes hemophagocytic lymphohistiocytosis. Blood 2021; 137:2033-2045. [PMID: 33513601 DOI: 10.1182/blood.2020008738] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 01/11/2021] [Indexed: 11/20/2022] Open
Abstract
Exocytosis of cytotoxic granules (CG) by lymphocytes is required for the elimination of infected and malignant cells. Impairments in this process underly a group of diseases with dramatic hyperferritinemic inflammation termed hemophagocytic lymphohistiocytosis (HLH). Although genetic and functional studies of HLH have identified proteins controlling distinct steps of CG exocytosis, the molecular mechanisms that spatiotemporally coordinate CG release remain partially elusive. We studied a patient exhibiting characteristic clinical features of HLH associated with markedly impaired cytotoxic T lymphocyte (CTL) and natural killer (NK) cell exocytosis functions, who beared biallelic deleterious mutations in the gene encoding the small GTPase RhoG. Experimental ablation of RHOG in a model cell line and primary CTLs from healthy individuals uncovered a hitherto unappreciated role of RhoG in retaining CGs in the vicinity of the plasma membrane (PM), a fundamental prerequisite for CG exocytotic release. We discovered that RhoG engages in a protein-protein interaction with Munc13-4, an exocytosis protein essential for CG fusion with the PM. We show that this interaction is critical for docking of Munc13-4+ CGs to the PM and subsequent membrane fusion and release of CG content. Thus, our study illuminates RhoG as a novel essential regulator of human lymphocyte cytotoxicity and provides the molecular pathomechanism behind the identified here and previously unreported genetically determined form of HLH.
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3
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Cheng K, Larabee SM, Tolaymat M, Hanscom M, Shang AC, Schledwitz A, Hu S, Drachenberg CB, Zhan M, Chahdi A, Raufman JP. Targeted intestinal deletion of Rho guanine nucleotide exchange factor 7, βPIX, impairs enterocyte proliferation, villus maturation, and mucosal defenses in mice. Am J Physiol Gastrointest Liver Physiol 2021; 320:G627-G643. [PMID: 33566751 PMCID: PMC8238171 DOI: 10.1152/ajpgi.00415.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/01/2021] [Accepted: 02/10/2021] [Indexed: 01/31/2023]
Abstract
Rho guanine nucleotide exchange factors (RhoGEFs) regulate Rho GTPase activity and cytoskeletal and cell adhesion dynamics. βPix, a CDC42/RAC family RhoGEF encoded by ARHGEF7, is reported to modulate human colon cancer cell proliferation and postwounding restitution of rat intestinal epithelial monolayers. We hypothesized that βPix plays a role in maintaining intestinal epithelial homeostasis. To test this hypothesis, we examined βPix distribution in the human and murine intestine and created mice with intestinal epithelial-selective βPix deletion [βPixflox/flox/Tg(villin-Cre); Arhgef7 CKO mice]. Using Arhgef7 conditional knockout (CKO) and control mice, we investigated the consequences of βPix deficiency in vivo on intestinal epithelial and enteroid development, dextran sodium sulfate-induced mucosal injury, and gut permeability. In normal human and murine intestines, we observed diffuse cytoplasmic and moderate nuclear βPix immunostaining in enterocytes. Arhgef7 CKO mice were viable and fertile, with normal gross intestinal architecture but reduced small intestinal villus height, villus-to-crypt ratio, and goblet cells; small intestinal crypt cells had reduced Ki67 staining, compatible with impaired cell proliferation. Enteroids derived from control mouse small intestine were viable for more than 20 passages, but those from Arhgef7 CKO mice did not survive beyond 24 h despite addition of Wnt proteins or conditioned media from normal enteroids. Adding a Rho kinase (ROCK) inhibitor partially rescued CKO enteroid development. Compared with littermate control mice, dextran sodium sulfate-treated βPix-deficient mice lost more weight and had greater impairment of intestinal barrier function, and more severe colonic mucosal injury. These findings reveal βPix expression is important for enterocyte development, intestinal homeostasis, and resistance to toxic injury.NEW & NOTEWORTHY To explore the role of βPix, a guanine nucleotide exchange factor encoded by ARHGEF7, in intestinal development and physiology, we created mice with intestinal epithelial cell Arhgef7/βPix deficiency. We found βPix essential for normal small intestinal epithelial cell proliferation, villus development, and mucosal resistance to injury. Moreover, Rho kinase signaling mediated developmental arrest observed in enteroids derived from βPix-deficient small intestinal crypts. Our studies provide insights into the role Arhgef7/βPix plays in intestinal epithelial homeostasis.
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Affiliation(s)
- Kunrong Cheng
- Veterans Affairs Maryland Healthcare System, Baltimore, Maryland
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Shannon M Larabee
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Mazen Tolaymat
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Marie Hanscom
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Aaron C Shang
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Alyssa Schledwitz
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Shien Hu
- Veterans Affairs Maryland Healthcare System, Baltimore, Maryland
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Cinthia B Drachenberg
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Min Zhan
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ahmed Chahdi
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jean-Pierre Raufman
- Veterans Affairs Maryland Healthcare System, Baltimore, Maryland
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
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4
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Tanguy E, Wolf A, Montero-Hadjadje M, Gasman S, Bader MF, Vitale N. Phosphatidic acid: Mono- and poly-unsaturated forms regulate distinct stages of neuroendocrine exocytosis. Adv Biol Regul 2020; 79:100772. [PMID: 33288473 DOI: 10.1016/j.jbior.2020.100772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/16/2020] [Accepted: 11/25/2020] [Indexed: 10/22/2022]
Abstract
Lipids have emerged as important actors in an ever-growing number of key functions in cell biology over the last few years. Among them, glycerophospholipids are major constituents of cellular membranes. Because of their amphiphilic nature, phospholipids form lipid bilayers that are particularly useful to isolate cellular content from the extracellular medium, but also to define intracellular compartments. Interestingly, phospholipids come in different flavors based on their fatty acyl chain composition. Indeed, lipidomic analyses have revealed the presence in cellular membranes of up to 50 different species of an individual class of phospholipid, opening the possibility of multiple functions for a single class of phospholipid. In this review we will focus on phosphatidic acid (PA), the simplest phospholipid, that plays both structural and signaling functions. Among the numerous roles that have been attributed to PA, a key regulatory role in secretion has been proposed in different cell models. We review here the evidences that support the idea that mono- and poly-unsaturated PA control distinct steps in hormone secretion from neuroendocrine cells.
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Affiliation(s)
- Emeline Tanguy
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Alexander Wolf
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Maité Montero-Hadjadje
- Normandie Univ, UNIROUEN, INSERM, U1239, Laboratoire de Différenciation et Communication Neuronale et Neuroendocrine, Institut de Recherche et d'Innovation Biomédicale de Normandie, 76000, Rouen, France
| | - Stéphane Gasman
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Marie-France Bader
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Nicolas Vitale
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France.
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5
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Mono- and Poly-unsaturated Phosphatidic Acid Regulate Distinct Steps of Regulated Exocytosis in Neuroendocrine Cells. Cell Rep 2020; 32:108026. [DOI: 10.1016/j.celrep.2020.108026] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/16/2020] [Accepted: 07/21/2020] [Indexed: 12/21/2022] Open
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6
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Hormones Secretion and Rho GTPases in Neuroendocrine Tumors. Cancers (Basel) 2020; 12:cancers12071859. [PMID: 32664294 PMCID: PMC7408961 DOI: 10.3390/cancers12071859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 12/14/2022] Open
Abstract
Neuroendocrine tumors (NETs) belong to a heterogeneous group of neoplasms arising from hormone secreting cells. These tumors are often associated with a dysfunction of their secretory activity. Neuroendocrine secretion occurs through calcium-regulated exocytosis, a process that is tightly controlled by Rho GTPases family members. In this review, we compiled the numerous mutations and modification of expression levels of Rho GTPases or their regulators (Rho guanine nucleotide-exchange factors and Rho GTPase-activating proteins) that have been identified in NETs. We discussed how they might regulate neuroendocrine secretion.
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7
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Tanguy E, Wang Q, Vitale N. Role of Phospholipase D-Derived Phosphatidic Acid in Regulated Exocytosis and Neurological Disease. Handb Exp Pharmacol 2020; 259:115-130. [PMID: 30570690 DOI: 10.1007/164_2018_180] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Lipids play a vital role in numerous cellular functions starting from a structural role as major constituents of membranes to acting as signaling intracellular or extracellular entities. Accordingly, it has been known for decades that lipids, especially those coming from diet, are important to maintain normal physiological functions and good health. On the other side, the exact molecular nature of these beneficial or deleterious lipids, as well as their precise mode of action, is only starting to be unraveled. This recent improvement in our knowledge is largely resulting from novel pharmacological, molecular, cellular, and genetic tools to study lipids in vitro and in vivo. Among these important lipids, phosphatidic acid plays a unique and central role in a great variety of cellular functions. This review will focus on the proposed functions of phosphatidic acid generated by phospholipase D in the last steps of regulated exocytosis with a specific emphasis on hormonal and neurotransmitter release and its potential impact on different neurological diseases.
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Affiliation(s)
- Emeline Tanguy
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Qili Wang
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France.
- INSERM, Paris, Cedex 13, France.
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8
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Houy S, Nicolas G, Momboisse F, Malacombe M, Bader MF, Vitale N, Lecomte MC, Ory S, Gasman S. αII-spectrin controls calcium-regulated exocytosis in neuroendocrine chromaffin cells through neuronal Wiskott-Aldrich Syndrome protein interaction. IUBMB Life 2019; 72:544-552. [PMID: 31859439 DOI: 10.1002/iub.2217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 11/30/2019] [Indexed: 11/11/2022]
Abstract
Besides a fundamental structural role at the plasma membrane, spectrin- and actin-based skeletons have been proposed to participate in various processes including vesicular trafficking. Neuroendocrine cells release hormones and neuropeptides through calcium-regulated exocytosis, a process that is coordinated by a fine remodeling of the actin cytoskeleton. We describe here that calcium-regulated exocytosis is impaired in chromaffin and PC12 cells with reduced αII-spectrin expression levels. Using yeast two-hybrid screening, we show that neuronal Wiskott-Aldrich Syndrome protein (N-WASP) is a partner of the αII-spectrin SH3 domain and demonstrate that secretagogue-evoked N-WASP recruitment at cell periphery is blocked in the absence of αII-spectrin. Additionally, experiments performed with ectopically expressed αII-spectrin mutant unable to bind N-WASP indicated that the interaction between SH3 domain and N-WASP is pivotal for neuroendocrine secretion. Our results extend the list of spectrin interactors and strengthen the idea that αII-spectrin is an important scaffold protein that gathers crucial actin-related players of the exocytic machinery.
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Affiliation(s)
- Sébastien Houy
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
| | - Gaël Nicolas
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, Paris, France.,Laboratory of Excellence GR-EX, Paris, France
| | - Fanny Momboisse
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
| | - Magali Malacombe
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
| | - Marie-France Bader
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
| | - Nicolas Vitale
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
| | - Marie-Christine Lecomte
- Laboratory of Excellence GR-EX, Paris, France.,Biologie Intégrée du Globule Rouge UMR_S1134, Inserm, Université Paris Diderot, Paris, France.,Institut National de la Transfusion Sanguine, Université des Antilles, Paris, France
| | - Stéphane Ory
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
| | - Stéphane Gasman
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
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9
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Ho PY, Li H, Cheng L, Bhalla V, Fenton RA, Hallows KR. AMPK phosphorylation of the β 1Pix exchange factor regulates the assembly and function of an ENaC inhibitory complex in kidney epithelial cells. Am J Physiol Renal Physiol 2019; 317:F1513-F1525. [PMID: 31566435 DOI: 10.1152/ajprenal.00592.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The metabolic sensor AMP-activated protein kinase (AMPK) inhibits the epithelial Na+ channel (ENaC), a key regulator of salt reabsorption by the kidney and thus total body volume and blood pressure. Recent studies have suggested that AMPK promotes the association of p21-activated kinase-interacting exchange factor-β1 β1Pix, 14-3-3 proteins, and the ubiquitin ligase neural precursor cell expressed developmentally downregulated protein (Nedd)4-2 into a complex that inhibits ENaC by enhancing Nedd4-2 binding to ENaC and ENaC degradation. Functional β1Pix is required for ENaC inhibition by AMPK and promotes Nedd4-2 phosphorylation and stability in mouse kidney cortical collecting duct cells. Here, we report that AMPK directly phosphorylates β1Pix in vitro. Among several AMPK phosphorylation sites on β1Pix detected by mass spectrometry, Ser71 was validated as functionally significant. Compared with wild-type β1Pix, overexpression of a phosphorylation-deficient β1Pix-S71A mutant attenuated ENaC inhibition and the AMPK-activated interaction of both β1Pix and Nedd4-2 to 14-3-3 proteins in cortical collecting duct cells. Similarly, overexpression of a β1Pix-Δ602-611 deletion tract mutant unable to bind 14-3-3 proteins decreased the interaction between Nedd4-2 and 14-3-3 proteins, suggesting that 14-3-3 binding to β1Pix is critical for the formation of a β1Pix/Nedd4-2/14-3-3 complex. With expression of a general peptide inhibitor of 14-3-3-target protein interactions (R18), binding of both β1Pix and Nedd4-2 to 14-3-3 proteins was reduced, and AMPK-dependent ENaC inhibition was also attenuated. Altogether, our results demonstrate the importance of AMPK-mediated phosphorylation of β1Pix at Ser71, which promotes 14-3-3 interactions with β1Pix and Nedd4-2 to form a tripartite ENaC inhibitory complex, in the mechanism of ENaC regulation by AMPK.
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Affiliation(s)
- Pei-Yin Ho
- Division of Nephrology and Hypertension, Department of Medicine and USC/UKRO Kidney Research Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Hui Li
- Division of Nephrology and Hypertension, Department of Medicine and USC/UKRO Kidney Research Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Lei Cheng
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Vivek Bhalla
- Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Kenneth R Hallows
- Division of Nephrology and Hypertension, Department of Medicine and USC/UKRO Kidney Research Center, Keck School of Medicine, University of Southern California, Los Angeles, California
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10
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Godínez-Solís Y, Solís-Heredia MDJ, Roa-Espitia A, Parra-Forero LY, Hernández-González EO, Hernández-Ochoa I, Quintanilla-Vega B. Low concentrations of lead decrease the sperm fertilization ability by altering the acrosome reaction in mice. Toxicol Appl Pharmacol 2019; 380:114694. [PMID: 31356930 DOI: 10.1016/j.taap.2019.114694] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 11/17/2022]
Abstract
Lead (Pb) exposure at high concentrations is associated with poor sperm quality, acrosome alterations, and low fertilization rate. Sperm capacitation and the acrosome reaction (AR) are required for successful fertilization. Actin polymerization is crucial for correct capacitation, and small GTPases, such as RhoA, Rac1, and Cdc42, are involved. This study aimed to evaluate the effects of Pb on sperm fertilization ability, capacitation, AR, and the mechanisms involved in mice exposed to low Pb concentrations. CD1 mice were exposed to 0.01% Pb2+ for 45 days through their drinking water and their spermatozoa were collected from the cauda epididymis-vas deferens to evaluate the following: AR (oAR: initial, sAR: spontaneous, and iAR: induced) using the PNA-FITC assay, sperm capacitation (P-Tyr levels), actin polymerization (phalloidin-TRITC), MDA production (stress oxidative marker), the RhoA, Rac1, and Cdc42 protein levels, and the in vitro fertilization (IVF). After the treatment, the blood Pb (PbB) concentration was 9.4 ± 1.6 μg/dL. Abnormal sperm morphology and the oAR increased (8 and 19%, respectively), whereas the iAR decreased (15%) after a calcium ionophore challenge, and the actin polymerization decreased in the sperm heads (59%) and tails (42%). Rac1 was the only Rho protein to significantly decrease (33%). Spermatozoa from the Pb-treated mice showed a significant reduction in the fertilization rate (19%). Our data suggest that Pb exposure at environmental concentrations (PbB < 10 μg/dL) decreases the acrosome function and affects the sperm fertilization ability; this is probably a consequence of the low Rac1 levels, which did not allow adequate actin polymerization to occur.
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11
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López Tobón A, Suresh M, Jin J, Vitriolo A, Pietralla T, Tedford K, Bossenz M, Mahnken K, Kiefer F, Testa G, Fischer KD, Püschel AW. The guanine nucleotide exchange factor Arhgef7/βPix promotes axon formation upstream of TC10. Sci Rep 2018; 8:8811. [PMID: 29891904 PMCID: PMC5995858 DOI: 10.1038/s41598-018-27081-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/29/2018] [Indexed: 11/10/2022] Open
Abstract
The characteristic six layers of the mammalian neocortex develop sequentially as neurons are generated by neural progenitors and subsequently migrate past older neurons to their final position in the cortical plate. One of the earliest steps of neuronal differentiation is the formation of an axon. Small GTPases play essential roles during this process by regulating cytoskeletal dynamics and intracellular trafficking. While the function of GTPases has been studied extensively in cultured neurons and in vivo much less is known about their upstream regulators. Here we show that Arhgef7 (also called βPix or Cool1) is essential for axon formation during cortical development. The loss of Arhgef7 results in an extensive loss of axons in cultured neurons and in the developing cortex. Arhgef7 is a guanine-nucleotide exchange factor (GEF) for Cdc42, a GTPase that has a central role in directing the formation of axons during brain development. However, active Cdc42 was not able to rescue the knockdown of Arhgef7. We show that Arhgef7 interacts with the GTPase TC10 that is closely related to Cdc42. Expression of active TC10 can restore the ability to extend axons in Arhgef7-deficient neurons. Our results identify an essential role of Arhgef7 during neuronal development that promotes axon formation upstream of TC10.
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Affiliation(s)
- Alejandro López Tobón
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany.,Department of Oncology and Hemato-Oncology, University of Milan, Milan, 20122, Italy.,European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Megalakshmi Suresh
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany
| | - Jing Jin
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany
| | - Alessandro Vitriolo
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, 20122, Italy.,European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Thorben Pietralla
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany
| | - Kerry Tedford
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Leipziger Str. 44, 39120, Magdeburg, 39120, Germany
| | - Michael Bossenz
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Leipziger Str. 44, 39120, Magdeburg, 39120, Germany
| | - Kristina Mahnken
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany
| | - Friedemann Kiefer
- Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany.,Max-Planck-Institute for Molecular Biomedicine, Mammalian cell signaling laboratory, Röntgenstr. 20, D-48149, Münster, Germany.,European Institute for Molecular Imaging, Westfälische Wilhelms-Universität, Waldeyerstr. 15, D-48149, Münster, Germany
| | - Giuseppe Testa
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, 20122, Italy.,European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Klaus-Dieter Fischer
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Leipziger Str. 44, 39120, Magdeburg, 39120, Germany
| | - Andreas W Püschel
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany. .,Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany.
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12
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Gasman S, Vitale N. Lipid remodelling in neuroendocrine secretion. Biol Cell 2017; 109:381-390. [DOI: 10.1111/boc.201700030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Stéphane Gasman
- Institut des Neurosciences Cellulaires et Intégratives; CNRS UPR3212; Université de Strasbourg; Strasbourg France
- INSERM; Paris Cedex 75654 France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives; CNRS UPR3212; Université de Strasbourg; Strasbourg France
- INSERM; Paris Cedex 75654 France
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13
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Zhou W, Li X, Premont RT. Expanding functions of GIT Arf GTPase-activating proteins, PIX Rho guanine nucleotide exchange factors and GIT-PIX complexes. J Cell Sci 2017; 129:1963-74. [PMID: 27182061 DOI: 10.1242/jcs.179465] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The GIT proteins, GIT1 and GIT2, are GTPase-activating proteins (inactivators) for the ADP-ribosylation factor (Arf) small GTP-binding proteins, and function to limit the activity of Arf proteins. The PIX proteins, α-PIX and β-PIX (also known as ARHGEF6 and ARHGEF7, respectively), are guanine nucleotide exchange factors (activators) for the Rho family small GTP-binding protein family members Rac1 and Cdc42. Through their multi-domain structures, GIT and PIX proteins can also function as signaling scaffolds by binding to numerous protein partners. Importantly, the constitutive association of GIT and PIX proteins into oligomeric GIT-PIX complexes allows these two proteins to function together as subunits of a larger structure that coordinates two distinct small GTP-binding protein pathways and serves as multivalent scaffold for the partners of both constituent subunits. Studies have revealed the involvement of GIT and PIX proteins, and of the GIT-PIX complex, in numerous fundamental cellular processes through a wide variety of mechanisms, pathways and signaling partners. In this Commentary, we discuss recent findings in key physiological systems that exemplify current understanding of the function of this important regulatory complex. Further, we draw attention to gaps in crucial information that remain to be filled to allow a better understanding of the many roles of the GIT-PIX complex in health and disease.
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Affiliation(s)
- Wu Zhou
- Department of Medicine, College of Medicine and Health, Lishui University, Lishui 323000, China
| | - Xiaobo Li
- Department of Computer Science and Technology, College of Engineering and Design, Lishui University, Lishui 323000, China
| | - Richard T Premont
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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14
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González-Jamett AM, Guerra MJ, Olivares MJ, Haro-Acuña V, Baéz-Matus X, Vásquez-Navarrete J, Momboisse F, Martinez-Quiles N, Cárdenas AM. The F-Actin Binding Protein Cortactin Regulates the Dynamics of the Exocytotic Fusion Pore through its SH3 Domain. Front Cell Neurosci 2017; 11:130. [PMID: 28522963 PMCID: PMC5415606 DOI: 10.3389/fncel.2017.00130] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 04/18/2017] [Indexed: 11/20/2022] Open
Abstract
Upon cell stimulation, the network of cortical actin filaments is rearranged to facilitate the neurosecretory process. This actin rearrangement includes both disruption of the preexisting actin network and de novo actin polymerization. However, the mechanism by which a Ca2+ signal elicits the formation of new actin filaments remains uncertain. Cortactin, an actin-binding protein that promotes actin polymerization in synergy with the nucleation promoting factor N-WASP, could play a key role in this mechanism. We addressed this hypothesis by analyzing de novo actin polymerization and exocytosis in bovine adrenal chromaffin cells expressing different cortactin or N-WASP domains, or cortactin mutants that fail to interact with proline-rich domain (PRD)-containing proteins, including N-WASP, or to be phosphorylated by Ca2+-dependent kinases, such as ERK1/2 and Src. Our results show that the activation of nicotinic receptors in chromaffin cells promotes cortactin translocation to the cell cortex, where it colocalizes with actin filaments. We further found that, in association with PRD-containing proteins, cortactin contributes to the Ca2+-dependent formation of F-actin, and regulates fusion pore dynamics and the number of exocytotic events induced by activation of nicotinic receptors. However, whereas the actions of cortactin on the fusion pore dynamics seems to depend on the availability of monomeric actin and its phosphorylation by ERK1/2 and Src kinases, cortactin regulates the extent of exocytosis by a mechanism independent of actin polymerization. Together our findings point out a role for cortactin as a critical modulator of actin filament formation and exocytosis in neuroendocrine cells.
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Affiliation(s)
- Arlek M González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
| | - María J Guerra
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
| | - María J Olivares
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
| | - Valentina Haro-Acuña
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
| | - Ximena Baéz-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
| | - Jacqueline Vásquez-Navarrete
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
| | - Fanny Momboisse
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
| | - Narcisa Martinez-Quiles
- Departamento de Microbiología (Inmunología), Facultad de Medicina, Universidad Complutense de MadridMadrid, Spain
| | - Ana M Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
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15
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Sun T, Yang L, Kaur H, Pestel J, Looso M, Nolte H, Krasel C, Heil D, Krishnan RK, Santoni MJ, Borg JP, Bünemann M, Offermanns S, Swiercz JM, Worzfeld T. A reverse signaling pathway downstream of Sema4A controls cell migration via Scrib. J Cell Biol 2016; 216:199-215. [PMID: 28007914 PMCID: PMC5223600 DOI: 10.1083/jcb.201602002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 09/30/2016] [Accepted: 11/13/2016] [Indexed: 11/22/2022] Open
Abstract
Semaphorins comprise a large family of ligands that regulate key cellular functions through their receptors, plexins. In this study, we show that the transmembrane semaphorin 4A (Sema4A) can also function as a receptor, rather than a ligand, and transduce signals triggered by the binding of Plexin-B1 through reverse signaling. Functionally, reverse Sema4A signaling regulates the migration of various cancer cells as well as dendritic cells. By combining mass spectrometry analysis with small interfering RNA screening, we identify the polarity protein Scrib as a downstream effector of Sema4A. We further show that binding of Plexin-B1 to Sema4A promotes the interaction of Sema4A with Scrib, thereby removing Scrib from its complex with the Rac/Cdc42 exchange factor βPIX and decreasing the activity of the small guanosine triphosphatase Rac1 and Cdc42. Our data unravel a role for Plexin-B1 as a ligand and Sema4A as a receptor and characterize a reverse signaling pathway downstream of Sema4A, which controls cell migration.
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Affiliation(s)
- Tianliang Sun
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Lida Yang
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Harmandeep Kaur
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Jenny Pestel
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Mario Looso
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Hendrik Nolte
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Cornelius Krasel
- Institute of Pharmacology and Clinical Pharmacy, Biochemical-Pharmacological Center, University of Marburg, 35043 Marburg, Germany
| | - Daniel Heil
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Ramesh K Krishnan
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Marie-Josée Santoni
- Cell Polarity, Cell Signaling and Cancer, Equipe labellisée Ligue Contre le Cancer, Institut National de la Santé et de la Recherche Médicale, U1068, 13009 Marseille, France.,Institut Paoli-Calmettes, 13009 Marseille, France.,Aix-Marseille Université, 13284 Marseille, France.,Centre National de la Recherche Scientifique, UMR7258, 13273 Marseille, France
| | - Jean-Paul Borg
- Cell Polarity, Cell Signaling and Cancer, Equipe labellisée Ligue Contre le Cancer, Institut National de la Santé et de la Recherche Médicale, U1068, 13009 Marseille, France.,Institut Paoli-Calmettes, 13009 Marseille, France.,Aix-Marseille Université, 13284 Marseille, France.,Centre National de la Recherche Scientifique, UMR7258, 13273 Marseille, France
| | - Moritz Bünemann
- Institute of Pharmacology and Clinical Pharmacy, Biochemical-Pharmacological Center, University of Marburg, 35043 Marburg, Germany
| | - Stefan Offermanns
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.,Medical Faculty, University of Frankfurt, 60590 Frankfurt am Main, Germany
| | - Jakub M Swiercz
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Thomas Worzfeld
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany .,Institute of Pharmacology, Biochemical-Pharmacological Center, University of Marburg, 35043 Marburg, Germany
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16
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Song HI, Yoon MS. PLD1 regulates adipogenic differentiation through mTOR - IRS-1 phosphorylation at serine 636/639. Sci Rep 2016; 6:36968. [PMID: 27872488 PMCID: PMC5181839 DOI: 10.1038/srep36968] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/24/2016] [Indexed: 01/08/2023] Open
Abstract
Phospholipase D1 (PLD1) plays a known role in several differentiation processes, but its role in adipogenic differentiation remains unknown. In the present study, we identified PLD1 as a negative regulator of adipogenic differentiation. We showed that PLD activity was downregulated by both 3-Isobutyl-1-methylxanthine (IBMX) and insulin upon induction of differentiation in 3T3-L1 adipogenic cells. In line with this observation, PLD activity decreased in both high fat diet (HFD)-fed mice and ob/ob mice. We also found that differentiation of 3T3-L1 preadipocytes was enhanced by the depletion of PLD1 levels or inhibition of PLD1 activity by VU0155069, a PLD1-specific inhibitor. Conversely, treatment with phosphatidic acid (PA), a PLD product, and overexpression of PLD1 both caused a decrease in adipogenic differentiation. Moreover, the elevated differentiation in PLD1-knockdown 3T3-L1 cells was reduced by either PA treatment or PLD1 expression, confirming negative roles of PLD1 and PA in adipogenic differentiation. Further investigation revealed that PA displaces DEP domain-containing mTOR-interacting protein (DEPTOR) from mTORC1, which subsequently phosphorylates insulin receptor substrate-1 (IRS-1) at serine 636/639 in 3T3-L1 cells. Taken together, our findings provide convincing evidence for a direct role of PLD1 in adipogenic differentiation by regulating IRS-1 phosphorylation at serine 636/639 through DEPTOR displacement and mTOR activation.
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Affiliation(s)
- Hae-In Song
- Department of Molecular Medicine, School of Medicine, Gachon University, Incheon 406-840, Republic of Korea
| | - Mee-Sup Yoon
- Department of Molecular Medicine, School of Medicine, Gachon University, Incheon 406-840, Republic of Korea
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17
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Phosphorylated and Nonphosphorylated PfMAP2 Are Localized in the Nucleus, Dependent on the Stage of Plasmodium falciparum Asexual Maturation. BIOMED RESEARCH INTERNATIONAL 2016; 2016:1645097. [PMID: 27525262 PMCID: PMC4976173 DOI: 10.1155/2016/1645097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/16/2016] [Indexed: 11/30/2022]
Abstract
Plasmodium falciparum mitogen-activated protein (MAP) kinases, a family of enzymes central to signal transduction processes including inflammatory responses, are a promising target for antimalarial drug development. Our study shows for the first time that the P. falciparum specific MAP kinase 2 (PfMAP2) is colocalized in the nucleus of all of the asexual erythrocytic stages of P. falciparum and is particularly elevated in its phosphorylated form. It was also discovered that PfMAP2 is expressed in its highest quantity during the early trophozoite (ring form) stage and significantly reduced in the mature trophozoite and schizont stages. Although the phosphorylated form of the kinase is always more prevalent, its ratio relative to the nonphosphorylated form remained constant irrespective of the parasites' developmental stage. We have also shown that the TSH motif specifically renders PfMAP2 genetically divergent from the other plasmodial MAP kinase activation sites using Neighbour Joining analysis. Furthermore, TSH motif-specific designed antibody is crucial in determining the location of the expression of the PfMAP2 protein. However, by using immunoelectron microscopy, PPfMAP2 were detected ubiquitously in the parasitized erythrocytes. In summary, PfMAP2 may play a far more important role than previously thought and is a worthy candidate for research as an antimalarial.
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18
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Oligophrenin-1 Connects Exocytotic Fusion to Compensatory Endocytosis in Neuroendocrine Cells. J Neurosci 2015; 35:11045-55. [PMID: 26245966 DOI: 10.1523/jneurosci.4048-14.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Oligophrenin-1 (OPHN1) is a protein with multiple domains including a Rho family GTPase-activating (Rho-GAP) domain, and a Bin-Amphiphysin-Rvs (BAR) domain. Involved in X-linked intellectual disability, OPHN1 has been reported to control several synaptic functions, including synaptic plasticity, synaptic vesicle trafficking, and endocytosis. In neuroendocrine cells, hormones and neuropeptides stored in large dense core vesicles (secretory granules) are released through calcium-regulated exocytosis, a process that is tightly coupled to compensatory endocytosis, allowing secretory granule recycling. We show here that OPHN1 is expressed and mainly localized at the plasma membrane and in the cytosol in chromaffin cells from adrenal medulla. Using carbon fiber amperometry, we found that exocytosis is impaired at the late stage of membrane fusion in Ophn1 knock-out mice and OPHN1-silenced bovine chromaffin cells. Experiments performed with ectopically expressed OPHN1 mutants indicate that OPHN1 requires its Rho-GAP domain to control fusion pore dynamics. On the other hand, compensatory endocytosis assessed by measuring dopamine-β-hydroxylase (secretory granule membrane) internalization is severely inhibited in Ophn1 knock-out chromaffin cells. This inhibitory effect is mimicked by the expression of a truncated OPHN1 mutant lacking the BAR domain, demonstrating that the BAR domain implicates OPHN1 in granule membrane recapture after exocytosis. These findings reveal for the first time that OPHN1 is a bifunctional protein that is able, through distinct mechanisms, to regulate and most likely link exocytosis to compensatory endocytosis in chromaffin cells.
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19
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Jaudon F, Raynaud F, Wehrlé R, Bellanger JM, Doulazmi M, Vodjdani G, Gasman S, Fagni L, Dusart I, Debant A, Schmidt S. The RhoGEF DOCK10 is essential for dendritic spine morphogenesis. Mol Biol Cell 2015; 26:2112-27. [PMID: 25851601 PMCID: PMC4472020 DOI: 10.1091/mbc.e14-08-1310] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 04/02/2015] [Indexed: 12/15/2022] Open
Abstract
By regulating actin cytoskeleton dynamics, Rho GTPases and their activators RhoGEFs are implicated in various aspects of neuronal differentiation, including dendritogenesis and synaptogenesis. Purkinje cells (PCs) of the cerebellum, by developing spectacular dendrites covered with spines, represent an attractive model system in which to decipher the molecular signaling underlying these processes. To identify novel regulators of dendritic spine morphogenesis among members of the poorly characterized DOCK family of RhoGEFs, we performed gene expression profiling of fluorescence-activated cell sorting (FACS)-purified murine PCs at various stages of their postnatal differentiation. We found a strong increase in the expression of the Cdc42-specific GEF DOCK10. Depleting DOCK10 in organotypic cerebellar cultures resulted in dramatic dendritic spine defects in PCs. Accordingly, in mouse hippocampal neurons, depletion of DOCK10 or expression of a DOCK10 GEF-dead mutant led to a strong decrease in spine density and size. Conversely, overexpression of DOCK10 led to increased spine formation. We show that DOCK10 function in spinogenesis is mediated mainly by Cdc42 and its downstream effectors N-WASP and PAK3, although DOCK10 is also able to activate Rac1. Our global approach thus identifies an unprecedented function for DOCK10 as a novel regulator of dendritic spine morphogenesis via a Cdc42-mediated pathway.
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Affiliation(s)
- Fanny Jaudon
- Centre de Recherche en Biochimie Macromoléculaire, CNRS-UMR 5237, Université de Montpellier, 34293 Montpellier, France
| | - Fabrice Raynaud
- Institute of Functional Genomics, CNRS-UMR 5203, INSERM U661, Université de Montpellier, 34094 Montpellier, France
| | - Rosine Wehrlé
- Université Pierre et Marie Curie, CNRS-UMR 7102, Université Paris 06, 75005 Paris, France
| | - Jean-Michel Bellanger
- Centre de Recherche en Biochimie Macromoléculaire, CNRS-UMR 5237, Université de Montpellier, 34293 Montpellier, France
| | - Mohamed Doulazmi
- Université Pierre et Marie Curie, CNRS-UMR 7102, Université Paris 06, 75005 Paris, France
| | - Guilan Vodjdani
- PROTECT, Neuroprotection du cerveau en développement, UMR1141-INSERM, Université Paris-Diderot, Sorbonne Paris-Cité, 75019 Paris, France
| | - Stéphane Gasman
- Institut des Neurosciences Cellulaires et Intégratives, CNRS-UPR 3212, Centre de Neurochimie, Université de Strasbourg, 67084 Strasbourg, France
| | - Laurent Fagni
- Institute of Functional Genomics, CNRS-UMR 5203, INSERM U661, Université de Montpellier, 34094 Montpellier, France
| | - Isabelle Dusart
- Université Pierre et Marie Curie, CNRS-UMR 7102, Université Paris 06, 75005 Paris, France
| | - Anne Debant
- Centre de Recherche en Biochimie Macromoléculaire, CNRS-UMR 5237, Université de Montpellier, 34293 Montpellier, France
| | - Susanne Schmidt
- Centre de Recherche en Biochimie Macromoléculaire, CNRS-UMR 5237, Université de Montpellier, 34293 Montpellier, France
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20
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The role of Pak-interacting exchange factor-β phosphorylation at serines 340 and 583 by PKCγ in dopamine release. J Neurosci 2014; 34:9268-80. [PMID: 25009260 DOI: 10.1523/jneurosci.4278-13.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Protein kinase C (PKC) has been implicated in the control of neurotransmitter release. The AS/AGU rat, which has a nonsense mutation in PKCγ, shows symptoms of parkinsonian syndrome, including dopamine release impairments in the striatum. Here, we found that the AS/AGU rat is PKCγ-knock-out (KO) and that PKCγ-KO mice showed parkinsonian syndrome. However, the PKCγ substrates responsible for the regulated exocytosis of dopamine in vivo have not yet been elucidated. To identify the PKCγ substrates involved in dopamine release, we used PKCγ-KO mice and a phosphoproteome analysis. We found 10 candidate phosphoproteins that had decreased phosphorylation levels in the striatum of PKCγ-KO mice. We focused on Pak-interacting exchange factor-β (βPIX), a Cdc42/Rac1 guanine nucleotide exchange factor, and found that PKCγ directly phosphorylates βPIX at Ser583 and indirectly at Ser340 in cells. Furthermore, we found that PKC phosphorylated βPIX in vivo. Classical PKC inhibitors and βPIX knock-down (KD) significantly suppressed Ca(2+)-evoked dopamine release in PC12 cells. Wild-type βPIX, and not the βPIX mutants Ser340 Ala or Ser583 Ala, fully rescued the decreased dopamine release by βPIX KD. Double KD of Cdc42 and Rac1 decreased dopamine release from PC12 cells. These findings indicate that the phosphorylation of βPIX at Ser340 and Ser583 has pivotal roles in Ca(2+)-evoked dopamine release in the striatum. Therefore, we propose that PKCγ positively modulates dopamine release through β2PIX phosphorylation. The PKCγ-βPIX-Cdc42/Rac1 phosphorylation axis may provide a new therapeutic target for the treatment of parkinsonian syndrome.
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21
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Boczonadi V, Gillespie R, Keenan I, Ramsbottom SA, Donald-Wilson C, Al Nazer M, Humbert P, Schwarz RJ, Chaudhry B, Henderson DJ. Scrib:Rac1 interactions are required for the morphogenesis of the ventricular myocardium. Cardiovasc Res 2014; 104:103-15. [PMID: 25139745 PMCID: PMC4174891 DOI: 10.1093/cvr/cvu193] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Aims The organization and maturation of ventricular cardiomyocytes from the embryonic to the adult form is crucial for normal cardiac function. We have shown that a polarity protein, Scrib, may be involved in regulating the early stages of this process. Our goal was to establish whether Scrib plays a cell autonomous role in the ventricular myocardium, and whether this involves well-known polarity pathways. Methods and results Deletion of Scrib in cardiac precursors utilizing Scribflox mice together with the Nkx2.5-Cre driver resulted in disruption of the cytoarchitecture of the forming trabeculae and ventricular septal defects. Although the majority of mice lacking Scrib in the myocardium survived to adulthood, they developed marked cardiac fibrosis. Scrib did not physically interact with the planar cell polarity (PCP) protein, Vangl2, in early cardiomyocytes as it does in other tissues, suggesting that the anomalies did not result from disruption of PCP signalling. However, Scrib interacted with Rac1 physically in embryonic cardiomyocytes and genetically to result in ventricular abnormalities, suggesting that this interaction is crucial for the development of the early myocardium. Conclusions The Scrib–Rac1 interaction plays a crucial role in the organization of developing cardiomyocytes and formation of the ventricular myocardium. Thus, we have identified a novel signalling pathway in the early, functioning, heart muscle. These data also show that the foetus can recover from relatively severe abnormalities in prenatal ventricular development, although cardiac fibrosis can be a long-term consequence.
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Affiliation(s)
- Veronika Boczonadi
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Rachel Gillespie
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Iain Keenan
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Simon A Ramsbottom
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | | | - Mariana Al Nazer
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Patrick Humbert
- Cell Cycle and Cancer Genetics Laboratory, Peter MacCallum Cancer Centre, East Melbourne, Australia Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Melbourne, Australia Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Melbourne, Australia Department of Pathology, University of Melbourne, Parkville, Melbourne, Australia
| | | | - Bill Chaudhry
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Deborah J Henderson
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
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22
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Croisé P, Estay-Ahumada C, Gasman S, Ory S. Rho GTPases, phosphoinositides, and actin: a tripartite framework for efficient vesicular trafficking. Small GTPases 2014; 5:e29469. [PMID: 24914539 DOI: 10.4161/sgtp.29469] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Rho GTPases are well known regulators of the actin cytoskeleton that act by binding and activating actin nucleators. They are therefore involved in many actin-based processes, including cell migration, cell polarity, and membrane trafficking. With the identification of phosphoinositide kinases and phosphatases as potential binding partners or effectors, Rho GTPases also appear to participate in the regulation of phosphoinositide metabolism. Since both actin dynamics and phosphoinositide turnover affect the efficiency and the fidelity of vesicle transport between cell compartments, Rho GTPases have emerged as critical players in membrane trafficking. Rho GTPase activity, actin remodeling, and phosphoinositide metabolism need to be coordinated in both space and time to ensure the progression of vesicles along membrane trafficking pathways. Although most molecular pathways are still unclear, in this review, we will highlight recent advances made in our understanding of how Rho-dependent signaling pathways organize actin dynamics and phosphoinositides and how phosphoinositides potentially provide negative feedback to Rho GTPases during endocytosis, exocytosis and membrane exchange between intracellular compartments.
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Affiliation(s)
- Pauline Croisé
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Catherine Estay-Ahumada
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Stéphane Gasman
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Stéphane Ory
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
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23
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Raynaud F, Moutin E, Schmidt S, Dahl J, Bertaso F, Boeckers TM, Homburger V, Fagni L. Rho-GTPase-activating protein interacting with Cdc-42-interacting protein 4 homolog 2 (Rich2): a new Ras-related C3 botulinum toxin substrate 1 (Rac1) GTPase-activating protein that controls dendritic spine morphogenesis. J Biol Chem 2013; 289:2600-9. [PMID: 24352656 DOI: 10.1074/jbc.m113.534636] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Development of dendritic spines is important for synaptic function, and alteration in spine morphogenesis is often associated with mental disorders. Rich2 was an uncharacterized Rho-GAP protein. Here we searched for a role of this protein in spine morphogenesis. We found that it is enriched in dendritic spines of cultured hippocampal pyramidal neurons during early stages of development. Rich2 specifically stimulated the Rac1 GTPase in these neurons. Inhibition of Rac1 by EHT 1864 increased the size and decreased the density of dendritic spines. Similarly, Rich2 overexpression increased the size and decreased the density of dendritic spines, whereas knock-down of the protein by specific si-RNA decreased both size and density of spines. The morphological changes were reflected by the increased amplitude and decreased frequency of miniature EPSCs induced by Rich2 overexpression, while si-RNA treatment decreased both amplitude and frequency of these events. Finally, treatment of neurons with EHT 1864 rescued the phenotype induced by Rich2 knock-down. These results suggested that Rich2 controls dendritic spine morphogenesis and function via inhibition of Rac1.
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Affiliation(s)
- Fabrice Raynaud
- From CNRS, UMR-5203, Institut de Génomique Fonctionnelle, F-34000 Montpellier, France
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González-Jamett AM, Momboisse F, Guerra MJ, Ory S, Báez-Matus X, Barraza N, Calco V, Houy S, Couve E, Neely A, Martínez AD, Gasman S, Cárdenas AM. Dynamin-2 regulates fusion pore expansion and quantal release through a mechanism that involves actin dynamics in neuroendocrine chromaffin cells. PLoS One 2013; 8:e70638. [PMID: 23940613 PMCID: PMC3734226 DOI: 10.1371/journal.pone.0070638] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 06/25/2013] [Indexed: 11/29/2022] Open
Abstract
Over the past years, dynamin has been implicated in tuning the amount and nature of transmitter released during exocytosis. However, the mechanism involved remains poorly understood. Here, using bovine adrenal chromaffin cells, we investigated whether this mechanism rely on dynamin’s ability to remodel actin cytoskeleton. According to this idea, inhibition of dynamin GTPase activity suppressed the calcium-dependent de novo cortical actin and altered the cortical actin network. Similarly, expression of a small interfering RNA directed against dynamin-2, an isoform highly expressed in chromaffin cells, changed the cortical actin network pattern. Disruption of dynamin-2 function, as well as the pharmacological inhibition of actin polymerization with cytochalasine-D, slowed down fusion pore expansion and increased the quantal size of individual exocytotic events. The effects of cytochalasine-D and dynamin-2 disruption were not additive indicating that dynamin-2 and F-actin regulate the late steps of exocytosis by a common mechanism. Together our data support a model in which dynamin-2 directs actin polymerization at the exocytosis site where both, in concert, adjust the hormone quantal release to efficiently respond to physiological demands.
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Affiliation(s)
- Arlek M. González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
| | - Fanny Momboisse
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique (CNRS UPR 3212), and Université de Strasbourg, Strasbourg, France
| | - María José Guerra
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
| | - Stéphane Ory
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique (CNRS UPR 3212), and Université de Strasbourg, Strasbourg, France
| | - Ximena Báez-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
| | - Natalia Barraza
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
| | - Valerie Calco
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique (CNRS UPR 3212), and Université de Strasbourg, Strasbourg, France
| | - Sébastien Houy
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique (CNRS UPR 3212), and Université de Strasbourg, Strasbourg, France
| | - Eduardo Couve
- Departamento de Biololgía, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
| | - Alan Neely
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
| | - Stéphane Gasman
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique (CNRS UPR 3212), and Université de Strasbourg, Strasbourg, France
- * E-mail: (AMC); (SG)
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña, Playa Ancha, Valparaíso, Chile
- * E-mail: (AMC); (SG)
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Sabirzhanova I, Liu C, Zhao J, Bramlett H, Dietrich WD, Hu B. Changes in the GEF-H1 pathways after traumatic brain injury. J Neurotrauma 2013; 30:1449-56. [PMID: 23611588 DOI: 10.1089/neu.2012.2673] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Brains undergo significant remodeling after traumatic brain injury (TBI). The Rho guanine triphosphate (GTP)ase pathways control brain remodeling during development and under pathological conditions. How the Rho GTPase pathways are regulated in the brain after TBI remains largely unknown, however. This study used the rat fluid percussion injury model to investigate changes in the Rho GTPase pathways after TBI. The results showed that TBI leads to activation and translocation of RhoA and Rac1 proteins from cytosolic fraction to the membrane fraction after injury. Consistently, the Rho guanine nucleotide exchange factors GEF-H1 and Cool-2/αPix are significantly activated by dephosphorylation and accumulation in the cytosolic fractions during the post-TBI phase. Because the Rho GTPase pathways are key regulators of brain remodeling, these results depict regulatory mechanisms of the Rho GTPase pathways after TBI, and pave the way for the study of therapeutic agents targeting the Rho GTPase pathways for functional recovery after TBI.
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Affiliation(s)
- Inna Sabirzhanova
- Neurochemistry Laboratory of Brain Injury, Department of Anesthesiology, and Shock Trauma and Anesthesiology Research Center, University of Maryland School of Medicine , Baltimore, MD 21201, USA
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Phospholipid scramblase-1-induced lipid reorganization regulates compensatory endocytosis in neuroendocrine cells. J Neurosci 2013; 33:3545-56. [PMID: 23426682 DOI: 10.1523/jneurosci.3654-12.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Calcium-regulated exocytosis in neuroendocrine cells and neurons is accompanied by the redistribution of phosphatidylserine (PS) to the extracellular space, leading to a disruption of plasma membrane asymmetry. How and why outward translocation of PS occurs during secretion are currently unknown. Immunogold labeling on plasma membrane sheets coupled with hierarchical clustering analysis demonstrate that PS translocation occurs at the vicinity of the secretory granule fusion sites. We found that altering the function of the phospholipid scramblase-1 (PLSCR-1) by expressing a PLSCR-1 calcium-insensitive mutant or by using chromaffin cells from PLSCR-1⁻/⁻ mice prevents outward translocation of PS in cells stimulated for exocytosis. Remarkably, whereas transmitter release was not affected, secretory granule membrane recapture after exocytosis was impaired, indicating that PLSCR-1 is required for compensatory endocytosis but not for exocytosis. Our results provide the first evidence for a role of specific lipid reorganization and calcium-dependent PLSCR-1 activity in neuroendocrine compensatory endocytosis.
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Chi X, Wang S, Huang Y, Stamnes M, Chen JL. Roles of rho GTPases in intracellular transport and cellular transformation. Int J Mol Sci 2013; 14:7089-108. [PMID: 23538840 PMCID: PMC3645678 DOI: 10.3390/ijms14047089] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 03/04/2013] [Accepted: 03/12/2013] [Indexed: 01/21/2023] Open
Abstract
Rho family GTPases belong to the Ras GTPase superfamily and transduce intracellular signals known to regulate a variety of cellular processes, including cell polarity, morphogenesis, migration, apoptosis, vesicle trafficking, viral transport and cellular transformation. The three best-characterized Rho family members are Cdc42, RhoA and Rac1. Cdc42 regulates endocytosis, the transport between the endoplasmic reticulum and Golgi apparatus, post-Golgi transport and exocytosis. Cdc42 influences trafficking through interaction with Wiskott-Aldrich syndrome protein (N-WASP) and the Arp2/3 complex, leading to changes in actin dynamics. Rac1 mediates endocytic and exocytic vesicle trafficking by interaction with its effectors, PI3kinase, synaptojanin 2, IQGAP1 and phospholipase D1. RhoA participates in the regulation of endocytosis through controlling its downstream target, Rho kinase. Interestingly, these GTPases play important roles at different stages of viral protein and genome transport in infected host cells. Importantly, dysregulation of Cdc42, Rac1 and RhoA leads to numerous disorders, including malignant transformation. In some cases, hyperactivation of Rho GTPases is required for cellular transformation. In this article, we review a number of findings related to Rho GTPase function in intracellular transport and cellular transformation.
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Affiliation(s)
- Xiaojuan Chi
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; E-Mails: (X.C.); (Y.H.)
| | - Song Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China; E-Mail:
| | - Yifan Huang
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; E-Mails: (X.C.); (Y.H.)
| | - Mark Stamnes
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA; E-Mail:
| | - Ji-Long Chen
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; E-Mails: (X.C.); (Y.H.)
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +86-10-6480-7300; Fax: +86-10-6480-7980
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28
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Totaro A, Tavano S, Filosa G, Gärtner A, Pennucci R, Santambrogio P, Bachi A, Dotti CG, de Curtis I. Biochemical and functional characterisation of αPIX, a specific regulator of axonal and dendritic branching in hippocampal neurons. Biol Cell 2012; 104:533-52. [DOI: 10.1111/boc.201100060] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 04/24/2012] [Indexed: 01/13/2023]
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29
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The Golgi-associated long coiled-coil protein NECC1 participates in the control of the regulated secretory pathway in PC12 cells. Biochem J 2012; 443:387-96. [PMID: 22250954 DOI: 10.1042/bj20110554] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Golgi-associated long coiled-coil proteins, often referred to as golgins, are involved in the maintenance of the structural organization of the Golgi apparatus and the regulation of membrane traffic events occurring in this organelle. Little information is available on the contribution of golgins to Golgi function in cells specialized in secretion such as endocrine cells or neurons. In the present study, we characterize the intracellular distribution as well as the biochemical and functional properties of a novel long coiled-coil protein present in neuroendocrine tissues, NECC1 (neuroendocrine long coiled-coil protein 1). The present study shows that NECC1 is a peripheral membrane protein displaying high stability to detergent extraction, which distributes across the Golgi apparatus in neuroendocrine cells. In addition, NECC1 partially localizes to post-Golgi carriers containing secretory cargo in PC12 cells. Overexpression of NECC1 resulted in the formation of juxtanuclear aggregates together with a slight fragmentation of the Golgi and a decrease in K+-stimulated hormone release. In contrast, NECC1 silencing did not alter Golgi architecture, but enhanced K+-stimulated hormone secretion in PC12 cells. In all, the results of the present study identify NECC1 as a novel component of the Golgi matrix and support a role for this protein as a negative modulator of the regulated trafficking of secretory cargo in neuroendocrine cells.
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30
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Kolesnikov YS, Nokhrina KP, Kretynin SV, Volotovski ID, Martinec J, Romanov GA, Kravets VS. Molecular structure of phospholipase D and regulatory mechanisms of its activity in plant and animal cells. BIOCHEMISTRY (MOSCOW) 2012; 77:1-14. [DOI: 10.1134/s0006297912010014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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de Curtis I, Meldolesi J. Cell surface dynamics – how Rho GTPases orchestrate the interplay between the plasma membrane and the cortical cytoskeleton. J Cell Sci 2012; 125:4435-44. [DOI: 10.1242/jcs.108266] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Small GTPases are known to regulate hundreds of cell functions. In particular, Rho family GTPases are master regulators of the cytoskeleton. By regulating actin nucleation complexes, Rho GTPases control changes in cell shape, including the extension and/or retraction of surface protrusions and invaginations. Protrusion and invagination of the plasma membrane also involves the interaction between the plasma membrane and the cortical cytoskeleton. This interplay between membranes and the cytoskeleton can lead to an increase or decrease in the plasma membrane surface area and its tension as a result of the fusion (exocytosis) or internalization (endocytosis) of membranous compartments, respectively. For a long time, the cytoskeleton and plasma membrane dynamics were investigated separately. However, studies from many laboratories have now revealed that Rho GTPases, their modulation of the cytoskeleton, and membrane traffic are closely connected during the dynamic remodeling of the cell surface. Arf- and Rab-dependent exocytosis of specific vesicles contributes to the targeting of Rho GTPases and their regulatory factors to discrete sites of the plasma membrane. Rho GTPases regulate the tethering of exocytic vesicles and modulate their subsequent fusion. They also have crucial roles in the different forms of endocytosis, where they participate in the sorting of membrane domains as well as the sculpting and sealing of membrane flasks and cups. Here, we discuss how cell surface dynamics depend on the orchestration of the cytoskeleton and the plasma membrane by Rho GTPases.
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32
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Kassas N, Tryoen-Tóth P, Corrotte M, Thahouly T, Bader MF, Grant NJ, Vitale N. Genetically encoded probes for phosphatidic acid. Methods Cell Biol 2012; 108:445-59. [PMID: 22325614 DOI: 10.1016/b978-0-12-386487-1.00020-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
In addition to forming bilayers to separate cellular compartments, lipids participate in vesicular trafficking and signal transduction. Among others, phosphatidic acid (PA) is emerging as an important signaling molecule. The spatiotemporal distribution of cellular PA appears to be tightly regulated by localized synthesis and a rapid metabolism. Although PA has been long proposed as a pleiotropic bioactive lipid, when and where PA is produced in the living cells have only recently been explored using biosensors that specifically bind to PA. The probes that we have generated are composed of the PA-binding domains of either Spo20p or Raf1 directly fused to GFP. In this chapter, we will describe the expression and purification of GST-fusion proteins of these probes, and the use of phospholipid strips to validate the specificity of their interaction with PA. We will then illustrate the use of GFP-tagged probes to visualize the synthesis of PA in the neurosecretory PC12 cells and RAW 267.4 macrophages. Interestingly, the two probes show a differential distribution in these cell types, indicating that they may have different affinities for PA or recognize different pools of PA. In conclusion, the development of a broader choice of probes may be required to adequately follow the complex dynamics of PA in different cell types, in order to determine the cellular distribution of PA and its role in various cellular processes.
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Affiliation(s)
- Nawal Kassas
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR3212, Strasbourg, France
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33
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Kepner EM, Yoder SM, Oh E, Kalwat MA, Wang Z, Quilliam LA, Thurmond DC. Cool-1/βPIX functions as a guanine nucleotide exchange factor in the cycling of Cdc42 to regulate insulin secretion. Am J Physiol Endocrinol Metab 2011; 301:E1072-80. [PMID: 21828338 PMCID: PMC3233779 DOI: 10.1152/ajpendo.00312.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Second-phase insulin release requires the sustained mobilization of insulin granules from internal storage pools to the cell surface for fusion with the plasma membrane. However, the detailed mechanisms underlying this process remain largely unknown. GTP-loading of the small GTPase Cdc42 is the first glucose-specific activation step in the process, although how glucose triggers Cdc42 activation is entirely unknown. In a directed candidate screen for guanine nucleotide exchange factors (GEFs), which directly activate small GTPases, Cool-1/βPix was identified in pancreatic islet beta cells. In support of its role as the beta cell Cdc42 GEF, βPix coimmunoprecipitated with Cdc42 in human islets and MIN6 beta cells in a glucose-dependent manner, peaking just prior to Cdc42 activation. Furthermore, RNAi-mediated βPix reduction by 50% corresponded to full ablation of glucose-induced Cdc42 activation and significant attenuation of basal and glucose-stimulated insulin secretion. Of the two Cdc42 guanine nucleotide dissociation inhibitor (GDI) proteins identified in beta cells, βPix competed selectively with caveolin-1 (Cav-1) but not RhoGDI in coimmunoprecipitation and GST-Cdc42-GDP interaction assays. However, a phospho-deficient Cav-1-Y14F mutant failed to compete with βPix; Cav-1(Tyr14) is an established phosphorylation site for Src kinase. Taken together, these data support a new model, wherein glucose stimulates Cav-1 and induces its dissociation from Cdc42, possibly via Src kinase activation to phosphorylate Cav-1(Tyr14), to promote Cdc42-βPix binding and Cdc42 activation, and to trigger downstream signaling and ultimately sustain insulin release.
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Affiliation(s)
- Erica M Kepner
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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34
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Luck K, Fournane S, Kieffer B, Masson M, Nominé Y, Travé G. Putting into practice domain-linear motif interaction predictions for exploration of protein networks. PLoS One 2011; 6:e25376. [PMID: 22069443 PMCID: PMC3206016 DOI: 10.1371/journal.pone.0025376] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 09/02/2011] [Indexed: 12/22/2022] Open
Abstract
PDZ domains recognise short sequence motifs at the extreme C-termini of proteins. A model based on microarray data has been recently published for predicting the binding preferences of PDZ domains to five residue long C-terminal sequences. Here we investigated the potential of this predictor for discovering novel protein interactions that involve PDZ domains. When tested on real negative data assembled from published literature, the predictor displayed a high false positive rate (FPR). We predicted and experimentally validated interactions between four PDZ domains derived from the human proteins MAGI1 and SCRIB and 19 peptides derived from human and viral C-termini of proteins. Measured binding intensities did not correlate with prediction scores, and the high FPR of the predictor was confirmed. Results indicate that limitations of the predictor may arise from an incomplete model definition and improper training of the model. Taking into account these limitations, we identified several novel putative interactions between PDZ domains of MAGI1 and SCRIB and the C-termini of the proteins FZD4, ARHGAP6, NET1, TANC1, GLUT7, MARCH3, MAS, ABC1, DLL1, TMEM215 and CYSLTR2. These proteins are localised to the membrane or suggested to act close to it and are often involved in G protein signalling. Furthermore, we showed that, while extension of minimal interacting domains or peptides toward tandem constructs or longer peptides never suppressed their ability to interact, the measured affinities and inferred specificity patterns often changed significantly. This suggests that if protein fragments interact, the full length proteins are also likely to interact, albeit possibly with altered affinities and specificities. Therefore, predictors dealing with protein fragments are promising tools for discovering protein interaction networks but their application to predict binding preferences within networks may be limited.
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Affiliation(s)
- Katja Luck
- Group Onco-Proteins, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg, 1, BP 10413, Illkirch, France
| | - Sadek Fournane
- Group Onco-Proteins, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg, 1, BP 10413, Illkirch, France
| | - Bruno Kieffer
- Biomolecular NMR group, Institut de Génétique et de Biologie Moléculaire et Cellulaire, 1, BP 10413, Illkirch, France
| | - Murielle Masson
- Group Onco-Proteins, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg, 1, BP 10413, Illkirch, France
| | - Yves Nominé
- Group Onco-Proteins, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg, 1, BP 10413, Illkirch, France
| | - Gilles Travé
- Group Onco-Proteins, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg, 1, BP 10413, Illkirch, France
- * E-mail:
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Rab18 dynamics in adipocytes in relation to lipogenesis, lipolysis and obesity. PLoS One 2011; 6:e22931. [PMID: 21829560 PMCID: PMC3145781 DOI: 10.1371/journal.pone.0022931] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 07/06/2011] [Indexed: 02/03/2023] Open
Abstract
Lipid droplets (LDs) are organelles that coordinate lipid storage and mobilization, both processes being especially important in cells specialized in managing fat, the adipocytes. Proteomic analyses of LDs have consistently identified the small GTPase Rab18 as a component of the LD coat. However, the specific contribution of Rab18 to adipocyte function remains to be elucidated. Herein, we have analyzed Rab18 expression, intracellular localization and function in relation to the metabolic status of adipocytes. We show that Rab18 production increases during adipogenic differentiation of 3T3-L1 cells. In addition, our data show that insulin induces, via phosphatidylinositol 3-kinase (PI3K), the recruitment of Rab18 to the surface of LDs. Furthermore, Rab18 overexpression increased basal lipogenesis and Rab18 silencing impaired the lipogenic response to insulin, thereby suggesting that this GTPase promotes fat accumulation in adipocytes. On the other hand, studies of the β-adrenergic receptor agonist isoproterenol confirmed and extended previous evidence for the participation of Rab18 in lipolysis. Together, our data support the view that Rab18 is a common mediator of lipolysis and lipogenesis and suggests that the endoplasmic reticulum (ER) is the link that enables Rab18 action on these two processes. Finally, we describe, for the first time, the presence of Rab18 in human adipose tissue, wherein the expression of this GTPase exhibits sex- and depot-specific differences and is correlated to obesity. Taken together, these findings indicate that Rab18 is involved in insulin-mediated lipogenesis, as well as in β-adrenergic-induced lipolysis, likely facilitating interaction of LDs with ER membranes and the exchange of lipids between these compartments. A role for Rab18 in the regulation of adipocyte biology under both normal and pathological conditions is proposed.
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36
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Akbar H, Shang X, Perveen R, Berryman M, Funk K, Johnson JF, Tandon NN, Zheng Y. Gene targeting implicates Cdc42 GTPase in GPVI and non-GPVI mediated platelet filopodia formation, secretion and aggregation. PLoS One 2011; 6:e22117. [PMID: 21789221 PMCID: PMC3138762 DOI: 10.1371/journal.pone.0022117] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 06/16/2011] [Indexed: 11/22/2022] Open
Abstract
Background Cdc42 and Rac1, members of the Rho family of small GTPases, play critical roles in actin cytoskeleton regulation. We have shown previously that Rac1 is involved in regulation of platelet secretion and aggregation. However, the role of Cdc42 in platelet activation remains controversial. This study was undertaken to better understand the role of Cdc42 in platelet activation. Methodology/Principal Findings We utilized the Mx-cre;Cdc42lox/lox inducible mice with transient Cdc42 deletion to investigate the involvement of Cdc42 in platelet function. The Cdc42-deficient mice exhibited a significantly reduced platelet count than the matching Cdc42+/+ mice. Platelets isolated from Cdc42−/−, as compared to Cdc42+/+, mice exhibited (a) diminished phosphorylation of PAK1/2, an effector molecule of Cdc42, (b) inhibition of filopodia formation on immobilized CRP or fibrinogen, (c) inhibition of CRP- or thrombin-induced secretion of ATP and release of P-selectin, (d) inhibition of CRP, collagen or thrombin induced platelet aggregation, and (e) minimal phosphorylation of Akt upon stimulation with CRP or thrombin. The bleeding times were significantly prolonged in Cdc42−/− mice compared with Cdc42+/+ mice. Conclusion/Significance Our data demonstrate that Cdc42 is required for platelet filopodia formation, secretion and aggregation and therefore plays a critical role in platelet mediated hemostasis and thrombosis.
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Affiliation(s)
- Huzoor Akbar
- Department of Biomedical Sciences, College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America.
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Peng HJ, Henkels KM, Mahankali M, Marchal C, Bubulya P, Dinauer MC, Gomez-Cambronero J. The dual effect of Rac2 on phospholipase D2 regulation that explains both the onset and termination of chemotaxis. Mol Cell Biol 2011; 31:2227-40. [PMID: 21444720 PMCID: PMC3133238 DOI: 10.1128/mcb.01348-10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 03/15/2011] [Indexed: 01/16/2023] Open
Abstract
We document a biphasic effect of Rac2 on the activation and inhibition of PLD2. Cells overexpressing Rac2 and PLD2 simultaneously show a robust initial (<10 min) response toward a chemoattractant that is later (>30 min) greatly diminished over PLD2-only controls. The first phase is due to the presence of a Rac2-PLD2 positive-feedback loop. To explain the mechanism for the Rac2-led PLD2 inhibition (the second phase), we used leukocytes from wild-type (WT) and Rac2(-/-) knockout mice. Rac2(-/-) cells displayed an enhanced PLD2 (but not PLD1) enzymatic activity, confirming the inhibitory role of Rac2. Late inhibitory responses on PLD2 due to Rac2 were reversed in the presence of phosphatidylinositol 4,5-bisphosphate (PIP(2)) both in vitro (purified GST-PH-PLD2, where GST is glutathione S-transferase and PH is pleckstrin homology) and in vivo. Coimmunoprecipitation and immunofluorescence microscopy indicated that PLD2 and Rac2 remain together. The presence of an "arc" of Rac2 at the leading edge of leukocyte pseudopodia and PLD2 physically posterior to this wave of Rac2 was observed in late chemotaxis. We propose Rac-led inhibition of PLD2 function is due to sterical interference of Rac with PLD2's PH binding site to the membrane and deprivation of the PIP(2). This work supports the importance of functional interactions between PLD and Rac in the biological response of cell migration.
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Affiliation(s)
- Hong-Juan Peng
- Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
| | - Karen M. Henkels
- Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
| | - Madhu Mahankali
- Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
| | - Christophe Marchal
- Department of Pediatrics (Hematology/Oncology), Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Paula Bubulya
- Department of Biological Sciences, Wright State University, Dayton, Ohio 45435
| | - Mary C. Dinauer
- Department of Pediatrics (Hematology/Oncology), Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Julian Gomez-Cambronero
- Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
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Momboisse F, Houy S, Ory S, Calco V, Bader MF, Gasman S. How important are Rho GTPases in neurosecretion? J Neurochem 2011; 117:623-31. [PMID: 21392006 DOI: 10.1111/j.1471-4159.2011.07241.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Rho GTPases are small GTP binding proteins belonging to the Ras superfamily which act as molecular switches that regulate many cellular function including cell morphology, cell to cell interaction, cell migration and adhesion. In neuronal cells, Rho GTPases have been proposed to regulate neuronal development and synaptic plasticity. However, the role of Rho GTPases in neurosecretion is poorly documented. In this review, we discuss data that highlight the importance of Rho GTPases and their regulators into the control of neurotransmitter and hormone release in neurons and neuroendocrine cells, respectively.
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Affiliation(s)
- Fanny Momboisse
- CNRS UPR 3212, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
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Rho GTPases and exocytosis: what are the molecular links? Semin Cell Dev Biol 2010; 22:27-32. [PMID: 21145407 DOI: 10.1016/j.semcdb.2010.12.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Revised: 12/01/2010] [Accepted: 12/01/2010] [Indexed: 02/08/2023]
Abstract
Delivery of proteins or lipids to the plasma membrane or into the extracellular space occurs through exocytosis, a process that requires tethering, docking, priming and fusion of vesicles, as well as F-actin rearrangements in response to specific extracellular cues. GTPases of the Rho family have been implicated as important regulators of exocytosis, but how Rho proteins control this process is an open question. In this review, we focus on molecular connections that drive Rho-dependent exocytosis in polarized and regulated exocytosis. Specifically, we present data showing that Rho proteins interaction with the exocyst complex and IQGAP mediates polarized exocytosis, whereas interaction with actin-binding proteins like N-WASP mediates regulated exocytosis.
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Momboisse F, Ory S, Ceridono M, Calco V, Vitale N, Bader MF, Gasman S. The Rho Guanine Nucleotide Exchange Factors Intersectin 1L and β-Pix Control Calcium-Regulated Exocytosis in Neuroendocrine PC12 Cells. Cell Mol Neurobiol 2010; 30:1327-33. [DOI: 10.1007/s10571-010-9580-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 09/02/2010] [Indexed: 12/23/2022]
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Popoff MR, Poulain B. Bacterial toxins and the nervous system: neurotoxins and multipotential toxins interacting with neuronal cells. Toxins (Basel) 2010; 2:683-737. [PMID: 22069606 PMCID: PMC3153206 DOI: 10.3390/toxins2040683] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2010] [Revised: 03/18/2010] [Accepted: 04/07/2010] [Indexed: 12/13/2022] Open
Abstract
Toxins are potent molecules used by various bacteria to interact with a host organism. Some of them specifically act on neuronal cells (clostridial neurotoxins) leading to characteristics neurological affections. But many other toxins are multifunctional and recognize a wider range of cell types including neuronal cells. Various enterotoxins interact with the enteric nervous system, for example by stimulating afferent neurons or inducing neurotransmitter release from enterochromaffin cells which result either in vomiting, in amplification of the diarrhea, or in intestinal inflammation process. Other toxins can pass the blood brain barrier and directly act on specific neurons.
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Affiliation(s)
- Michel R. Popoff
- Neurotransmission et Sécrétion Neuroendocrine, CNRS UPR 2356 IFR 37 - Neurosciences, Centre de Neurochimie, 5, rue Blaise Pascal, F-67084 STRASBOURG cedex, France;
- Author to whom correspondence should be addressed;
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Synthesis of fusogenic lipids through activation of phospholipase D1 by GTPases and the kinase RSK2 is required for calcium-regulated exocytosis in neuroendocrine cells. Biochem Soc Trans 2010; 38:167-71. [DOI: 10.1042/bst0380167] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Exocytosis of hormones occurs through the fusion of large dense-core secretory vesicles with the plasma membrane. This highly regulated process involves key proteins such as SNAREs (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptors) and also specific lipids at the site of membrane fusion. Among the different lipids required for exocytosis, our recent observations have highlighted the crucial role of PA (phosphatidic acid) in the late stages of membrane fusion in various exocytotic events. An RNAi (RNA interference) strategy coupled with the detection of PA in living cells has pointed to plasma membrane-associated PLD1 (phospholipase D1) as the main producer of PA in response to secretagogue stimulation. We have identified several GTPases which regulate the activation level of PLD1 in neuroendocrine cells. Finally, RSK2 (ribosomal S6 kinase 2) appears to phosphorylate and regulate the activity of PLD1 in a calcium-dependent manner. Altogether our results have unravelled a complex set of regulatory pathways controlling the synthesis of fusogenic lipids at the secretory granule fusion site by PLD1.
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Bader MF, Vitale N. Phospholipase D in calcium-regulated exocytosis: Lessons from chromaffin cells. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:936-41. [DOI: 10.1016/j.bbalip.2009.02.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2008] [Revised: 02/23/2009] [Accepted: 02/26/2009] [Indexed: 10/21/2022]
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