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Brochetta C, Suzuki R, Vita F, Soranzo MR, Claver J, Madjene LC, Attout T, Vitte J, Varin-Blank N, Zabucchi G, Rivera J, Blank U. Munc18-2 and syntaxin 3 control distinct essential steps in mast cell degranulation. THE JOURNAL OF IMMUNOLOGY 2013; 192:41-51. [PMID: 24323579 DOI: 10.4049/jimmunol.1301277] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mast cell degranulation requires N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) and mammalian uncoordinated18 (Munc18) fusion accessory proteins for membrane fusion. However, it is still unknown how their interaction supports fusion. In this study, we found that small interfering RNA-mediated silencing of the isoform Munc18-2 in mast cells inhibits cytoplasmic secretory granule (SG) release but not CCL2 chemokine secretion. Silencing of its SNARE-binding partner syntaxin 3 (STX3) also markedly inhibited degranulation, whereas combined knockdown produced an additive inhibitory effect. Strikingly, while Munc18-2 silencing impaired SG translocation, silencing of STX3 inhibited fusion, demonstrating unique roles of each protein. Immunogold studies showed that both Munc18-2 and STX3 are located on the granule surface, but also within the granule matrix and in small nocodazole-sensitive clusters of the cytoskeletal meshwork surrounding SG. After stimulation, clusters containing both effectors were detected at fusion sites. In resting cells, Munc18-2, but not STX3, interacted with tubulin. This interaction was sensitive to nocodazole treatment and decreased after stimulation. Our results indicate that Munc18-2 dynamically couples the membrane fusion machinery to the microtubule cytoskeleton and demonstrate that Munc18-2 and STX3 perform distinct, but complementary, functions to support, respectively, SG translocation and membrane fusion in mast cells.
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Affiliation(s)
- Cristiana Brochetta
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Ryo Suzuki
- Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892
| | - Francesca Vita
- Department of Life Sciences Department of Physiology and Pathology, University of Trieste, Italy
| | - Maria Rosa Soranzo
- Department of Life Sciences Department of Physiology and Pathology, University of Trieste, Italy
| | - Julien Claver
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Lydia Celia Madjene
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Tarik Attout
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Joana Vitte
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
| | - Nadine Varin-Blank
- Inserm U978, 93000 Bobigny, France.,Laboratoire d'excellence "Inflamex," Unité de Formation et de Recherche Santé-Médecine-Biologie Humaine, 93000 Bobigny, France
| | - Giuliano Zabucchi
- Department of Life Sciences Department of Physiology and Pathology, University of Trieste, Italy
| | - Juan Rivera
- Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892
| | - Ulrich Blank
- Inserm UMRS-699, 75018 Paris, France.,Université Paris Diderot, Sorbonne Paris Cite, Laboratoire d'excellence INFLAMEX, 75018 Paris, France
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Leung WH, Bolland S. The inositol 5'-phosphatase SHIP-2 negatively regulates IgE-induced mast cell degranulation and cytokine production. THE JOURNAL OF IMMUNOLOGY 2007; 179:95-102. [PMID: 17579026 DOI: 10.4049/jimmunol.179.1.95] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aggregation of the high-affinity IgE receptor (FcepsilonRI) on mast cells initiates signaling pathways leading to degranulation and cytokine release. It has been reported that SHIP-1 negatively regulates FcepsilonRI-triggered pathways but it is unknown whether its homologous protein SHIP-2 has the same function. We have used a lentiviral-based RNA interference technique to obtain SHIP-2 knockdown bone marrow-derived mast cells (BMMCs) and have found that elimination of SHIP-2 results in both increased mast cell degranulation and cytokine (IL-4 and IL-13) gene expression upon FcepsilonRI stimulation. Elimination of SHIP-2 from BMMCs has no effect on FcepsilonRI-triggered calcium flux, tyrosine phosphorylation of MAPKs or in actin depolymerization following activation. Rather, we observe that absence of SHIP-2 results in increased activation of the small GTPase Rac-1 and in enhanced microtubule polymerization upon FcepsilonRI engagement. Coimmunoprecipitation experiments in rat basophilic leukemia (RBL 2H3) cells show that SHIP-2 interacts with the FcepsilonRI beta-chain, Gab2 and Lyn and that unlike SHIP-1, it does not associate with SHC in mast cells. Our results report a negative regulatory role of SHIP-2 on mast cell activation that is calcium independent and distinct from the regulation by SHIP-1.
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Affiliation(s)
- Wai-Hang Leung
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD 20852, USA
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