Evidence of a role for Munc18-2 and microtubules in mast cell granule exocytosis

Martin-Verdeaux, Sophie; Pombo, Isabel; Iannascoli, Bruno; Roa, Michèle; Varin‐Blank, Nadine; Rivera, Juan; Blank, Ulrich

doi:10.1242/jcs.00216

Cited by 120 publications

(124 citation statements)

References 66 publications

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“…This finding is in accordance with previously published data demonstrating microtubule-dependent movement of secretory vesicles during exocytotic response (16,17,20) and studies documenting a dramatic decrease in degranulation, but not in Ca 2+ response in nocodazole treated cells (49). Our observation that STIM1 puncta are associated with microtubules in protrusions (Fig.…”

Section: Discussionsupporting

confidence: 94%

“…Accumulating recent data point to an important role of microtubules in these processes (38). Previous studies focused primarily on the role of microtubules in granular transport (13,16,17,20) or on the initial stages of SOCE signaling pathway (13,15,39). In this study, we show that microtubule network rearrangement in activated BMMCs and formation of microtubule protrusions is dependent on the activity of Ca 2+ sensor STIM1.…”

Section: Discussionsupporting

confidence: 52%

“…This finding is supported by demonstrations that agents inhibiting tubulin polymerization also suppress degranulation (18)(19)(20). Importantly, FcεRI aggregation triggers reorganization of microtubules and their concentration in cell periphery (17,21).…”

mentioning

confidence: 76%

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STIM1-Directed Reorganization of Microtubules in Activated Mast Cells

Hájková

Bugajev

Dráberová

et al. 2011

The Journal of Immunology

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Activation of mast cells by aggregation of the high-affinity IgE receptors (FcεRI) initiates signaling events leading to the release of inflammatory and allergic mediators stored in cytoplasmic granules. A key role in this process play changes in concentrations of intracellular Ca2+ controlled by store-operated Ca2+ entry (SOCE). Although microtubules are also involved in the process leading to degranulation, the molecular mechanisms that control microtubule rearrangement during activation are largely unknown. In this study, we report that activation of bone marrow-derived mast cells (BMMCs) induced by FcεRI aggregation or treatment with pervanadate or thapsigargin results in generation of protrusions containing microtubules (microtubule protrusions). Formation of these protrusions depended on the influx of extracellular Ca2+. Changes in cytosolic Ca2+concentration also affected microtubule plus-end dynamics detected by microtubule plus-end tracking protein EB1. Experiments with knockdown or reexpression of STIM1, the key regulator of SOCE, confirmed the important role of STIM1 in the formation of microtubule protrusions. Although STIM1 in activated cells formed puncta associated with microtubules in protrusions, relocation of STIM1 to a close proximity of cell membrane was independent of growing microtubules. In accordance with the inhibition of Ag-induced Ca2+ response and decreased formation of microtubule protrusions in BMMCs with reduced STIM1, the cells also exhibited impaired chemotactic response to Ag. We propose that rearrangement of microtubules in activated mast cells depends on STIM1-induced SOCE, and that Ca2+ plays an important role in the formation of microtubule protrusions in BMMCs.

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Section: Discussionsupporting

confidence: 94%

Section: Discussionsupporting

confidence: 52%

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STIM1-Directed Reorganization of Microtubules in Activated Mast Cells

Hájková

Bugajev

Dráberová

et al. 2011

The Journal of Immunology

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“…Accumulating data point to the importance of microtubules in this process (3,4,7,34). We showed previously that the stimulation of mast cells or basophils through FcεRI aggregation or by pervanadate exposure triggers the generation of complexes containing g-tubulin, tyrosine-phosphorylated proteins, and tyrosine kinases (5,35) and the reorganization of microtubules (5,6).…”

Section: Discussionmentioning

confidence: 99%

“…Microtubules, built up from ab-tubulin heterodimers, are important for mast cell degranulation, because the movement of secretory granules depends on intact microtubules (2,3), and compounds inhibiting tubulin polymerization suppress degranulation (4). It was reported that FcεRI aggregation leads to reorganization of microtubules (3,5) and that the influx of Ca 2+ plays a decisive role in microtubule remodeling (6,7).…”

mentioning

confidence: 99%

Microtubule Nucleation in Mouse Bone Marrow–Derived Mast Cells Is Regulated by the Concerted Action of GIT1/βPIX Proteins and Calcium

Sulimenko

Hájková

Černohorská

et al. 2015

The Journal of Immunology

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Ag-mediated activation of mast cells initiates signaling events leading to Ca2+ response, release of allergic mediators from cytoplasmic granules, and synthesis of cytokines and chemokines. Although microtubule rearrangement during activation has been described, the molecular mechanisms that control their remodeling are largely unknown. Microtubule nucleation is mediated by complexes that are formed by γ-tubulin and γ-tubulin complex proteins. In this study, we report that, in bone marrow–derived mast cells (BMMCs), γ-tubulin interacts with p21-activated kinase interacting exchange factor β (βPIX) and G protein–coupled receptor kinase-interacting protein (GIT)1. Microtubule regrowth experiments showed that the depletion of βPIX in BMMCs stimulated microtubule nucleation, whereas depletion of GIT1 led to the inhibition of nucleation compared with control cells. Phenotypic rescue experiments confirmed that βPIX and GIT1 represent negative and positive regulators of microtubule nucleation in BMMCs, respectively. Live-cell imaging disclosed that both proteins are associated with centrosomes. Immunoprecipitation and pull-down experiments revealed that an enhanced level of free cytosolic Ca2+ affects γ-tubulin properties and stimulates the association of GIT1 and γ-tubulin complex proteins with γ-tubulin. Microtubule nucleation also was affected by Ca2+ level. Moreover, in activated BMMCs, γ-tubulin formed complexes with tyrosine-phosphorylated GIT1. Further experiments showed that GIT1 and βPIX are involved in the regulation of such important physiological processes as Ag-induced chemotaxis and degranulation. Our study provides for the first time, to our knowledge, a possible mechanism for the concerted action of tyrosine kinases, GIT1/βPIX proteins, and Ca2+ in the propagation of signals leading to the regulation of microtubule nucleation in activated mast cells.

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Lysosome Exocytosis and Membrane Repair

Singh

Haka

2016

Lysosomes: Biology, Diseases, and Therapeutics

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Evidence of a role for Munc18-2 and microtubules in mast cell granule exocytosis

Cited by 120 publications

References 66 publications

STIM1-Directed Reorganization of Microtubules in Activated Mast Cells

STIM1-Directed Reorganization of Microtubules in Activated Mast Cells

Microtubule Nucleation in Mouse Bone Marrow–Derived Mast Cells Is Regulated by the Concerted Action of GIT1/βPIX Proteins and Calcium

Lysosome Exocytosis and Membrane Repair

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