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WIP regulates signaling via the high affinity receptor for immunoglobulin E in mast cells.

Kettner A, Kumar L, Antón IM, Sasahara Y, de la Fuente M, Pivniouk VI, Falet H, Hartwig JH, Geha RS - J. Exp. Med. (2004)

Bottom Line: Calcium mobilization, phosphorylation of Syk, phospholipase C-g2, and c-Jun NH2-terminal kinase were markedly decreased in WIP-deficient BMMCs.However, the kinetics of actin changes and the cell shape changes that follow FcepsilonRI signaling were altered in WIP-deficient BMMCs.These results suggest that WIP regulates FcepsilonRI-mediated mast cell activation by regulating Syk levels and actin cytoskeleton rearrangement.

View Article: PubMed Central - PubMed

Affiliation: Division of Immunology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.

ABSTRACT
Wiskott-Aldrich syndrome protein-interacting protein (WIP) stabilizes actin filaments and is important for immunoreceptor-mediated signal transduction leading to actin cytoskeleton rearrangement in T and B cells. Here we report a role for WIP in signaling pathways downstream of the high affinity receptor for immunoglobulin (Ig)E (FcepsilonRI) in mast cells. WIP-deficient bone marrow-derived mast cells (BMMCs) were impaired in their capacity to degranulate and secrete interleukin 6 after FcepsilonRI ligation. Calcium mobilization, phosphorylation of Syk, phospholipase C-g2, and c-Jun NH2-terminal kinase were markedly decreased in WIP-deficient BMMCs. WIP was found to associate with Syk after FcepsilonRI ligation and to inhibit Syk degradation as evidenced by markedly diminished Syk levels in WIP-deficient BMMCs. WIP-deficient BMMCs exhibited no apparent defect in their subcortical actin network and were normal in their ability to form protrusions when exposed to an IgE-coated surface. However, the kinetics of actin changes and the cell shape changes that follow FcepsilonRI signaling were altered in WIP-deficient BMMCs. These results suggest that WIP regulates FcepsilonRI-mediated mast cell activation by regulating Syk levels and actin cytoskeleton rearrangement.

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Activation of MAP kinases in response to FcεRI ligation. BMMCs were stimulated for the indicated times and lysed in SDS-PAGE sample buffer. Aliquots of the lysates were analyzed in parallel for phosphorylation of ERK1/2 (A), p38 (B), and SAPK/JNK (C) by Western blotting with the corresponding phospho-specific antibodies. Membranes were reprobed with kinase-specific antibodies to control for loading. Representative blots of three experiments are shown. Mean fold induction (n = 3) normalized to signal for loading was determined by densitometry.
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fig5: Activation of MAP kinases in response to FcεRI ligation. BMMCs were stimulated for the indicated times and lysed in SDS-PAGE sample buffer. Aliquots of the lysates were analyzed in parallel for phosphorylation of ERK1/2 (A), p38 (B), and SAPK/JNK (C) by Western blotting with the corresponding phospho-specific antibodies. Membranes were reprobed with kinase-specific antibodies to control for loading. Representative blots of three experiments are shown. Mean fold induction (n = 3) normalized to signal for loading was determined by densitometry.

Mentions: FcεRI cross-linking induces phosphorylation and activation of the MAP kinases Erk, JNK, and p38 in mast cells (15, 36). The phosphorylation status of the MAP kinases Erk, JNK, and p38 in WIP−/− BMMCs after FcεRI cross-linking was examined by Western blotting with antibodies that recognize selectively these kinases in their phosphorylated state. Phosphorylation of Erk and p38 was minimally affected in WIP−/− mast cells compared with WT controls (Fig. 5, A and B). In contrast, FcεRI-mediated phosphorylation of JNK, both p54 and p46 forms, was reduced and less sustained in WIP−/− mast cells (Fig. 5 C).


WIP regulates signaling via the high affinity receptor for immunoglobulin E in mast cells.

Kettner A, Kumar L, Antón IM, Sasahara Y, de la Fuente M, Pivniouk VI, Falet H, Hartwig JH, Geha RS - J. Exp. Med. (2004)

Activation of MAP kinases in response to FcεRI ligation. BMMCs were stimulated for the indicated times and lysed in SDS-PAGE sample buffer. Aliquots of the lysates were analyzed in parallel for phosphorylation of ERK1/2 (A), p38 (B), and SAPK/JNK (C) by Western blotting with the corresponding phospho-specific antibodies. Membranes were reprobed with kinase-specific antibodies to control for loading. Representative blots of three experiments are shown. Mean fold induction (n = 3) normalized to signal for loading was determined by densitometry.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2211794&req=5

fig5: Activation of MAP kinases in response to FcεRI ligation. BMMCs were stimulated for the indicated times and lysed in SDS-PAGE sample buffer. Aliquots of the lysates were analyzed in parallel for phosphorylation of ERK1/2 (A), p38 (B), and SAPK/JNK (C) by Western blotting with the corresponding phospho-specific antibodies. Membranes were reprobed with kinase-specific antibodies to control for loading. Representative blots of three experiments are shown. Mean fold induction (n = 3) normalized to signal for loading was determined by densitometry.
Mentions: FcεRI cross-linking induces phosphorylation and activation of the MAP kinases Erk, JNK, and p38 in mast cells (15, 36). The phosphorylation status of the MAP kinases Erk, JNK, and p38 in WIP−/− BMMCs after FcεRI cross-linking was examined by Western blotting with antibodies that recognize selectively these kinases in their phosphorylated state. Phosphorylation of Erk and p38 was minimally affected in WIP−/− mast cells compared with WT controls (Fig. 5, A and B). In contrast, FcεRI-mediated phosphorylation of JNK, both p54 and p46 forms, was reduced and less sustained in WIP−/− mast cells (Fig. 5 C).

Bottom Line: Calcium mobilization, phosphorylation of Syk, phospholipase C-g2, and c-Jun NH2-terminal kinase were markedly decreased in WIP-deficient BMMCs.However, the kinetics of actin changes and the cell shape changes that follow FcepsilonRI signaling were altered in WIP-deficient BMMCs.These results suggest that WIP regulates FcepsilonRI-mediated mast cell activation by regulating Syk levels and actin cytoskeleton rearrangement.

View Article: PubMed Central - PubMed

Affiliation: Division of Immunology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.

ABSTRACT
Wiskott-Aldrich syndrome protein-interacting protein (WIP) stabilizes actin filaments and is important for immunoreceptor-mediated signal transduction leading to actin cytoskeleton rearrangement in T and B cells. Here we report a role for WIP in signaling pathways downstream of the high affinity receptor for immunoglobulin (Ig)E (FcepsilonRI) in mast cells. WIP-deficient bone marrow-derived mast cells (BMMCs) were impaired in their capacity to degranulate and secrete interleukin 6 after FcepsilonRI ligation. Calcium mobilization, phosphorylation of Syk, phospholipase C-g2, and c-Jun NH2-terminal kinase were markedly decreased in WIP-deficient BMMCs. WIP was found to associate with Syk after FcepsilonRI ligation and to inhibit Syk degradation as evidenced by markedly diminished Syk levels in WIP-deficient BMMCs. WIP-deficient BMMCs exhibited no apparent defect in their subcortical actin network and were normal in their ability to form protrusions when exposed to an IgE-coated surface. However, the kinetics of actin changes and the cell shape changes that follow FcepsilonRI signaling were altered in WIP-deficient BMMCs. These results suggest that WIP regulates FcepsilonRI-mediated mast cell activation by regulating Syk levels and actin cytoskeleton rearrangement.

Show MeSH
Related in: MedlinePlus