title: SLP-76 is required for high-affinity IgE receptor- and IL-3 receptor-mediated activation of basophils.
abstract: Basophils have been reported to play a critical role in allergic inflammation by secreting IL-4 in response to IL-3 or high-affinity IgE receptor (FcεRI)-cross-linking. However, the signaling pathways downstream of FcεRI and the IL-3 receptor in basophils have yet to be determined. In the present study, we used mice deficient in SLP-76 (Src homology 2 domain-containing leukocyte phosphoprotein of 76kDa) to demonstrate critical functions of this adaptor molecule in transducing FcεRI- and IL-3 receptor-mediated signals that induce basophil activation. Although SLP-76 was dispensable for in vivo differentiation, as well as IL-3-induced in vitro proliferation of basophils, IL-4 production induced by both stimuli was completely ablated by SLP-76 deficiency. Biochemical analyses revealed that IL-3-induced phosphorylation of phospholipase C (PLC) γ2 and Akt, but not STAT5, was severely reduced in SLP-76-deficient basophils, whereas FcεRI cross-linking phosphorylation of PLCγ2, but not Akt, was abrogated by SLP-76 deficiency, suggesting important differences in the requirement of SLP-76 for Akt activation between FcεRI- and IL-3 receptor-mediated signaling pathways in basophils. Because IL-3-induced IL-4 production was sensitive to calcineurin inhibitors and an intracellular calcium chelator, in addition to PI3K inhibitors, SLP-76 appears to regulate FcεRI- and IL-3 receptor-induced IL-4 production via mediating PLCγ2 activation in basophils. Taken together, these findings indicate that SLP-76 is an essential signaling component for basophil activation downstream of both FcεRI and the IL-3 receptor.
authors.affiliation: Division of Development and Aging, Research Institute for Biological Sciences, 2669 Yamazaki, Noda, Chiba 278-0022, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Hidano
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kitamura
authors.forename: Lalit
authors.initials: L
authors.lastname: Kumar
authors.forename: Raif S
authors.initials: RS
authors.lastname: Geha
authors.forename: Ryo
authors.initials: R
authors.lastname: Goitsuka
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D000818:Animals; D001491:Basophils / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D015151:Immunoblotting; D007377:Interleukin-3 / Q000276:immunology / Q000494:pharmacology; D015847:Interleukin-4 / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D051966:Phospholipase C gamma / Q000276:immunology / Q000378:metabolism; D010750:Phosphoproteins / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D010766:Phosphorylation / Q000276:immunology; D017455:Receptors, IgE / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016185:Receptors, Interleukin-3 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D014443:Tyrosine / Q000276:immunology / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C521907:Fc-epsilon receptor I beta-chain, mouse; C579617:FcepsilonRIalpha protein, mouse; D007377:Interleukin-3; D010750:Phosphoproteins; D017455:Receptors, IgE; D016185:Receptors, Interleukin-3; C092947:SLP-76 signal Transducing adaptor proteins; D015847:Interleukin-4; D014443:Tyrosine; D051966:Phospholipase C gamma