title: The scaffold protein prohibitin is required for antigen-stimulated signaling in mast cells.
abstract: The protein prohibitin (PHB) is implicated in diverse cellular processes, including cell signaling, transcriptional control, and mitochondrial function. We found that PHB was abundant in the intracellular granules of mast cells, which are critical for allergic responses to antigens. Thus, we investigated whether PHB played a role in signaling mediated by the high-affinity receptor for antigen-bound immunoglobulin E (IgE), FcεRI. PHB-specific small interfering RNAs (siRNAs) inhibited antigen-mediated signaling, degranulation, and cytokine secretion by mast cells in vitro. Knockdown of PHB inhibited the antigen-dependent association of the tyrosine kinase Syk with FcεRI and inhibited the activation of Syk. Fractionation studies revealed that PHB translocated from intracellular granules to plasma membrane lipid rafts in response to antigen, and knockdown of PHB suppressed the movement of FcεRIγ and Syk into lipid rafts. Tyrosine phosphorylation of PHB by Lyn was observed early after exposure to antigen, and point mutations in PHB indicated that Tyr(114) and Tyr(259) were required for the recruitment of Syk to FcεRIγ and mast cell activation. In mice, PHB-specific siRNAs inhibited antigen-initiated mast cell degranulation, passive cutaneous anaphylaxis, and passive systemic anaphylaxis. Together, these results suggest that PHB is essential for FcεRI-mediated mast cell activation and allergic responses in vivo, raising the possibility that PHB might serve as a therapeutic target for the treatment of allergic diseases.
authors.affiliation: 1Department of Immunology and Physiology and Functional Genomics Institute, College of Medicine, Konkuk University, Chungju 380-701, Korea.
authors.forename: Do Kyun
authors.initials: DK
authors.lastname: Kim
authors.forename: Hyuk Soon
authors.initials: HS
authors.lastname: Kim
authors.forename: A-Ram
authors.initials: AR
authors.lastname: Kim
authors.forename: Geun Hyo
authors.initials: GH
authors.lastname: Jang
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Kim
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Park
authors.forename: Bokyung
authors.initials: B
authors.lastname: Kim
authors.forename: Yeong Min
authors.initials: YM
authors.lastname: Park
authors.forename: Michael A
authors.initials: MA
authors.lastname: Beaven
authors.forename: Young Mi
authors.initials: YM
authors.lastname: Kim
authors.forename: Wahn Soo
authors.initials: WS
authors.lastname: Choi
mesh_terms: D000818:Animals; D000941:Antigens / Q000276:immunology*; D015153:Blotting, Western; D015550:Cell Degranulation / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D007073:Immunoglobulin E / Q000276:immunology / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000276:immunology / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D018448:Models, Immunological; D009154:Mutation; D010323:Passive Cutaneous Anaphylaxis / Q000235:genetics / Q000276:immunology; D010766:Phosphorylation / Q000276:immunology; D000091402:Prohibitins; D011485:Protein Binding / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000276:immunology / Q000378:metabolism; D034622:RNA Interference; D017455:Receptors, IgE / Q000276:immunology / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D000072377:Syk Kinase; D014443:Tyrosine / Q000276:immunology / Q000378:metabolism
chemical_list: D000941:Antigens; D016207:Cytokines; D047908:Intracellular Signaling Peptides and Proteins; D000091402:Prohibitins; D017455:Receptors, IgE; D012097:Repressor Proteins; D007073:Immunoglobulin E; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C000606897:Syk protein, mouse