title: Regulation of FcepsilonRI-mediated signaling by an adaptor protein STAP-2/BSK in rat basophilic leukemia RBL-2H3 cells.
abstract: Crosslinking of multivalent antigen bound IgE transduces FcepsilonRI mediated signaling cascades, which activate nonreceptor-type protein-tyrosine kinases and subsequent tyrosine phosphorylation of cellular proteins, and these are critical elements for degranulation in mast cells. We cloned a novel adaptor molecule, signal transducing adaptor protein (STAP)-2 containing PH and SH2-like domains as a c-fms interacting protein. STAP-2 was identical to a recently cloned adaptor molecule, BKS, a substrate of BRK (breast tumor kinase) tyrosine kinase, although its function is still unknown. To examine a novel function of STAP-2/BSK, we expressed STAP-2/BSK or its mutants in rat basophilic leukemia RBL-2H3 cells. Overexpression of STAP-2/BSK resulted in a suppression of FcepsilonRI-mediated calcium mobilization and degranulation. FcepsilonRI-induced tyrosine phosphorylation of phospholipase C-gamma (PLC-gamma) but not Syk was significantly suppressed in these cells. Furthermore, STAP-2/BSK associated with PLC-gamma in vivo. These data indicate that STAP-2/BSK negatively controls the FcepsilonRI-mediated calcium mobilization and degranulation by direct modulation of tyrosine phosphorylation of PLC-gamma.
authors.affiliation: Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-Ku Kita 12 Nishi 6, 060-0812, Sapporo, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Taro
authors.initials: T
authors.lastname: Yumioka
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Sekine
authors.forename: Noriko
authors.initials: N
authors.lastname: Sato
authors.forename: Mayu
authors.initials: M
authors.lastname: Minoguchi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshimura
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism; D017930:Genes, Reporter; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D015471:Leukemia, Basophilic, Acute; D008407:Mast Cells / Q000166:cytology / Q000378:metabolism; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D051966:Phospholipase C gamma; D010750:Phosphoproteins; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D017455:Receptors, IgE / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology* / Q000502:physiology; D000072377:Syk Kinase; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D004268:DNA-Binding Proteins; D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010750:Phosphoproteins; D017455:Receptors, IgE; D011993:Recombinant Fusion Proteins; C413897:STAP2 protein, human; D014157:Transcription Factors; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; C000606898:Syk protein, rat; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D002118:Calcium