Regulation of FcεRI-mediated signaling by an adaptor protein STAP-2/BSK in rat basophilic leukemia RBL-2H3 cells

Tetsuya Yamamoto, Taro Yumioka, Yuichi Sekine, Noriko Sato, Mayu Minoguchi, Akihiko Yoshimura, Tadashi Matsuda

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Crosslinking of multivalent antigen bound IgE transduces FcεRI 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 FcεRI-mediated calcium mobilization and degranulation. FcεRI-induced tyrosine phosphorylation of phospholipase C-γ (PLC-γ) but not Syk was significantly suppressed in these cells. Furthermore, STAP-2/BSK associated with PLC-γ in vivo. These data indicate that STAP-2/BSK negatively controls the FcεRI-mediated calcium mobilization and degranulation by direct modulation of tyrosine phosphorylation of PLC-γ.

Original languageEnglish
Pages (from-to)767-773
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number3
Publication statusPublished - 2003 Jul 4
Externally publishedYes


  • High affinity receptor for IgE
  • Phospholipase C-γ
  • Signal transducing adaptor protein-2

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'Regulation of FcεRI-mediated signaling by an adaptor protein STAP-2/BSK in rat basophilic leukemia RBL-2H3 cells'. Together they form a unique fingerprint.

Cite this