Shp2 activates Fyn and Ras to regulate RBL-2H3 mast cell activation following FcεRI aggregation.
The protein-tyrosine phosphatase (PTP) Shp2 has been implicated in many immunoreceptor signaling pathways, but its role in immunoreceptor FcεRI signaling, which leads to the activation of mast cells and blood basophils, is still largely undefined. Using Shp2 knockdown RBL-2H3 (RBL) mast cells, we here reported that Shp2 is required for the activation of RBL cells induced by FcεRI. FcεRΙ-evoked degranulation, calcium mobilization, and synthesis of cytokine transcripts (IL-1β, IL-10, and monocyte chemoattractant protein 1 (MCP-1)) were reduced in Shp2 knockdown RBL cells. Signaling regulatory mechanism investigation using immunoblotting, immunoprecipitation, and GST pull-down assay reveals that the down-regulation of Shp2 expression in RBL cells leads to decreased activities of Fyn, PLCγ, JNK, p38MAPK, and Ras/Erk1/2 after FcεRΙ aggregation. Further studies suggest that Paxillin phosphoryaltion was also impaired, but PAG phosphorylation was normal after FcεRΙ stimulation as a consequence of the inhibition of Shp2 expression in RBL cells. Collectively, our data strongly indicate that Shp2 is essential for the activation of RBL cells in response to FcεRΙ aggregation. Shp2 regulates this process through Fyn and Ras with no involvement of PAG. In addition, we identify Paxillin as an indirect substrate of Shp2 in FcεRΙ-initiated signaling of RBL cells.
The Key Laboratory of Molecular Medicine, Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
Xiaoyun
X
Fang
Yongjiang
Y
Lang
Yuxiong
Y
Wang
Wei
W
Mo
Huanhuan
H
Wei
Jianhui
J
Xie
Min
M
Yu
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015550:Cell Degranulation; D055785:Gene Knockdown Techniques; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000235:genetics / Q000378:metabolism*; D051076:Proto-Oncogene Proteins c-fyn / Q000378:metabolism; D051381:Rats; D017455:Receptors, IgE / Q000276:immunology / Q000502:physiology*; D015398:Signal Transduction; D018631:ras Proteins / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
D017455:Receptors, IgE; C494961:Fyn protein, rat; D051076:Proto-Oncogene Proteins c-fyn; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases; D020928:Mitogen-Activated Protein Kinases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D018631:ras Proteins; D002118:Calcium