Signal-transducing adaptor protein-2 has a nonredundant role for IL-33-triggered mast cell activation

Signal-transducing adaptor protein (STAP)-2 is one of the STAP family adaptor proteins and ubiquitously expressed in a variety types of cells. Although STAP-2 is required for modification of Fc epsilon RI signal transduction in mast cells, other involvement of STAP-2 in mast cell functions is unknown, yet. In the present study, we mainly investigated functional roles of STAP-2 in IL-33-induced mast cell activation. In STAP-2-deficient, but not STAP-1-deficient, mast cells, IL-33-induced IL-6 and TNF-alpha production was significantly decreased compared with that of wild-type mast cells. In addition, STAP-2-deficiency greatly reduced TLR4-mediated mast cell activation and cytokine production. For the mechanisms, STAP-2 directly binds to IKK alpha after IL-33 stimulation, leading to elevated NF-kappa B activity. In conclusion, STAP-2, but not STAP-1, participates in IL-33-induced mast cells activation. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

STAP-2 is an essential adaptor protein involved in regulating mast cell activation, particularly in response to IL-33 stimulation. Its deficiency leads to decreased cytokine production and impaired TLR4-mediated mast cell activation. The direct binding of STAP-2 to IKKα enhances NF-kappa B activity, contributing to the activation of mast cells.