SHP-2 phosphatase negatively regulates the TRIF adaptor protein-dependent type I interferon and proinflammatory cytokine production

Abstract

The Toll-like receptor 3 (TLR3) and TLR4-signaling pathway that involves the adaptor protein TRIF activates type I interferon (IFN) and proinflammatory cytokine expression. Little is known about how TRIF pathway-dependent gene expression is regulated. SH2-containing protein tyrosine phosphatase 2 (SHP-2) is a widely expressed cytoplasmic tyrosine phosphatase. Here we demonstrate that SHP-2 negatively regulated TLR4- and TLR3-activated IFN-beta production. SHP-2 inhibited TLR3-activated but not TLR2-, TLR7-, and TLR9-activated proinflammatory cytokine IL-6 and TNF-alpha production. SHP-2 inhibited poly(I:C)-induced cytokine production by a phosphatase activity-independent mechanism. C-terminal domain of SHP-2 directly bound TANK binding kinase (TBK1) by interacting with the kinase domain of TBK1. SHP-2 deficiency increased TBK1-activated IFN-beta and TNF-alpha expression. TBK1 knockdown inhibited poly(I:C)-induced IL-6 production in SHP-2-deficient cells. SHP-2 also inhibited poly(I:C)-induced activation of MAP kinase pathways. These results demonstrate that SHP-2 specifically negatively regulate TRIF-mediated gene expression in TLR signaling, partially through inhibiting TBK1-activated signal transduction.