• Authors: Yang, M., Wang, C., Zhu, X., Tang, S., Shi, L., Cao, X., Chen, T.
  • Year: 2011
  • Journal: J Exp Med 208 2099-112
  • Applications: in vitro / DNA, siRNA / INTERFERin, jetPEI-Macrophage
  • Cell type: Mouse bone marrow-derived denditric cells


The carboxyl terminus of constitutive heat shock cognate 70 (HSC70)-interacting protein (CHIP, also known as Stub1) is a U box-containing E3 ubiquitin ligase that is important for protein quality control. The role of CHIP in innate immunity is not known. Here, we report that CHIP knockdown inhibits Toll-like receptor (TLR) 4- and TLR9-driven signaling, but not TLR3-driven signaling; proinflammatory cytokine and type 1 interferon (IFN) production; and maturation of antigen-presenting cells, including macrophages and dendritic cells. We demonstrate that CHIP can recruit the tyrosine kinase Src and atypical protein kinase C zeta (PKCzeta) to the TLR complex, thereby leading to activation of IL-1 receptor-associated kinase 1, TANK-binding kinase 1, and IFN regulatory factors 3 and 7. CHIP acts as an E3 ligase for Src and PKCzeta during TLR signaling. CHIP-mediated enhancement of TLR signaling is inhibited by IFNAR deficiency or expression of ubiquitination resistant mutant forms of Src or PKCzeta. These findings suggest that CHIP facilitates the formation of a TLR signaling complex by recruiting, ubiquitinating, and activating Src and PKCzeta.