The inflammasome adaptor ASC regulates the function of adaptive immune cells by controlling Dock2-mediated Rac activation and actin polymerization.

ABSTRACT: The adaptor ASC contributes to innate immunity through the assembly of inflammasome complexes that activate the cysteine protease caspase-1. Here we demonstrate that ASC has an inflammasome-independent, cell-intrinsic role in cells of the adaptive immune response. ASC-deficient mice showed defective antigen presentation by dendritic cells (DCs) and lymphocyte migration due to impaired actin polymerization mediated by the small GTPase Rac. Genome-wide analysis showed that ASC, but not the cytoplasmic receptor NLRP3 or caspase-1, controlled the mRNA stability and expression of Dock2, a guanine nucleotide-exchange factor that mediates Rac-dependent signaling in cells of the immune response. Dock2-deficient DCs showed defective antigen uptake similar to that of ASC-deficient cells. Ectopic expression of Dock2 in ASC-deficient cells restored Rac-mediated actin polymerization, antigen uptake and chemotaxis. Thus, ASC shapes adaptive immunity independently of inflammasomes by modulating Dock2-dependent Rac activation and actin polymerization in DCs and lymphocytes.

SUBMITTER: Ippagunta SK 

PROVIDER: S-EPMC3178750 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature