Asc (Tyr-144), Phosphospecific Antibody

Host- and pathogen-associated cytoplasmic double-stranded DNA triggers the activation of a NALP3-independent inflammasome, which activates caspase-1, leading to maturation of pro-interleukin-1beta and inflammation. Several studies have isolated AIM2 (absent in melanoma 2) as a candidate cytoplasmic-DNA-sensing protein that contains an N-terminal pyrin domain and C-terminal oligonucleotide binding domain. A screen for transcripts induced by interferon-beta identified AIM2 gene expression. AIM2 protein bound double-stranded DNA, recruited the inflammasome adaptor ASC, and localized to ASC containing speckles. AIM2 and ASC form a pyroptosome, which induces pyroptotic cell death mediated by caspase-1. Asc can be phosphorylated at Tyr-144 in a Syk and JNK-dependent manner. This phosphorylation is critical for Asc speck formation and Caspase-1 activation.

Asc (Tyr-144) phospho-peptide (coupled to KLH) corresponding to amino acid residues surrounding Tyr-144 in mouse Asc. This peptide sequence is highly conserved in human and rat Asc.

This antibody was cross-adsorbed to unphosphorylated Asc (Tyr-144) peptide before affinity purification using phospho-Asc (Tyr-144) peptide. The antibody detects phosphorylated Asc (Tyr-144) in the inflammasome. In J774 macrophage cells primed with LPS and treated with nigericin, the antibody colocalized with an inflammasome marker, caspase-1 inhibitor (FAM-YVAD-FMK) . In addition, the antibody detects a 20 kDa Asc protein in western blots of J774A.1 mouse macrophages treated with pervanadate.