$A NOD-$signaling adaptor protein that contains a C-terminal leucine-rich domain which recognizes bacterial PEPTIDOGLYCAN. It signals via an N-terminal caspase recruitment domain that interacts with other CARD SIGNALING ADAPTOR PROTEINS such as RIP SERINE-THEONINE KINASES. It plays a role in the host defense response by signaling the activation of CASPASES and the MAP KINASE SIGNALING SYSTEM.