Enables CARD domain binding activity. Involved in several processes, including antifungal innate immune response; host-mediated regulation of intestinal microbiota composition; and positive regulation of cytokine production. Acts upstream of or within several processes, including positive regulation of JNK cascade; regulation of cytokine production; and response to bacterium. Part of CBM complex. Human ortholog(s) of this gene implicated in chronic mucocutaneous candidiasis. Orthologous to human CARD9 (caspase recruitment domain family member 9). [provided by Alliance of Genome Resources, Apr 2022]