Novel CARD-9, CARD-10, or CARD-11 polypeptides, proteins, and nucleic acid molecules are disclosed. In addition to isolated CARD-9, CARD-10, or CARD-11 proteins, the invention further provides CARD-9, CARD-10, or CARD-11, fusion proteins, antigenic peptides and anti-CARD-9, CARD-10, or CARD-11 antibodies. The invention also provides CARD-9, CARD-10, or CARD-11 nucleic acid molecules, recombinant expression vectors containing a nucleic acid molecule of the invention, host cells into which the expression vectors have been introduced and non-human transgenic animals in which a CARD-9, CARD-10, or CARD-11 gene has been introduced or disrupted. Diagnostic, screening and therapeutic methods utilizing compositions of the invention are also provided.