Plays a role in inhibiting the effects of BCL10-induced activation of NF-kappa-B. May inhibit the phosphorylation of BCL10 in a CARD-dependent manner. Associates with BCL10 by CARD-CARD interaction (PubMed:15637807). Coexpression with BCL10 induced translocation from nucleus to cytosol. Expressed in ovary, testis, placenta, skeletal muscle, kidney, lung, heart and liver (at protein level). Expressed in thymus and brain. Appears to be the dominant isoform in peripheral blood cell fractions. Contains a transmembrane helix.