Plays a key role in both adaptive and innate immune signaling by bridging CARD domain-containing proteins to immune activation. Acts by channeling adaptive and innate immune signaling downstream of CARD domain-containing proteins CARD9, CARD11 and CARD14 to activate NF-kappa-B and MAP kinase p38 (MAPK11, MAPK12, MAPK13 and/or MAPK14) pathways which stimulate expression of genes encoding pro-inflammatory cytokines and chemokines. Recruited by activated CARD domain-containing proteins: homooligomerized CARD domain-containing proteins form a nucleating helical template that recruits BCL10 via CARD-CARD interaction, thereby promoting polymerization of BCL10, subsequent recruitment of MALT1 and formation of a CBM complex. This leads to activation of NF-kappa-B and MAP kinase p38 (MAPK11, MAPK12, MAPK13 and/or MAPK14) pathways which stimulate expression of genes encoding pro-inflammatory cytokines and chemokines. Activated by CARD9 downstream of C-type lectin receptors; CARD9-mediated signals are essential for antifungal immunity. Activated by CARD11 downstream of T-cell receptor (TCR) and B-cell receptor (BCR). Promotes apoptosis, pro-caspase-9 maturation and activation of NF-kappa-B via NIK and IKK. Homomultimer; homooligomerized following recruitment by CARD domain-containing proteins that form a nucleating helical template that recruits BCL10 via CARD-CARD interaction. Self-associates by CARD-CARD interaction and interacts with other CARD-proteins such as CARD9, CARD10, CARD11 and CARD14. Forms a complex with CARD14 and MALT1; resulting in the formation of a CBM (CARD14-BCL10-MALT1) complex. Forms a complex with CARD11 and MALT1; resulting in the formation of a CBM (CARD11-BCL10-MALT1) complex (By similarity). Forms a complex with CARD9 and MALT1; resulting in the formation of a CBM (CARD9-BCL10-MALT1) complex (By similarity). Found in a membrane raft complex, at least composed of BCL10, CARD11, DPP4 and IKBKB. Binds caspase-9 with its C-terminal domain. Interacts with TRAF2 and BIRC2/c-IAP2 (By similarity). Interacts with PELI2 and SOCS3; these interactions may be mutually exclusive (By similarity). Appears to have a perinuclear, compact and filamentous pattern of expression. Also found in the nucleus of several types of tumor cells. Colocalized with DPP4 in membrane rafts. Phosphorylated. Phosphorylation results in dissociation from TRAF2 and binding to BIRC2/c-IAP2. Phosphorylated by IKBKB/IKKB. Ubiquitinated via both 'Lys-63'-linked and linear ('Met-1'-linked) polyubiquitin chains in response to T-cell receptor (TCR) activation. Ubiquitination is recognized by IKBKG/NEMO, the regulatory subunit of I-kappa-B kinase (IKK), and is required for TCR-induced NF-kappa-B activation. Linear ubiquitination at Lys-17, Lys-31 and Lys-63 is mediated by RNF31/HOIP; linear ubiquitination is recognized with much higher affinity than 'Lys-63'-linked ubiquitin by IKBKG/NEMO. CARD11 is required for linear ubiquitination by HOIP by promoting the targeting of BCL10 to RNF31/HOIP. Proteolytically cleaved by MALT1; required for T-cell activation.