PYCARD Protein, Human (HEK293, His-Myc)

PYCARD protein serves as a pivotal mediator in apoptosis and inflammation, playing multifaceted roles in cellular processes. It facilitates caspase-mediated apoptosis, predominantly involving caspase-8 and, in specific cell types, caspase-9. PYCARD is integral to the activation of the mitochondrial apoptotic pathway, promoting caspase-8-dependent proteolytic maturation of BID independently of FADD, as well as mediating mitochondrial translocation of BAX, initiating BAX-dependent apoptosis coupled with the activation of caspase-9, -2, and -3. Furthermore, PYCARD is a crucial adapter in the assembly of various inflammasomes, including NLRP1, NLRP2, NLRP3, NLRP6, AIM2, and likely IFI16, leading to caspase-1 activation, pro-inflammatory cytokine processing, and inflammation. In cooperation with NOD2, PYCARD participates in an inflammasome activated by bacterial muramyl dipeptide. Additionally, it may be involved in RIGI-triggered pro-inflammatory responses and inflammasome activation. In adaptive immunity, PYCARD contributes to dendritic cell maturation, stimulating T-cell immunity, and modulates cytoskeletal rearrangements associated with chemotaxis and antigen uptake. Furthermore, it plays a role in the transcriptional activation of cytokines and chemokines, independently of the inflammasome, through signaling pathways involving AP-1, NF-kappa-B, MAPK, and caspase-8. The regulatory functions of PYCARD include modulation of NF-kappa-B induction at the IKK complex level, inhibiting kinase activity of CHUK and IKBK. It is proposed to compete with RIPK2, down-regulating CASP1-mediated RIPK2-dependent NF-kappa-B activation, and activating interleukin-1 beta processing. In host resistance to DNA virus infection, PYCARD likely induces the cleavage and inactivation of CGAS in the presence of cytoplasmic double-stranded DNA, showcasing its diverse and critical roles in cellular responses.