PYD and CARD domain-containing protein (commonly known as "Apoptosis-associated speck-like protein containing a CARD") (PYCARD (commonly used abbreviation: ASC))

PYD and CARD domain-containing protein (PYCARD, also called ASC) is a cytoplasmic adaptor protein composed of an N-terminal PYRIN domain (PYD) and a C-terminal caspase recruitment domain (CARD), belonging to the death domain-fold superfamily[1][2]. It plays a central role in the assembly of inflammasomes by bridging upstream pattern-recognition receptors (such as NLRP3 and AIM2) with caspase-1, facilitating the formation of filamentous specks that nucleate caspase-1 activation[1][2]. This leads to the proteolytic processing of pro-inflammatory cytokines (such as IL-1β and IL-18) and induction of inflammatory cell death known as pyroptosis[1][2][3]. PYCARD is implicated in multiple pathways of innate immunity and inflammation, and its altered function or silencing is implicated in autoinflammatory diseases and cancer[2].

Other names

ASCTMS1hASCTMS-1CARD5apoptosis-associated speck-like protein containing a CARDcaspase recruitment domain-containing protein 5target of methylation-induced silencing 1

Drugs modulating the inflammasome generally act by inhibiting NLRP3 activation (preventing PYCARD recruitment and speck formation), caspase-1 activation, or downstream cytokine maturation.