Caspaser

Caspaser is not a widely recognized term in mainstream biology and may be a misspelling or variant of caspase. The article here adopts the standard meaning associated with caspases, a family of cysteine-aspartic proteases that regulate programmed cell death and inflammatory responses.

Caspases are synthesized as inactive zymogens (procaspases) that contain an N-terminal prodomain and a catalytic domain. Activation occurs by proteolytic processing, which creates two subunits that assemble into an active heterotetramer. Initiator caspases (for example caspase-2, -8, -9, -10) are typically activated by adaptor proteins in response to cellular stress and then activate downstream executioner caspases (such as caspase-3, -6, -7) that dismantle cellular components. Inflammatory caspases (including caspase-1, -4, -5 in humans and caspase-11 in mice) participate in cytokine maturation and inflammatory cell death.

There are three major regulatory pathways. The intrinsic (mitochondrial) pathway releases cytochrome c, leading to apoptosome formation and activation of caspase-9, which then activates executioners. The extrinsic pathway involves death receptors that recruit adaptor proteins to activate caspase-8 or -10. The inflammasome pathway activates caspase-1 (and related caspases) to process pro-inflammatory cytokines IL-1β and IL-18 and, in some contexts, to induce pyroptosis via gasdermin D cleavage.

Caspases have a broad range of substrates, including PARP, ICAD, lamins, and various signaling proteins, linking apoptotic and inflammatory outcomes to disease states. Dysregulation of caspases is implicated in cancer, neurodegenerative disorders, and autoinflammatory conditions. Therapeutic approaches include caspase inhibitors, though clinical development faces challenges due to redundancy and essential physiological roles.