Table I.
Molecules involved in PCD
| Molecule name | Abbreviation | Pathway | Function |
|---|---|---|---|
| Absent in melanoma 2 | AIM2 | Pyroptosis | Pattern recognition receptor that starts the pyroptosis cascade |
| Apoptotic protease activating factor 1 | APAF1 | Apoptosis (intrinsic) | Activator of procaspase-9 |
| Apoptosis-associated speck-like protein containing a caspase recruitment domain | ASC | Pyroptosis | Recruits procaspase-1 to the inflammasome |
| Caspase-1 | CASP1 | Pyroptosis | Cleaves GSDMD |
| Caspase-3 | CASP3 | Apoptosis | Executioner caspase that triggers apoptosis |
| Caspase-8 | CASP8 | Apoptosis (extrinsic), necroptosis | Initiator caspase of the extrinsic apoptosis pathway; activates procaspase-3; its presence inhibits necroptosis |
| Caspase-9 | CASP9 | Apoptosis (intrinsic) | Initiator caspase of intrinsic apoptosis pathway; activates procaspase-3 |
| Cellular inhibitor of apoptosis protein 1 | cIAP1 | Apoptosis (extrinsic), necroptosis | Ubiquitinates caspase-8, allowing necroptosis to proceed |
| Cellular inhibitor of apoptosis protein 2 | cIAP2 | Apoptosis (extrinsic), necroptosis | Ubiquitinates caspase-8, allowing necroptosis to proceed |
| Cylindromatosis | CYLD | Apoptosis (extrinsic), necroptosis | Deubiquitinates caspase-8 to inhibit necroptosis |
| Fas-associated via death domain | FADD | Apoptosis (extrinsic), necroptosis | Recruits procaspase-8 |
| Fas ligand | Fas-L | Apoptosis (extrinsic), necroptosis | Binds death receptor to initiate extrinsic apoptosis or necroptosis |
| Gasdermin D | GSDMD | Pyroptosis | Perforates cell membrane to allow release of IL-1β and IL-18 |
| Mixed-lineage kinase domain like | MLKL | Necroptosis | Final executor of necroptosis; permeabilizes cell membrane |
| Receptor-interacting serine/threonine-protein kinase 1 | RIPK1 | Apoptosis (extrinsic), necroptosis | Recruits RIPK3; can form apoptotic complex |
| Receptor-interacting serine/threonine-protein kinase 3 | RIPK3 | Necroptosis | Activates MLKL |
| TNF-α | TNF-α | Apoptosis (extrinsic), necroptosis | Binds death receptors to trigger extrinsic apoptosis or necroptosis |
| TNF receptor 1 | TNFR1 | Apoptosis (extrinsic), necroptosis | Activated by TNF-α to initiate extrinsic apoptosis or necroptosis |
| TNF receptor–associated factor | TRAF | Apoptosis (extrinsic), necroptosis | Ubiquitinates caspase-8, allowing necroptosis to proceed |
| TNF receptor superfamily member 1A–associated via death domain | TRADD | Necroptosis | Recruits procaspase-8 |