6kn0
From Proteopedia
caspase-1 P20/P10 C285A in complex with human GSDMD-C domain
Structural highlights
Function[CASP1_HUMAN] Thiol protease that cleaves IL-1 beta between an Asp and an Ala, releasing the mature cytokine which is involved in a variety of inflammatory processes. Important for defense against pathogens. Cleaves and activates sterol regulatory element binding proteins (SREBPs). Can also promote apoptosis.[1] [2] [GSDMD_HUMAN] Gasdermin-D, N-terminal: Promotes pyroptosis in response to microbial infection and danger signals. Produced by the cleavage of gasdermin-D by inflammatory caspases CASP1 or CASP4 in response to canonical, as well as non-canonical (such as cytosolic LPS) inflammasome activators (PubMed:26375003, PubMed:26375259, PubMed:27418190). After cleavage, moves to the plasma membrane where it strongly binds to inner leaflet lipids, including monophosphorylated phosphatidylinositols, such as phosphatidylinositol 4-phosphate, bisphosphorylated phosphatidylinositols, such as phosphatidylinositol (4,5)-bisphosphate, as well as phosphatidylinositol (3,4,5)-bisphosphate, and more weakly to phosphatidic acid and phosphatidylserine (PubMed:27281216). Homooligomerizes within the membrane and forms pores of 10 - 15 nanometers (nm) of inner diameter, possibly allowing the release of mature IL1B and triggering pyroptosis (PubMed:27418190, PubMed:27281216). Exhibits bactericidal activity. Gasdermin-D, N-terminal released from pyroptotic cells into the extracellular milieu rapidly binds to and kills both Gram-negative and Gram-positive bacteria, without harming neighboring mammalian cells, as it does not disrupt the plasma membrane from the outside due to lipid-binding specificity (PubMed:27281216). Under cell culture conditions, also active against intracellular bacteria, such as Listeria monocytogenes (By similarity). Strongly binds to bacterial and mitochondrial lipids, including cardiolipin. Does not bind to unphosphorylated phosphatidylinositol, phosphatidylethanolamine nor phosphatidylcholine (PubMed:27281216).[UniProtKB:Q9D8T2][3] [4] [5] [6] Publication Abstract from PubMedThe pyroptosis execution protein GSDMD is cleaved by inflammasome-activated caspase-1 and LPS-activated caspase-11/4/5. The cleavage unmasks the pore-forming domain from GSDMD-C-terminal domain. How the caspases recognize GSDMD and its connection with caspase activation are unknown. Here, we show site-specific caspase-4/11 autoprocessing, generating a p10 product, is required and sufficient for cleaving GSDMD and inducing pyroptosis. The p10-form autoprocessed caspase-4/11 binds the GSDMD-C domain with a high affinity. Structural comparison of autoprocessed and unprocessed capase-11 identifies a beta sheet induced by the autoprocessing. In caspase-4/11-GSDMD-C complex crystal structures, the beta sheet organizes a hydrophobic GSDMD-binding interface that is only possible for p10-form caspase-4/11. The binding promotes dimerization-mediated caspase activation, rendering a cleavage independently of the cleavage-site tetrapeptide sequence. Crystal structure of caspase-1-GSDMD-C complex shows a similar GSDMD-recognition mode. Our study reveals an unprecedented substrate-targeting mechanism for caspases. The hydrophobic interface suggests an additional space for developing inhibitors specific for pyroptotic caspases. Structural Mechanism for GSDMD Targeting by Autoprocessed Caspases in Pyroptosis.,Wang K, Sun Q, Zhong X, Zeng M, Zeng H, Shi X, Li Z, Wang Y, Zhao Q, Shao F, Ding J Cell. 2020 Mar 5;180(5):941-955.e20. doi: 10.1016/j.cell.2020.02.002. Epub 2020, Feb 27. PMID:32109412[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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