DPP9's Enzymatic Activity and Not Its Binding to CARD8 Inhibits Inflammasome Activation
DPP9's Enzymatic Activity and Not Its Binding to CARD8 Inhibits Inflammasome Activation
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DOI：
10.1021/acschembio.9b00462
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发表时间：
2019-11-01
影响因子：
4
通讯作者：
Bachovchin, Daniel A.
中科院分区：
文献类型：
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作者：
Griswold, Andrew R.;Ball, Daniel P.;Bachovchin, Daniel A.
炎性小体是响应病原体而形成的多蛋白复合物。NLRP 1和CARD 8是形成炎性小体的相关蛋白，但病原体相关信号和控制其活化的分子机制尚未建立。丝氨酸二肽基肽酶DPP 8和DPP 9（DPP 8/9）的抑制剂激活NLRP 1和CARD 8。有趣的是，DPP 9直接与NLRP 1和NLRP 3结合，这种相互作用可能有助于抑制NLRP 1。在这里，我们使用基于活性的探针，重组炎性小体测定和基于质谱的蛋白质组学来进一步研究DPP 9-CARD 8相互作用。我们表明，。与DPP 9-NLRP 1相互作用不同，DPP 9-CARD 8相互作用不会被阻断自身蛋白水解的DPP 9抑制剂或CARD 8突变破坏。此外，野生型但非无催化活性的突变体DPP 9在DPP 9敲除细胞中挽救CARD 8介导的细胞死亡。总之，这项工作揭示了DPP 9的催化活性而不是其与CARD 8的结合抑制了炎症小体，因此表明结合相互作用可能服务于其他生物学目的。
Inflammasomes are multiprotein complexes formed in response to pathogens. NLRP1 and CARD8 are related proteins that form inflammasomes, but the pathogen-associated signal(s) and the molecular mechanisms controlling their activation have not been established. Inhibitors of the serine dipeptidyl peptidases DPP8 and DPP9 (DPP8/9) activate both NLRP1 and CARD8. Interestingly, DPP9 binds directly to NLRP1 and CARDS, and this interaction may contribute to the inhibition of NLRP1. Here, we use activity-based probes, reconstituted inflammasome assays, and mass spectrometry-based proteomics to further investigate the DPP9-CARD8 interaction. We show that the. DPP9-CARD8 interaction, unlike the DPP9-NLRP1 interaction, is not disrupted by DPP9 inhibitors or CARD8 mutations that block autoproteolysis. Moreover, wild-type, but not catalytically inactive mutant, DPP9 rescues CARD8-mediated cell death in DPP9 knockout cells. Together, this work reveals that DPP9's catalytic activity and not its binding to CARD8 restrains the CARDS inflammasome and thus suggests the binding interaction likely serves some other biological purpose.