Laboratory of Microbiology, Wageningen University and Research, Wageningen, Netherlands.
Scope Biosciences B.V., Wageningen, Netherlands.
Science. 2024 Feb 2;383(6682):512-519. doi: 10.1126/science.adk0378. Epub 2024 Feb 1.
The generation of cyclic oligoadenylates and subsequent allosteric activation of proteins that carry sensory domains is a distinctive feature of type III CRISPR-Cas systems. In this work, we characterize a set of associated genes of a type III-B system from that contains two caspase-like proteases, SAVED-CHAT and PCaspase (prokaryotic caspase), co-opted from a cyclic oligonucleotide-based antiphage signaling system (CBASS). Cyclic tri-adenosine monophosphate (AMP)-induced oligomerization of SAVED-CHAT activates proteolytic activity of the CHAT domains, which specifically cleave and activate PCaspase. Subsequently, activated PCaspase cleaves a multitude of proteins, which results in a strong interference phenotype in vivo in Taken together, our findings reveal how a CRISPR-Cas-based detection of a target RNA triggers a cascade of caspase-associated proteolytic activities.
环状寡聚腺苷酸的产生和随后对携带感应结构域的蛋白质的变构激活是 III 型 CRISPR-Cas 系统的一个显著特征。在这项工作中,我们对来自的 III-B 型系统的一组相关基因进行了表征,该系统包含两个半胱氨酸蛋白酶样蛋白酶,SAVED-CHAT 和 PCaspase(原核半胱氨酸蛋白酶),它们来自基于环状寡核苷酸的抗噬菌体信号系统(CBASS)。环状三腺苷一磷酸(AMP)诱导的 SAVED-CHAT 寡聚化激活了 CHAT 结构域的蛋白水解活性,该活性特异性切割并激活 PCaspase。随后,激活的 PCaspase 切割多种蛋白质,导致在体内产生强烈的干扰表型。总之,我们的发现揭示了基于 CRISPR-Cas 的靶 RNA 检测如何触发一连串与 Caspase 相关的蛋白水解活性。