Dalia Smalakyte, Audrone Ruksenaite, Giedrius Sasnauskas, Giedre Tamulaitiene, Gintautas Tamulaitis
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引用次数: 0
Abstract
To combat phage infection, type III CRISPR-Cas systems utilize cyclic oligoadenylates (cAn) signaling to activate various auxiliary effectors, including the CRISPR-associated Lon-SAVED protease CalpL, which forms a tripartite effector system together with an anti-σ factor, CalpT, and an ECF-like σ factor, CalpS. Here, we report the characterization of the Candidatus Cloacimonas acidaminovorans CalpL-CalpT-CalpS. We demonstrate that cA4 binding triggers CalpL filament formation and activates it to cleave CalpT within the CalpT-CalpS dimer. This cleavage exposes the CalpT C-degron, which targets it for further degradation by cellular proteases. Consequently, CalpS is released to bind to RNA polymerase, causing growth arrest in E. coli. Furthermore, the CalpL-CalpT-CalpS system is regulated by the SAVED domain of CalpL, which is a ring nuclease that cleaves cA4 in a sequential three-step mechanism. These findings provide key mechanistic details for the activation, proteolytic events, and regulation of the signaling cascade in the type III CRISPR-Cas immunity.
期刊介绍:
Molecular Cell is a companion to Cell, the leading journal of biology and the highest-impact journal in the world. Launched in December 1997 and published monthly. Molecular Cell is dedicated to publishing cutting-edge research in molecular biology, focusing on fundamental cellular processes. The journal encompasses a wide range of topics, including DNA replication, recombination, and repair; Chromatin biology and genome organization; Transcription; RNA processing and decay; Non-coding RNA function; Translation; Protein folding, modification, and quality control; Signal transduction pathways; Cell cycle and checkpoints; Cell death; Autophagy; Metabolism.