We had recently discovered a new signalling cascade in type III CRISPR immune systems, the CalpLTS cascade. In a nutshell, the CalpL protease senses cyclic oligonucleotides that are produced by the type III recognition complex, cleaves the anti-sigma factor CalpT and thereby releases the sigma factor CalpS. In our new study we have discovered that the multi functional CalpL protein also has a ring nuclease activity that degrades the cyclic oligonucleotides. It thus acts as a molecular timer that attenuates the immune response. You can read all the interesting details here.
