In a recent paper published in Nature,Jenson et al.[1]reported that CD-NTases-associated protein 2(Cap2)regulates the activity of bacterial cyclic GMP-AMP synthase(cGAS)-like enzymes in a manner analogous to ubiquitination,boosting the production of the second messenger cyclic GMP-AMP(cGAMP)to enable antiphage immunity.The ubiquitin-like conjugation system serves as a countermeasure to phage evasion strategy that sequesters cGAMP to block downstream phospholipase activation,thereby enhancing bacterial defense(Fig.1)[1].This discovery not only unveils a primitive defense mechanism by modulating bacterial cGAS antiviral activity but also represents a compelling example of the escalating arms race between bacteria and phages,which deepens our insight into viral tactics how to evade cGAS-based host defenses.
