Abstract: For billions of years, bacteria have been locked in an evolutionary arms race with phages and other pathogenic elements like plasmids. This ongoing battle has driven the development of myriad bacterial defense systems and numerous phage-encoded counter-defense strategies. Over the last decade, more than a hundred distinct defense systems have been identified in bacteria. Interestingly, several of these newly discovered immune systems share evolutionary connections with components of our own innate immune system. Despite their identified protective activities against phages and plasmids, the precise molecular mechanisms governing these immune functions have remained unknown. Here, I will describe my recent research on the molecular and mechanistic understanding of the bacterial Wadjet (an anti-plasmid) and PARIS (an anti-phage) defense system, using an integrated approach combining structural biology, biochemistry, and microbiology tools. These works demonstrate how proteins from the same family, SMC-family ATPases, have evolved to recognize distinct molecular patterns and provide protection against invading plasmids and phages. More broadly, these findings highlight the power of the bacterial-pathogen arms race to evolve new functions from existing protein machinery and underscore the potential for discovery in studying these defense systems’ molecular mechanisms.

Meeting ID: 990 3614 9298
Passcode: 825362