The recent discovery of ubiquitination systems in bacteria is revolutionizing our understanding of antiviral defense mechanisms. Although ubiquitination has long been recognized as a central process in eukaryotes, its role in prokaryotes remains largely unexplored.

During this seminar, David Mayo Muñoz will present his research showing how a non-canonical bacterial ubiquitination pathway protects bacteria against a wide variety of bacteriophages. By covalently modifying the lateral fibers of phages, this system disrupts virion assembly and prevents their spread within the bacterial population. These findings reveal a novel antiviral mechanism and highlight a defense strategy that has been surprisingly well-conserved throughout evolution.

A bacterial ubiquitination pathway modifies bacteriophages to prevent viral spread throughout the population

Ubiquitination is a central regulatory mechanism in eukaryotic cell biology, governing processes ranging from protein turnover to antiviral defense. In bacteria, the conjugation of ubiquitin-like proteins is emerging as a core function of diverse anti-phage defenses, including systems with evolutionary links to the human antiviral ISG15 pathway. Recent research has uncovered a divergent bacterial ubiquitination system with altered conjugation chemistry, but its biological function has remained unclear. Here, we show that this non-canonical ubiquitination pathway provides robust defense against a diverse range of bacteriophages. Combining genetic, bioinformatic, and biochemical analyses, we demonstrate that ubiquitin modification of phage lateral tail fibers impairs virion assembly, thereby preventing viral spread throughout the population. Together, our findings establish the immune function of a divergent ubiquitination pathway and reveal that covalent remodeling of viral structural proteins is a conserved antiviral strategy employed across diverse ubiquitination systems and domains of life.

Speaker

🎤 David Mayo Muñoz, Ph.D.
Postdoctoral Fellow, Department of Microbiology
Department of Biology, University of Copenhagen (Denmark)

Invitation from Dr. Frédérique Le Roux