Biology subjects

Hadary, R.

Publications and source records attributed to Hadary, R..

3 recordsLinked to original sources

bioRxiv2026

Phage RyR-domain proteins degrade ADPR-based immune signals and fuel NAD synthesis

Bacterial, plant, and animal cells synthesize nucleotide immune signals as a conserved strategy to defend against viral infection1-4. In bacteria, Thoeris anti-phage defense systems convert nicotinamide adenine dinucleotide (NAD+) into the cyclic ADP-ribose signals 2'cADPR and 3'cADPR to activate downstream effectors and restrict viral replication5-8. Phage proteins can bind and sequester Thoeris signals6,9-13, but no mechanisms are known to degrade the exceptionally stable 2'cADPR and 3'cADPR molecules and terminate immune activation. Here we use a forward biochemical screen to discover the mycobacteriophage protein RyDEP as the founding member of an enzyme family that cleaves 2'cADPR and 3'cADPR to inactivate Thoeris defense. We show that RyDEP is a glycosidase that cleaves the ribose-ribose linkage in 2' and 3' cADPR immune signals to both inactivate host defense and enable direct restoration of NAD+. A crystal structure of the RyDEP-3'cADPR complex in the post-cleavage state explains the molecular basis of immune signal degradation and reveals surprising homology with the Repeat12 domain of animal ryanodine receptors (RyRs) that control calcium flux and muscle contraction14,15. We demonstrate that diverse phage RyDEP proteins tune RyR-domain activity to either degrade or sequester immune signals. Our results define RyR-domain proteins as regulators of nucleotide immune signaling and explain how viruses subvert host antiviral defense.

microbiology↗

bioRxiv2025

Functional diversity of phage sponge proteins that sequester host immune signals

Multiple bacterial immune systems, including CBASS, Thoeris, and Pycsar, employ signaling molecules that activate the immune response following phage infection. Phages counteract bacterial immune signaling using sponge proteins that bind and sequester the immune signals, but the breadth of immune signals targeted by phage sponges is unclear. Here we study the functional versatility of Acb2, Tad1 and Tad2, three families of sponge proteins known to inhibit CBASS and Thoeris signaling. Eighty-four proteins representing the phylogenetic diversity of these sponge families were tested for their ability to inhibit immunity by sequestering 3'3'-cGAMP and 3'3'-cUA (CBASS), cCMP and cUMP (Pycsar), and 3'cADPR, His-ADPR and N7-cADPR (types I, II and IV Thoeris, respectively). While Acb2 proteins were so far reported to inhibit only CBASS systems, we found Acb2 homologs that bind 3'cADPR and inhibit Thoeris defense. In addition, we discovered sponge proteins that inhibit Pycsar and type IV Thoeris by binding cUMP and N7-cADPR, respectively. Using crystal structures, structural modeling and biochemical analyses, we explain the molecular basis for signal-binding specificities in members of these sponge families. Our study reports the first sponges inhibiting Pycsar and type IV Thoeris, and demonstrates how phage sponges evolve to obtain diverse specificities.

microbiology↗

bioRxiv2023

CARD-like domains mediate anti-phage defense in bacterial gasdermin systems

Caspase recruitment domains (CARDs) and pyrin domains are important facilitators of inflammasome activity and pyroptosis. Upon pathogen recognition by NLR proteins, CARDs recruit and activate caspases, which, in turn, activate gasdermin pore forming proteins to and induce pyroptotic cell death. Here we show that CARD-like domains are present in defense systems that protect bacteria against phage. The bacterial CARD is essential for protease-mediated activation of certain bacterial gasdermins, which promote cell death once phage infection is recognized. We further show that multiple anti-phage defense systems utilize CARD-like domains to activate a variety of cell death effectors. We find that these systems are triggered by a conserved immune evasion protein that phages use to overcome the bacterial defense system RexAB, demonstrating that phage proteins inhibiting one defense system can activate another. We also detect a phage protein with a predicted CARD-like structure that can inhibit the CARD-containing bacterial gasdermin system. Our results suggest that CARD domains represent an ancient component of innate immune systems conserved from bacteria to humans, and that CARD-dependent activation of gasdermins is conserved in organisms across the tree of life.

microbiology↗