A transcriptionally active lipid vesicle encloses the injected genome in early infection.

Many eukaryotic viruses require membrane-bound compartments for replication, but no such organelles are known to be formed by prokaryotic viruses. Bacteriophages of the family sequester their genomes within a phage-generated organelle, the phage nucleus, which is enclosed by a lattice of the viral protein ChmA. Previously, we observed lipid membrane-bound vesicles in cells infected by , but due to the paucity of genetics tools for these viruses it was unknown if these vesicles represented unproductive, abortive infections or a stage in the phage life cycle.

Csx28 is a membrane pore that enhances CRISPR-Cas13b-dependent antiphage defense.

Type VI CRISPR-Cas systems use RNA-guided ribonuclease (RNase) Cas13 to defend bacteria against viruses, and some of these systems encode putative membrane proteins that have unclear roles in Cas13-mediated defense. We show that Csx28, of type VI-B2 systems, is a transmembrane protein that assists to slow cellular metabolism upon viral infection, increasing antiviral defense. High-resolution cryo-electron microscopy reveals that Csx28 forms an octameric pore-like structure.

Environmental pH and peptide signaling control virulence of Streptococcus pyogenes via a quorum-sensing pathway.

Bacteria control gene expression in concert with their population density by a process called quorum sensing, which is modulated by bacterial chemical signals and environmental factors. In the human pathogen Streptococcus pyogenes, production of secreted virulence factor SpeB is controlled by a quorum-sensing pathway and environmental pH. The quorum-sensing pathway consists of a secreted leaderless peptide signal (SIP), and its cognate receptor RopB.

Signaling by a Conserved Quorum Sensing Pathway Contributes to Growth and Oropharyngeal Colonization of Human Pathogen Group A Streptococcus.

Bacterial virulence factor production is a highly coordinated process. The temporal pattern of bacterial gene expression varies in different host anatomic sites to overcome niche-specific challenges. The human pathogen group A streptococcus (GAS) produces a potent secreted protease, SpeB, that is crucial for pathogenesis.

Leaderless secreted peptide signaling molecule alters global gene expression and increases virulence of a human bacterial pathogen.

Successful pathogens use complex signaling mechanisms to monitor their environment and reprogram global gene expression during specific stages of infection. Group A (GAS) is a major human pathogen that causes significant disease burden worldwide. A secreted cysteine protease known as streptococcal pyrogenic exotoxin B (SpeB) is a key virulence factor that is produced abundantly during infection and is critical for GAS pathogenesis.

Iron Efflux by PmtA Is Critical for Oxidative Stress Resistance and Contributes Significantly to Group A Streptococcus Virulence.

Group A (GAS) is a human-only pathogen that causes a spectrum of disease conditions. Given its survival in inflamed lesions, the ability to sense and overcome oxidative stress is critical for GAS pathogenesis. PerR senses oxidative stress and coordinates the regulation of genes involved in GAS antioxidant defenses.