Download MendeleyCsx28 is a membrane pore that enhances CRISPR-Cas13b-dependent antiphage defense.
VanderWal, A.R., Park, J.U., Polevoda, B., Nicosia, J.K., Molina Vargas, A.M., Kellogg, E.H., O'Connell, M.R.(2023) Science 380: 410-415
- PubMed: 37104586
- DOI: https://doi.org/10.1126/science.abm1184
- Primary Citation of Related Structures:
8GI1 - PubMed Abstract:
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. These Csx28 pores localize to the inner membrane in vivo. Csx28's antiviral activity in vivo requires sequence-specific cleavage of viral messenger RNAs by Cas13b, which subsequently results in membrane depolarization, slowed metabolism, and inhibition of sustained viral infection. Our work suggests a mechanism by which Csx28 acts as a downstream, Cas13b-dependent effector protein that uses membrane perturbation as an antiviral defense strategy.
Organizational Affiliation:
Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.
