Csx28 is a membrane pore that enhances CRISPR-Cas13b-dependent antiphage defense.
Science
; 380(6643): 410-415, 2023 04 28.
Article
in En
| MEDLINE
| ID: mdl-37104586
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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Proteins
/
Bacteriophages
/
RNA, Viral
/
Prevotella
/
Endodeoxyribonucleases
/
RNA Cleavage
/
CRISPR-Associated Proteins
/
CRISPR-Cas Systems
Language:
En
Journal:
Science
Year:
2023
Document type:
Article
Affiliation country:
United States