A virus protein uses host enolase to block type III CRISPR immune defense

AcrIIIA2, a newly discovered anti-CRISPR protein, forms a complex with host enolase to inhibit type III-A CRISPR immune responses.

• Phages can evade CRISPR immunity using anti-CRISPR proteins, with limited effectiveness observed in known type III Acrs.
• AcrIIIA2, found in Streptococcus thermophilus phages, interacts with host enolase, a key enzyme in glycolysis.
• This interaction creates a ternary complex that obstructs the binding of phage RNA to the type III-A CRISPR system.
• Blocking RNA binding prevents the activation of downstream immune responses against phages.
• Enolase acts as a structural scaffold, stabilizing the interactions between AcrIIIA2 and the CRISPR complex.

Simplified