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Cad1 turns ATP into phage poison

Jinzhong Lin1, Yuvaraj Bhoobalan-Chitty2, Xu Peng1

  • 1Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Copenhagen, Denmark.

Cell Host & Microbe
|January 9, 2025
PubMed

Insights

A novel CRISPR-Cas effector, Cad1, was discovered. This enzyme halts phage propagation by converting ATP to ITP, causing host cell growth arrest.

Area of Science:

  • Molecular Biology
  • Microbial Genetics
  • Bacteriophage Research

Background:

  • Type III CRISPR-Cas systems provide robust anti-phage immunity.
  • CRISPR-Cas effectors include nucleases and membrane-destabilizing proteins.
  • The full repertoire of anti-phage mechanisms is not completely understood.

Purpose of the Study:

  • To identify and characterize novel effectors involved in the Type III CRISPR-Cas anti-phage response.
  • To elucidate the mechanism of action of the newly identified effector Cad1.
  • To understand how Cad1 contributes to inhibiting phage propagation.

Main Methods:

  • Biochemical assays to study Cad1 enzymatic activity.
  • Analysis of ITP accumulation in bacterial hosts.
  • Bacterial growth assays under phage infection.
  • Genetic manipulation of CRISPR-Cas system components.

Main Results:

  • Identification of Cad1 as an accessory effector in Type III CRISPR-Cas systems.
  • Demonstration that Cad1 deaminates ATP to inosine triphosphate (ITP).
  • Observation of ITP accumulation leading to host growth arrest.
  • Confirmation that Cad1 activity inhibits phage propagation.

Conclusions:

  • Cad1 represents a new class of CRISPR-Cas effector.
  • ITP accumulation is a mechanism for anti-phage defense.
  • The discovery of Cad1 expands our understanding of CRISPR-Cas immunity.

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