The linguistics of bacterial conflict systems reveal ancient origins of eukaryotic innate immunity

Anonymous — Thu, 19 Nov 2020 15:00:00 +0000

The linguistics of bacterial conflict systems reveal ancient origins of eukaryotic innate immunity Anonymous (not verified) Thu, 11/19/2020 - 08:00

Emily Kibby Aaron Whiteley

J. Bacteriology 2020 Nov 19;202(24):e00507-20. doi: 10.1128/JB.00507-20. Online ahead of print.

Abstract

The arms-race between bacteria and their competitors has produced an astounding variety of conflict systems that are shared via horizontal gene transfer across bacterial populations. In this issue of Journal of Bacteriology, Burroughs and Aravind investigate how these biological conflict systems have been mixed-and-matched into new configurations, often with novel protein domains. The authors additionally characterize the evolutionary history of genes in eukaryotes that appear to have been acquired from these prokaryotic defense systems.

CBASS Immunity Uses CARF-Related Effectors to Sense 3'-5'- and 2'-5'-Linked Cyclic Oligonucleotide Signals and Protect Bacteria from Phage Infection

Anonymous — Thu, 09 Jul 2020 15:00:00 +0000

CBASS Immunity Uses CARF-Related Effectors to Sense 3'-5'- and 2'-5'-Linked Cyclic Oligonucleotide Signals and Protect Bacteria from Phage Infection Anonymous (not verified) Thu, 07/09/2020 - 09:00

Lowey B ➤Whiteley AT Keszei AFA Morehouse BR Mathews IT Antine SP Cabrera VJ Kashin D Niemann P Jain M Schwede F Mekalanos JJ Shao S Lee ASY Kranzusch PJ

Cell. 2020 Jul 9;182(1):38-49.e17. doi: 10.1016/j.cell.2020.05.019. Epub 2020 Jun 15.

Abstract

cGAS/DncV-like nucleotidyltransferase (CD-NTase) enzymes are immune sensors that synthesize nucleotide second messengers and initiate antiviral responses in bacterial and animal cells. Here, we discover Enterobacter cloacae CD-NTase-associated protein 4 (Cap4) as a founding member of a diverse family of >2,000 bacterial receptors that respond to CD-NTase signals. Structures of Cap4 reveal a promiscuous DNA endonuclease domain activated through ligand-induced oligomerization. Oligonucleotide recognition occurs through an appended SAVED domain that is an unexpected fusion of two CRISPR-associated Rossman fold (CARF) subunits co-opted from type III CRISPR immunity. Like a lock and key, SAVED effectors exquisitely discriminate 2'-5'- and 3'-5'-linked bacterial cyclicoligonucleotide signals and enable specific recognition of at least 180 potential nucleotide second messenger species. Our results reveal SAVED CARF family proteins as major nucleotide second messenger receptors in CBASS and CRISPR immune defense and extend the importance of linkage specificity beyond mammalian cGAS-STING signaling.

Keywords:

CARF; CBASS antiphage immunity; CD-NTase; SAVED; nucleotide second messenger

Links

PMID: 32544385

DOI: 10.1016/j.cell.2020.05.019

Lowey B, ➤Whiteley AT, Keszei AFA, Morehouse BR, Mathews IT, Antine SP, Cabrera VJ, Kashin D, Niemann P, Jain M, Schwede F, Mekalanos JJ, Shao S, Lee ASY, Kranzusch PJ. | Cell. 2020

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