CD-NTase

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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Structure and Mechanism of a Cyclic Trinucleotide-Activated Bacterial Endonuclease Mediating Bacteriophage Immunity

Anonymous — Mon, 06 Jan 2020 07:00:00 +0000

Structure and Mechanism of a Cyclic Trinucleotide-Activated Bacterial Endonuclease Mediating Bacteriophage Immunity Anonymous (not verified) Mon, 01/06/2020 - 00:00

Lau RK , Ye Q , Birkholz EA , Berg KR , Patel L , Mathews IT , Watrous JD , Ego K , ➤Whiteley AT , Lowey B , Mekalanos JJ , Kranzusch PJ , Jain M , Pogliano J , Corbett KD

Mol Cell. 2020 Jan 6. pii: S1097-2765(19)30923-2. doi: 10.1016/j.molcel.2019.12.010. [Epub ahead of print]

Abstract

Bacteria possess an array of defenses against foreign invaders, including a broadly distributed bacteriophage defense system termed CBASS (cyclic oligonucleotide-based anti-phage signaling system). In CBASS systems, a cGAS/DncV-like nucleotidyltransferase synthesizes cyclic di- or tri-nucleotide second messengers in response to infection, and these molecules activate diverse effectors to mediate bacteriophage immunity via abortive infection. Here, we show that the CBASS effector NucC is related to restriction enzymes but uniquely assembles into a homotrimer. Binding of NucC trimers to a cyclic tri-adenylate second messenger promotes assembly of a NucC homohexamer competent for non-specific double-strand DNA cleavage. In infected cells, NucC activation leads to complete destruction of the bacterial chromosome, causing cell death prior to completion of phage replication. In addition to CBASS systems, we identify NucC homologs in over 30 type III CRISPR/Cas systems, where they likely function as accessory nucleases activated by cyclic oligoadenylate second messengers synthesized by these systems' effector complexes.

Keywords:

CD-NTase; Endonuclease; abortive infection; bacteriophage immunity; second messenger signaling

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Bacterial cGAS-like enzymes synthesize diverse nucleotide signals

Anonymous — Fri, 01 Mar 2019 07:00:00 +0000

Bacterial cGAS-like enzymes synthesize diverse nucleotide signals Anonymous (not verified) Fri, 03/01/2019 - 00:00

➤Whiteley AT , Eaglesham JB , de Oliveira Mann CC , Morehouse BR , Lowey B , Nieminen EA , Danilchanka O , King DS , Lee ASY , Mekalanos JJ* , Kranzusch PJ*

*co-corresponding authors

Nature. 2019 Mar;567(7747):194-199. doi: 10.1038/s41586-019-0953-5. Epub 2019 Feb 20.

Abstract

Cyclic dinucleotides (CDNs) have central roles in bacterial homeostasis and virulence by acting as nucleotide second messengers. Bacterial CDNs also elicit immune responses during infection when they are detected by pattern-recognition receptors in animal cells. Here we perform a systematic biochemical screen for bacterial signalling nucleotides and discover a large family of cGAS/DncV-like nucleotidyltransferases (CD-NTases) that use both purine and pyrimidine nucleotides to synthesize a diverse range of CDNs. A series of crystal structures establish CD-NTases as a structurally conserved family and reveal key contacts in the enzyme active-site lid that direct purine or pyrimidine selection. CD-NTase products are not restricted to CDNs and also include an unexpected class of cyclic trinucleotide compounds. Biochemical and cellular analyses of CD-NTase signalling nucleotides demonstrate that these cyclic di- and trinucleotides activate distinct host receptors and thus may modulate the interaction of both pathogens and commensal microbiota with their animal and plant hosts.

News and Commentaries

Pyrimidines and Cyclic Trinucleotides Join the Second Messenger Symphony. [Cell host & microbe 2019]
Diverse bacterial nucleotide signals. [Science Signaling 2019]
Highlighted and discussed in This Week In Microbiology Podcast Episode #206

Links

➤Whiteley AT, Eaglesham JB, de Oliveira Mann CC, Morehouse BR, Lowey B, Nieminen EA, Danilchanka O, King DS, Lee ASY, Mekalanos JJ*, Kranzusch PJ* | Nature. 2019

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