Lysosomal endonuclease RNase T2 and PLD exonucleases cooperatively generate RNA ligands for TLR7 activation.
Immunity
; 57(7): 1482-1496.e8, 2024 Jul 09.
Article
em En
| MEDLINE
| ID: mdl-38697119
ABSTRACT
Toll-like receptor 7 (TLR7) is essential for recognition of RNA viruses and initiation of antiviral immunity. TLR7 contains two ligand-binding pockets that recognize different RNA degradation products pocket 1 recognizes guanosine, while pocket 2 coordinates pyrimidine-rich RNA fragments. We found that the endonuclease RNase T2, along with 5' exonucleases PLD3 and PLD4, collaboratively generate the ligands for TLR7. Specifically, RNase T2 generated guanosine 2',3'-cyclic monophosphate-terminated RNA fragments. PLD exonuclease activity further released the terminal 2',3'-cyclic guanosine monophosphate (2',3'-cGMP) to engage pocket 1 and was also needed to generate RNA fragments for pocket 2. Loss-of-function studies in cell lines and primary cells confirmed the critical requirement for PLD activity. Biochemical and structural studies showed that PLD enzymes form homodimers with two ligand-binding sites important for activity. Previously identified disease-associated PLD mutants failed to form stable dimers. Together, our data provide a mechanistic basis for the detection of RNA fragments by TLR7.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Endorribonucleases
/
Receptor 7 Toll-Like
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Immunity
Assunto da revista:
ALERGIA E IMUNOLOGIA
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Alemanha