T cell activation triggers reversible inosine-5'-monophosphate dehydrogenase assembly.
J Cell Sci
; 131(17)2018 09 05.
Article
em En
| MEDLINE
| ID: mdl-30154209
ABSTRACT
T cell-mediated adaptive immunity requires naïve, unstimulated T cells to transition from a quiescent metabolic state into a highly proliferative state upon T cell receptor engagement. This complex process depends on transcriptional changes mediated by Ca2+-dependent NFAT signaling, mTOR-mediated signaling and increased activity of the guanine nucleotide biosynthetic inosine-5'-monophosphate (IMP) dehydrogenase 1 and 2 enzymes (IMPDH1 and IMPDH2, hereafter IMPDH). Inhibitors of these pathways serve as potent immunosuppressants. Unexpectedly, we discovered that all three pathways converge to promote the assembly of IMPDH protein into micron-scale macromolecular filamentous structures in response to T cell activation. Assembly is post-transcriptionally controlled by mTOR and the Ca2+ influx regulator STIM1. Furthermore, IMPDH assembly and catalytic activity were negatively regulated by guanine nucleotide levels, suggesting a negative feedback loop that limits biosynthesis of guanine nucleotides. Filamentous IMPDH may be more resistant to this inhibition, facilitating accumulation of the higher GTP levels required for T cell proliferation.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Linfócitos T
/
IMP Desidrogenase
Limite:
Animals
Idioma:
En
Revista:
J Cell Sci
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Estados Unidos