IRG1 Flashcards
When is immunoresponsive gene 1 (IRG1) expressed and where?
IRG1 expression is rapidly induced within macrophage-lineage cells in response to live bacterial challenge and TLR agonist stimulation.
What is the function of immunoresponsive gene 1 (IRG1)?
IRG1 localises to mitochondria and functions during catabolism of the short-chain fatty acid propionate.
What does C/EBPB do?
The primary-responsive transcription factor C/EBPB helps drive infection-responsive irg1 expression within macrophage lineage-cells.
What is CHX and how does it affect C/EBP? Is C/EBP controlled?
CHX is a protein synthesis inhibition protein that enhances C/EBP expression in infected zebrafish larvae and control larvae. C/EBP is possibly controlled by a transcriptional repressor.
What is the effect of glucocorticoid receptor (GR) agonists on C/EBPB and IRG1?
Stimulation with GR agonists is sufficient to activate C/EBPB, but not IRG1.
How does STAT3 function in the IRG1 signalling cascade?
Activation of STAT3 is crucial for inducing IRG1. Inhibition of JAK/STAT signalling abolishes IRG1 expression during inflammatory responses. However, STAT3 depletion does not affect the expression of C/EBPB.
Which pathways regulate IRG1 expression?
The C/EBPB, GR, and JAK/STAT signalling pathways.
What happens to mitochondria that lack IRG1?
Mitochondria of IRG1-depleted macrophage-lineage cells are deficient in their ability to utilise fatty acids as an energy substrate for mitochondrial oxidative phosphorilation and mitochondrial ROS (mROS) production, resulting in decreased bactericidal activity.
Where does ROS production take place, and when?
ROS production is localised in the mitochondria in response to infection.
What is a requirement for IRG1-dependent mROS production?
IRG1-dependent mROS production requires fatty acid B-oxidation.
Which effect does IRG1-depletion have on persistence of bacterial infection?
IRG-depleted larvae present increased persistence of Salmonella.
