Fig. 2
From: Emerging role of the RNA-editing enzyme ADAR1 in stem cell fate and function
(A) The role of ADAR1 in miRNA production and the immune response. ADAR1 editing of mRNA does not activate downstream pathways under normal conditions; however, when it is absent, it causes activation of the MDA5 and PKR pathways, leading to apoptosis. ADAR1 can not only inhibit miRNA production but also alter its targeting to cause changes in target genes. In addition, ADAR1 can promote the production of miRNAs by forming complexes. (B) Molecular functions of ADAR1 in regulating stem cells and aging. ADAR1 affects stem cell function and cell fate through three pathways. The pathways include affecting senescence, immune response and miRNA production. In addition, the cells regulate ADAR1 through autophagy, which leads to the decline of SIRT1 mRNA stability and up-regulation of downstream p16 protein expression, and finally cause cell aging