ADARs: allies or enemies? The importance of A-to-I RNA editing in human disease: from cancer to HIV-1

Adenosine deaminases acting on RNA (ADARs) are enzymes that convert adenosine (A) to inosine (I) in nuclear-encoded RNAs and viral RNAs. The activity of ADARs has been demonstrated to be essential in mammals and serves to fine-tune different proteins and modulate many molecular pathways. Recent findings have shown that ADAR activity is altered in many pathological tissues. Moreover, it has been shown that modulation of RNA editing is important for cell proliferation and migration, and has a protective effect on ischaemic insults. This review summarises available recent knowledge on A-to-I RNA editing and ADAR enzymes, with particular attention given to the emerging role played by these enzymes in cancer, some infectious diseases and immune-mediated disorders.