Rev-Erb A Alpha - Physiologic Function

Physiologic Function

Rev-erbα regulates gene transcription by directly binding to target response elements (RevREs), comprises an A/T-rich flank followed by AGGTCA. Rev-erbα mediates repression by recruiting the corepressor N-CoR, which then activates the histone deacetylase (HDAC) 3. A number of target genes has been identified for Rev-erbα, including the lipoproteins ApoA1 and ApoCIII, hydratase dehydrogenase, the circadian factor BMAL, and the anti-fibrinolytic factor PAI-1. Many of these genes are coordinately regulated by Rev-erbα and the RAR-related orphan receptor RORα, which share the same response elements but exert opposite effects on gene transcription. Crosstalk between Rev-erbα and RORα likely acts to fine-tune their target physiologic networks, such as circadian rhythms, metabolic homeostasis, and inflammation.

Rev-erbα mRNA is induced during adipogenesis and is highly expressed in adipose tissue. One study reported that overexpression of Rev-erbα may enhance adipogenesis in cultured mouse adipocytes, but the mechanism of this effect remains to be elucidated. More recently, a study showed that the deletion of Rev-erbα in mice alters glucose and lipid metabolism and leads to obesity.

Rev-erbα expression is also regulated at the post-translational level: it is phosphorylated on the amino terminus by glycogen synthase kinase (GSK 3β), which contributes to its protein stability. It has been shown that lithium, which inhibits GSK3β, can de-stabilize Rev-erbα protein and affect its function in the circadian clock. This may partly explain lithium’s therapeutic effect on circadian diseases such as bipolar disorder.