Replication initiator 1 in adipose tissue function and human obesity.

Replication initiator 1 (Repin1) was discovered as the replication initiation-region protein 60kDa (RIP60) and characterized as a zinc finger protein involved in DNA binding and bending during initiation of DNA replication. As with many members of the zinc finger family, physiological functions and regulations of Repin1 as well as the underlying molecular mechanisms have remained elusive since its discovery in 1990. However, recent results have revealed interesting new insights into Repin1 function. Repin1 is highly expressed in liver and adipose tissue and it has been suggested as a candidate gene for obesity and related metabolic disorders in congenic and subcongenic rat strains. Repin1 seems to participate in the regulation of genes involved in adipogenesis, lipid droplet formation and fusion, as well as glucose and fatty acid transport in adipocytes. Given the observation that Repin1 expression in human adipose tissue significantly correlates with total body fat mass and adipocyte size, therapeutic strategies to reduce Repin1 action in adipose tissue may be a potential approach to tackle adipose tissue dysfunction in obesity. Thus, human and in vitro data suggest a role of Repin1 in adipocyte function and could therefore emerge as an interesting therapeutic target in human obesity.