Figure 1. LSD1, through histone 3 demethylation, has dual functions as both a transcriptional activator and repressor.

As an illustration of this, LSD1 (lysine-specific demethylase 1) can be associated with activated estrogen receptors (ERs) or androgen receptors (ARs) and promote demethylation at lysine 9 (K9) of the histone tail. This confers opening of heterochromatin, promoting transcriptional activation. Alternatively, LSD1 can complex with CoREST and histone deacetylase 1/2 (HDAC1/2). This association confers more specificity for methylated lysine 4 (K4), resulting in its demethylation. This promotes heterochromatin formation and transcriptional repression.