Mind the methyl: methyllysine binding proteins in epigenetic regulation.

Epigenetics is defined as the phenomenon of heritable phenotypic traits that are not governed by alteration of the genetic code. Major epigenetic control mechanisms include DNA methylation and post-translational modifications of histones, such as reversible histone acetylation and methylation of lysine residues. Methyllysine binding proteins recognize various levels of lysine methylation and mediate the signaling events that are induced by histone methylation. Therefore, they are also referred to as readers of the epigenetic code. In this article we review the current literature on the structure and biology of methyllysine binding proteins, especially with regard to their potential as drug targets. We also present the available inhibitors that block the interaction of methylated histones with their binding proteins.