HP1alpha:Histone H3 methylated at K9 Histone H3 methylated at lysine-9 HP1 alpha binds Histone H3K9(me)3 Authored: Akkerman, JW, 2010-10-29 Chromobox (CBX) genes encode members of the Heterochromatin Protein (HP) family. HP1 was discovered in Drosophila as a dominant suppressor of position-effect variegation and a major component of heterochromatin. The HP1 family is evolutionarily conserved, with members in fungi, plants and animals. Most animal species have several HP1 isoforms; humans have HP alpha, beta and gamme encoded by the genes CBX5, CBX1 and CBX3 respectively. <br>The HP1 amino-terminal chromodomain binds methylated lysine-9 of histone H3, causing transcriptional repression (Lachner et al. 2001). A crystal structure of human HP1 alpha in complex with H3K9(me)3 peptide is available (Amaya et al. 2008). The highly-conserved carboxy-terminal chromoshadow domain enables dimerization and also serves as a docking site for proteins involved in a wide variety of nuclear functions, from transcription to nuclear architecture.<br> Edited: Jupe, S, 2010-11-12 Pubmed11242053 Pubmed17224041 Reactome Database ID Release 43994106 Reactome, http://www.reactome.org ReactomeREACT_25059 Reviewed: Ouwehand, WH, 2010-11-12