HP1 binds specifically to Lys26-methylated histone H1.4, whereas simultaneous Ser27 phosphorylation blocks HP1 binding.
Fiche publication
Date publication
novembre 2005
Journal
The Journal of biological chemistry
Auteurs
Membres identifiés du Cancéropôle Est :
Dr DAUJAT Sylvain
Tous les auteurs :
Daujat S, Zeissler U, Waldmann T, Happel N, Schneider R
Lien Pubmed
Résumé
Histone lysine methylation can have positive or negative effects on transcription, depending on the precise methylation site. According to the "histone code" hypothesis these methylation marks can be read by proteins that bind them specifically and then regulate downstream events. Hetero-chromatin protein 1 (HP1), an essential component of heterochromatin, binds specifically to methylated Lys(9) of histone H3 (K9/H3). The linker histone H1.4 is methylated on Lys(26) (K26/H1.4), but the role of this methylation in downstream events remains unknown. Here we identify HP1 as a protein specifically recognizing and binding to methylated K26/H1.4. We demonstrate that the Chromo domain of HP1 is mediating this binding and that phosphorylation of Ser(27) on H1.4 (S27/H1.4) prevents HP1 from binding. We suggest that methylation of K26/H1.4 could have a role in tethering HP1 to chromatin and that this could also explain how HP1 is targeted to those regions of chromatin where it does not colocalize with methylated K9/H3. Our results provide the first experimental evidence for a "phospho switch" model in which neighboring phosphorylation reverts the effect of histone lysine methylation.
Mots clés
Animals, Cell Nucleus, Chromosomal Proteins, Non-Histone, genetics, HeLa Cells, Histones, chemistry, Humans, Lysine, metabolism, Methylation, Mice, Phosphorylation, Phosphoserine, metabolism, Protein Binding, Substrate Specificity
Référence
J. Biol. Chem.. 2005 Nov;280(45):38090-5