The 1970s. Since many of these histone phosphorylation residues exert their

The 1970s. Since many of these histone phosphorylation residues exert their function solely during mitosis and are dephosphorylated upon MedChemExpress A-83-01 mitotic exit, this is an example of a mitotic bookmark that has a function during mitosis and may be involved marking gene regulatory elements specifically during mitosis when factors that bind them in interphase are not bound, or in organizing the mitotic chromosome itself. One well-studied histone phosphorylation event is histone 3 serine 10 phosphorylation. H3S10ph is important for chromosome condensation, most likely through recruitment of regulatory and structural proteins, but the precise mechanisms through which this modification affects chromosome conformation are not fully understood. The kinase that is the main histone writer of this modification, Aurora B, is shown to be colocalized with other histone kinases like Haspin, which phosphorylates a second histone residues H3T3ph. Although Haspin and Aurora B can act on individual chromosome arms, centromeric histone H3 phosphorylation is regulated by a positive feedback loop of these kinases. Recruitment of Aurora B and Haspin and the subsequent hyper phosphorylation of the centromere, enables the recruitment of the chromosomal passenger complex . The CPC is required for attachment of the mitotic spindle and kinetochores to the mitotic chromatin, which is necessary for proper sister chromatid segregation and completion of cytokinesis. Phospho/Methyl Switches–H3S10ph and H3T3ph not only exert their function during PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19855441 mitosis to guide recruitment of the CPC to centromeres, but also have a function in maintaining epigenetic memory along the chromosomal arms during mitosis. Several residues that can be phosphorylated are located next to a lysine, that can be mono, di or trimethylated. For instance H3S10 is located immediately adjacent to H3K9. Many of these lysines are modified and bound by regulating factors in interphase. However when the neighboring serine or threonine becomes phosphorylated in mitosis, these regulating factors can no longer bind the modified lysine residue. The temporary phosphorylation of the neighboring residue switches the lysine off as a regulating histone modification, a so-called phospho/methyl switch. An example of such a phospho/methyl switch is H3K9me3S10pho, where the function of tri- Author Manuscript Author Manuscript Author Manuscript Author Manuscript Crit Rev Biochem Mol Biol. Author manuscript; available in PMC 2017 June 02. Oomen and Dekker Page 11 methylated H3 lysine 9 is affected by H3S10 phosphorylation in mitosis . The STA 4783 positioning of H3S10ph next to histone 3 lysine 9 di- and tri-methylation functions like a temporary shield from the chromatin binding factors. During interphase H3K9me3 acts like a heterochromatic mark, which binds to the heterochromatin protein 1. HP1 and H3K9me3 together enable heterochromatic spreading and compaction of the heterochromatin. However, when the neighboring residue H3S10 is phosphorylated during mitosis, HP1 can no longer bind to H3K9me3. This enables the heterochromatin mark to be temporary overruled by the mitotic machinery, inactivating its role in interphase chromosome architecture and allows the chromatin to be condensed in a locus-independent mitosis-specific way. Then, upon mitotic exit, the H3S10ph is dephosphorylated by the PP1gamma complex and heterochromatin protein 1 can bind H3K9me2/3 again which mediates proper reestablishment of the heterochromatin, and thus may.The 1970s. Since many of these histone phosphorylation residues exert their function solely during mitosis and are dephosphorylated upon mitotic exit, this is an example of a mitotic bookmark that has a function during mitosis and may be involved marking gene regulatory elements specifically during mitosis when factors that bind them in interphase are not bound, or in organizing the mitotic chromosome itself. One well-studied histone phosphorylation event is histone 3 serine 10 phosphorylation. H3S10ph is important for chromosome condensation, most likely through recruitment of regulatory and structural proteins, but the precise mechanisms through which this modification affects chromosome conformation are not fully understood. The kinase that is the main histone writer of this modification, Aurora B, is shown to be colocalized with other histone kinases like Haspin, which phosphorylates a second histone residues H3T3ph. Although Haspin and Aurora B can act on individual chromosome arms, centromeric histone H3 phosphorylation is regulated by a positive feedback loop of these kinases. Recruitment of Aurora B and Haspin and the subsequent hyper phosphorylation of the centromere, enables the recruitment of the chromosomal passenger complex . The CPC is required for attachment of the mitotic spindle and kinetochores to the mitotic chromatin, which is necessary for proper sister chromatid segregation and completion of cytokinesis. Phospho/Methyl Switches–H3S10ph and H3T3ph not only exert their function during PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19855441 mitosis to guide recruitment of the CPC to centromeres, but also have a function in maintaining epigenetic memory along the chromosomal arms during mitosis. Several residues that can be phosphorylated are located next to a lysine, that can be mono, di or trimethylated. For instance H3S10 is located immediately adjacent to H3K9. Many of these lysines are modified and bound by regulating factors in interphase. However when the neighboring serine or threonine becomes phosphorylated in mitosis, these regulating factors can no longer bind the modified lysine residue. The temporary phosphorylation of the neighboring residue switches the lysine off as a regulating histone modification, a so-called phospho/methyl switch. An example of such a phospho/methyl switch is H3K9me3S10pho, where the function of tri- Author Manuscript Author Manuscript Author Manuscript Author Manuscript Crit Rev Biochem Mol Biol. Author manuscript; available in PMC 2017 June 02. Oomen and Dekker Page 11 methylated H3 lysine 9 is affected by H3S10 phosphorylation in mitosis . The positioning of H3S10ph next to histone 3 lysine 9 di- and tri-methylation functions like a temporary shield from the chromatin binding factors. During interphase H3K9me3 acts like a heterochromatic mark, which binds to the heterochromatin protein 1. HP1 and H3K9me3 together enable heterochromatic spreading and compaction of the heterochromatin. However, when the neighboring residue H3S10 is phosphorylated during mitosis, HP1 can no longer bind to H3K9me3. This enables the heterochromatin mark to be temporary overruled by the mitotic machinery, inactivating its role in interphase chromosome architecture and allows the chromatin to be condensed in a locus-independent mitosis-specific way. Then, upon mitotic exit, the H3S10ph is dephosphorylated by the PP1gamma complex and heterochromatin protein 1 can bind H3K9me2/3 again which mediates proper reestablishment of the heterochromatin, and thus may.