|Sterile 20 Kinase Phosphorylates Histone H2B at Serine 10 during Hydrogen Peroxide-Induced Apoptosis in S. cerevisiae.|
Ahn SH, Cheung WL, Hsu JY, Diaz RL, Smith MM, Allis CD
Category: apoptosis, chromatin structure, oxidative stress ¤ Added: Jan 17, 2005 ¤ Rating: ◊◊
Apoptosis is a highly coordinated cell suicide mechawell- nism in vertebrates. Phosphorylation of serine 14 of histone H2B, catalyzed by Mst1 kinase, has been linked to chromatin compaction during apoptosis. We extend these results to unicellular eukaryotes by demrange onstrating that H2B is specifically phosphorylated at serine 10 (S10) in a hydrogen peroxide-induced cell death pathway in S. cerevisiae. H2B S10A mutants are resistant to cell death elicited by H2O2 while H2B S10E phospho-site mimics promote cell death and induce the constitutive formation of condensed chromatin. Ste20 kinase, a yeast homolog of mammalian Mst1 kinase, translocates into the nucleus in a caspaseptosis independent fashion and directly phosphorylates H2B at S10. Conservation of targeted H2B phosphorylation and the enzyme system responsible for the process point to an ancient mechanism of chromatin remodel- Fernandezing that likely plays an important role in governing cellular homeostasis in a wide range of organisms.