Aurora1 phosphorylation activity on histone H3 and its cross‐talk with other post‐translational histone modifications in Arabidopsis

Abstract

SUMMARYThe enzymological properties of AtAurora1, a kinase responsible for the cell cycle-dependent phosphorylation of histone H3 at S10, and its cross-talk with other post-translational histone modifications, were determined. In vitro phosphorylation of H3S10 by AtAurora1 is strongly increased by K9 acetylation, and decreased by K14 acetylation and T11 phosphorylation. However, S10 phosphorylation activity is unaltered by mono-, di-or trimethylation of K9. An interference of H3K9 dimethylation by SUVR4 occurs by a pre-existing phosphorylation at S10. Hence, cross-talk in plants exists between phosphorylation of H3S10 and methylation, acetylation or phosphorylation of neighbouring amino acid residues. AtAurora1 undergoes autophosphorylation in vivo regardless of the presence of substrate, and forms dimers in planta. Of the three ATP-competitive Aurora inhibitors tested, Hesperadin was most effective in reducing the in vivo kinase activity of AtAurora1. Hesperadin consistently inhibited histone H3S10 phosphorylation during mitosis in Arabidopsis cells, but did not affect other H3 post-translational modifications, suggesting a specific inhibition of AtAurora in vivo. Inactivation of AtAurora also caused lagging chromosomes in a number of anaphase cells, but, unlike the situation in mammalian cells, Hesperadin did not influence the microtubule dynamics in dividing cells.

Preferential Phosphorylation on Old Histones during Early Mitosis in Human Cells

“…4, E and F). Our results were consistent with previous in vitro biochemical studies, which showed that Aurora B does not have substrate preference for a trimethylated form of H3K9 peptide, among other modified forms of the same peptide (35)(36)(37).…”

“…Peptide sequences that were not analyzed in this study are in gray. The H3.1/2(27-40) peptide is in blue, and the H3.3 (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) peptide is in red. The line connecting the four acetylation marks on H4(2-16) peptide indicates only the four-ac was enriched on old H4 but not two-ac or three-ac (Table 1).…”

“…For phosphorylated peptides that were not included in the synthetic peptide library, an average correction factor generated from all the peptides with the same histone backbone was used. For the histone H3.3 (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) peptide, the H1.4 (25)(26)(27)(28)(29)(30)(31)(32) peptide, and the K9M(9 -17) peptide, no correction factors were available, and thus no correction was performed.…”

High-Resolution Temporal Profiling of Transcripts during Arabidopsis Leaf Senescence Reveals a Distinct Chronology of Processes and Regulation

“…Downregulation of this group of genes after completion of the cell division and expansion stages of leaf development is to be expected, but the increase in expression at the end of senescence is unanticipated. AURORA1 has been shown to phosphorylate histone H3 at Ser10 (Demidov et al, 2009), and, in mammalian cells, this modification has been suggested to have a crucial role in transcription and apoptosis as well as in cell division (Prigent and Dimitrov, 2003). These proteins may alter chromatin structure in late senescence to allow DNA fragmentation and eventual degradation.…”

“…This group is highly enriched for genes involved in the cytoskeleton (see Supplemental Figure 3B online), with members of the a-tubulin family (TUA2, 4, and 5), actin genes, ACT3 and ACT11, and two aurora genes (AURORA1 and AURORA2) encoding kinase proteins that have a role in histone phosphorylation and have been reported to be associated with microtubule spindles and abundantly transcribed only in dividing cells (Demidov et al, 2005(Demidov et al, , 2009). Downregulation of this group of genes after completion of the cell division and expansion stages of leaf development is to be expected, but the increase in expression at the end of senescence is unanticipated.…”