Inositol phosphate kinase Vip1p interacts with histone chaperone Asf1p in Saccharomyces cerevisiae

Abstract

Histone eviction and deposition are critical steps in many nuclear processes. The histone H3/H4 chaperone Asf1p is highly conserved and is involved in DNA replication, DNA repair, and transcription. To identify the factors concerned with anti-silencing function 1 (ASF1), we purified Asf1p-associated factors from the yeast Saccharomyces cerevisiae by a GST pull-down experiment, and mass spectrometry analysis was performed. Several factors are specifically associated with Asf1p, including Vip1p. VIP1 is conserved from yeast to humans and encodes inositol hexakisphoshate and inositol heptakisphosphate kinase. Vip1p interacted with Asf1p as a dimer or in a complex with another protein(s). Deletion of VIP1 did not affect the interaction between Asf1p and other Asf1p-associated factors. An in vitro GST pull-down assay indicated a direct interaction between Asf1p and Vip1p, and the interaction between the two factors in vivo was detected by an immunoprecipitation experiment. Furthermore, genetic experiments revealed that VIP1 disruption increased sensitivity to 6-azauracil (6-AU), but not to DNA-damaging reagents in wild-type and ASF1-deleted strains. It is thought that 6-AU decreases nucleotide levels and reduces transcription elongation. These observations suggest that the association of Asf1p and Vip1p may be implicated in transcription elongation.

VIH2 Regulates the Synthesis of Inositol Pyrophosphate InsP8 and Jasmonate-Dependent Defenses in Arabidopsis

“…A previously identified vip1D-associated growth defect on 6-azauracil in yeast (Osada et al, 2012) was rescued by Arabidopsis VIH1 and VIH2, suggesting that these proteins execute Vip1-like activities in vivo ( Figure 2C). In contrast, ectopic overexpression of Kcs1 under similar conditions failed to cause growth complementation of the single vip1D strain ( Figure 2C).…”

Arabidopsis PFA-DSP-Type Phosphohydrolases Target Specific Inositol Pyrophosphate Messengers

“…To investigate the physiological consequences of Arabidopsis PFA-DSP activities in vivo , we carried out heterologous expression experiments in baker’s yeast. To this end, we investigated the sensitivity of our siw 14Δ yeast strain under conditions where phenotypes for siw 14Δ strains and other yeast mutants defective in PP-InsP homeostasis have been reported previously ,,− and selected the fungal toxin wortmannin that caused a severe siw 14Δ-associated growth defect. Previous observations that kcs 1Δ yeast cells are resistant to wortmannin suggest that wortmannin sensitivity of siw 14Δ yeast might be related to Kcs1-dependent PP-InsPs.…”

Wheat inositol pyrophosphate kinase TaVIH2-3B modulates cell-wall composition for drought tolerance in Arabidopsis

“…Yeast VIP1 was shown to interact with histone H3/H4 chaperone, ASF1. VIP1 and ASF1 counterparts in S. pombe functionally regulate actin-related protein-2/3 complexes and thereby participate in the fate of cell morphology 19 . Protein-protein interaction studies using human PPIP5K1 identified multiple proteins involved in vesicle-mediated trafficking, lipid metabolism and cytoskeletal organization 45 .…”

“…Furthermore, in yeast, role of inositol pyrophosphate kinase was also implicated in vacuolar morphology and cell wall integrity 3 . Histone H3/H4 chaperone, Asf1p is known to interact with the VIP1 (VIH) protein, thereby, suggesting this interaction important for transcription elongation 19 . Therefore, the function of the protein could also be studied in context to their interacting partners.…”