Project description:ING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites. FLAG-ING2 ChIP-chip of stably-transduced HT1080 cells in the presence of vehicle (DMSO) or etoposide. Each condition is tested in duplicate.
Project description:ING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites. Genome-wide expression profiling of HT1080 cells stably transduced with ING2 or a ING2 lipid binding mutant in the presence of vehicle (DMSO) or etoposide. Each condition is tested in triplicate
Project description:ING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites.
Project description:ING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites.
2013-12-31 | GSE47688 | GEO
Project description:Nuclear phosphatidylinositol-5-phosphate regulates ING2 stability at discrete chromatin targets in response to DNA damage
Project description:Nuclear phosphatidylinositol-5-phosphate regulates ING2 stability at discrete chromatin targets in response to DNA damage [expression]
Project description:Expression profiling of mouse ing2 -/- testis vs WT reveals gene expression differences consistent with spermatogenic arrest and infertility. Ing2 is indispensable for male germ cell development in mice. While mice deficient for Ing2 were born and grew without apparent abnormalities, male, but not female, were infertile, consistent with the highest expression of Ing2 in testes in wild-type mice and in humans. Histological and DNA content analyses in Ing2-/- testes revealed a spermatogenesis arrest at meiotic phase and enhanced apoptosis associated with increased p53, resulting in a decline in mature spermatozoa, which became more severe in older age. HDAC1 accumulation and core histone deacetylation at pachytene stage were impaired in Ing2-/- testes, suggesting that the recruitment of HDAC1 by Ing2 plays a critical role in spermatogenesis. This study establishes Ing2 as a novel mammalian regulator of spermatocyte differentiation, which coordinates spermatogenesis stage-specific histone modifications. This study has implications in understanding human male infertility.
Project description:Hydrogen sulfide (H2S), a potent signaling molecule, regulates cellular activities in plants and mammals through S-sulfhydration, a post-translational modification. The role of H2S and its molecular targets in fungi, however, remain unclear. Our study demonstrates that H2S, synthesized by cystathionine γ-lyase (CSE1) in the rice blast fungus Magnaporthe oryzae, is essential for optimal fungal infection. Excessive H2S, through S-sulfhydration, impairs fungal infectivity by negatively regulating autophagy. Using quantitative proteomics, we identified numerous S-sulfhydrated proteins in M. oryzae, including the autophagy-related protein ATG18. We found that S-sulfhydration of a critical cysteine residue (Cys78) in ATG18 is essential for its binding to phosphatidylinositol 3-phosphate (PtdIns(3)P), thereby maintaining the protein's structural stability and regulating autophagy. This study uncovers a new mechanism by which H2S-mediated S-sulfhydration controls autophagy in pathogenic fungi, and suggests the potential use of H2S donors as a strategy to control fungal diseases by targeting fungal development and infection structures, with broad implications for agriculture and disease management.
Project description:Lysosome damage activates multiple pathways to prevent lysosome-dependent cell death, including a repair mechanism involving ER-lysosome membrane contact sites, phosphatidylinositol 4-kinase-2a (PI4K2A), phosphatidylinositol-4 phosphate (PI4P) and oxysterol-binding protein-related proteins (ORPs) lipid transfer proteins. PI4K2A localizes to trans-Golgi network and endosomes yet how it is delivered to damaged lysosomes remains unknown. During acute sterile damage, and damage caused by intracellular bacteria, we show that ATG9A-containing vesicles perform a critical role in delivering PI4K2A to damaged lysosomes. ADP ribosylation factor interacting protein 2 (ARFIP2), a component of ATG9A vesicles, binds and sequesters PI4P on lysosomes, balancing ORP-dependent lipid transfer and promoting retrieval of ATG9A vesicles through recruitment of the adaptor protein complex-3 (AP-3). Our results reveal a role for mobilized ATG9A vesicles and ARFIP2 in lysosome homeostasis after damage and bacterial infection.
Project description:Lysosome damage activates multiple pathways to prevent lysosome-dependent cell death, including a repair mechanism involving ER-lysosome membrane contact sites, phosphatidylinositol 4-kinase-2a (PI4K2A), phosphatidylinositol-4 phosphate (PI4P) and oxysterol-binding protein-related proteins (ORPs) lipid transfer proteins. PI4K2A localizes to trans-Golgi network and endosomes yet how it is delivered to damaged lysosomes remains unknown. During acute sterile damage, and damage caused by intracellular bacteria, we show that ATG9A-containing vesicles perform a critical role in delivering PI4K2A to damaged lysosomes. ADP ribosylation factor interacting protein 2 (ARFIP2), a component of ATG9A vesicles, binds and sequesters PI4P on lysosomes, balancing ORP-dependent lipid transfer and promoting retrieval of ATG9A vesicles through recruitment of the adaptor protein complex-3 (AP-3). Our results reveal a role for mobilized ATG9A vesicles and ARFIP2 in lysosome homeostasis after damage and bacterial infection.