scholarly journals Chromatin insulator bodies are nuclear structures that form in response to osmotic stress and cell death

2013 ◽  
Vol 202 (2) ◽  
pp. 261-276 ◽  
Author(s):  
Todd Schoborg ◽  
Ryan Rickels ◽  
Josh Barrios ◽  
Mariano Labrador
Keyword(s):  
Cell Death ◽  
Bound State ◽  
Mitogen Activated Protein Kinase ◽  
Independent Manner ◽  
Multiple Protein ◽  
Spatial Reorganization ◽  
Insulator Proteins ◽  
Mitogen Activated Protein ◽  
Nuclear Structures ◽  
Stress Foci

Chromatin insulators assist in the formation of higher-order chromatin structures by mediating long-range contacts between distant genomic sites. It has been suggested that insulators accomplish this task by forming dense nuclear foci termed insulator bodies that result from the coalescence of multiple protein-bound insulators. However, these structures remain poorly understood, particularly the mechanisms triggering body formation and their role in nuclear function. In this paper, we show that insulator proteins undergo a dramatic and dynamic spatial reorganization into insulator bodies during osmostress and cell death in a high osmolarity glycerol–p38 mitogen-activated protein kinase–independent manner, leading to a large reduction in DNA-bound insulator proteins that rapidly repopulate chromatin as the bodies disassemble upon return to isotonicity. These bodies occupy distinct nuclear territories and contain a defined structural arrangement of insulator proteins. Our findings suggest insulator bodies are novel nuclear stress foci that can be used as a proxy to monitor the chromatin-bound state of insulator proteins and provide new insights into the effects of osmostress on nuclear and genome organization.

scholarly journals Stat5 activation enables erythropoiesis in the absence of EpoR and Jak2

Blood ◽  
2008 ◽  
Vol 111 (9) ◽  
pp. 4511-4522 ◽  
Author(s):  
Florian Grebien ◽  
Marc A. Kerenyi ◽  
Boris Kovacic ◽  
Thomas Kolbe ◽  
Verena Becker ◽  
...  
Keyword(s):  
Fetal Liver ◽  
Janus Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Independent Manner ◽  
Hematopoietic Stem ◽  
Tyrosine Kinase Signaling ◽  
Fusion Construct ◽  
Downstream Effector ◽  
Kit Receptor ◽  
Mitogen Activated Protein

Abstract Erythropoiesis requires erythropoietin (Epo) and stem cell factor (SCF) signaling via their receptors EpoR and c-Kit. EpoR, like many other receptors involved in hematopoiesis, acts via the kinase Jak2. Deletion of EpoR or Janus kinase 2 (Jak2) causes embryonic lethality as a result of defective erythropoiesis. The contribution of distinct EpoR/Jak2-induced signaling pathways (mitogen-activated protein kinase, phosphatidylinositol 3-kinase, signal transducer and activator of transcription 5 [Stat5]) to functional erythropoiesis is incompletely understood. Here we demonstrate that expression of a constitutively activated Stat5a mutant (cS5) was sufficient to relieve the proliferation defect of Jak2−/− and EpoR−/− cells in an Epo-independent manner. In addition, tamoxifen-induced DNA binding of a Stat5a–estrogen receptor (ER)* fusion construct enabled erythropoiesis in the absence of Epo. Furthermore, c-Kit was able to enhance signaling through the Jak2-Stat5 axis, particularly in lymphoid and myeloid progenitors. Although abundance of hematopoietic stem cells was 2.5-fold reduced in Jak2−/− fetal livers, transplantation of Jak2−/−-cS5 fetal liver cells into irradiated mice gave rise to mature erythroid and myeloid cells of donor origin up to 6 months after transplantation. Cytokine- and c-Kit pathways do not function independently of each other in hematopoiesis but cooperate to attain full Jak2/Stat5 activation. In conclusion, activated Stat5 is a critical downstream effector of Jak2 in erythropoiesis/myelopoiesis, and Jak2 functionally links cytokine- with c-Kit-receptor tyrosine kinase signaling.

scholarly journals MAP Kinase OsMEK2 and OsMPK1 Signaling for Ferroptotic Cell Death in Rice-Magnaporthe oryzae Interactions

2020 ◽  
Author(s):  
Sarmina Dangol ◽  
Raksha Singh ◽  
Khoa Nam Nguyen ◽  
Yafei Chen ◽  
Juan Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Map Kinase ◽  
Signaling Pathways ◽  
Magnaporthe Oryzae ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Microbial Pathogens ◽  
Blast Disease ◽  
Related Cell ◽  
Mitogen Activated Protein

ABSTRACTMitogen-activated protein kinase (MAPK) signaling is required for plant cell death responses to invading microbial pathogens. Ferric ions and reactive oxygen species (ROS) accumulate in rice (Oryza sativa) tissues undergoing cell death during Magnaporthe oryzae infection. Here, we report that rice MAP kinase (OsMEK2 and OsMPK1) signaling cascades are involved in iron- and ROS-dependent ferroptotic cell death responses of rice to M. oryzae infection. OsMEK2 interacted with OsMPK1 in the cytoplasm, and OsMPK1 moved from the cytoplasm into the nucleus to bind to the OsWRKY90 transcription factor. OsMEK2 expression may trigger OsMPK1-OsWRKY90 signaling pathways in the nucleus. Avirulent M. oryzae infection in ΔOsmek2 mutant rice did not trigger iron and ROS accumulation and lipid peroxidation, and also downregulated OsMPK1, OsWRKY90, OsRbohB, and OsPR-1b expression. However, OsMEK2 overexpression induced ROS-and iron-dependent cell death in rice during M. oryzae infection. The downstream MAP kinase (OsMPK1) overexpression induced ROS- and iron-dependent ferroptotic cell death in the compatible rice-M. oryzae interaction. These data suggest that the OsMEK2-OsMPK1-OsWRKY90 signaling cascade is involved in the ferroptotic cell death in rice. The small-molecule inducer erastin triggered iron- and lipid ROS-dependent, but OsMEK2-independent, ferroptotic cell death in ΔOsmek2 mutant plants during M. oryzae infection. Disease-related cell death was lipid ROS-dependent and iron-independent in the ΔOsmek2 mutant plants. These combined results suggest that OsMEK2 and OsMPK1 expression positively regulates iron- and ROS-dependent ferroptotic cell death via OsMEK2-OsMPK1-OsWRKY90 signaling pathways, and blast disease (susceptibility)-related cell death was ROS-dependent but iron-independent in rice-M. oryzae interactions.

scholarly journals Pro-apoptotic and pro-proliferation functions of the JNK pathway of Drosophila : roles in cell competition, tumorigenesis and regeneration

Open Biology ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 180256 ◽  
Author(s):  
Noelia Pinal ◽  
Manuel Calleja ◽  
Ginés Morata
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Animal Species ◽  
Mitogen Activated Protein Kinase ◽  
Intrinsic Properties ◽  
Cell Competition ◽  
Apparent Paradox ◽  
Jnk Pathway ◽  
Mitogen Activated Protein ◽  
Cellular Context

The Jun N-terminal kinase (JNK) is a member of the mitogen-activated protein kinase family. It appears to be conserved in all animal species where it regulates important physiological functions involved in apoptosis, cell migration, cell proliferation and regeneration. In this review, we focus on the functions of JNK in Drosophila imaginal discs, where it has been reported that it can induce both cell death and cell proliferation. We discuss this apparent paradox in the light of recent findings and propose that the pro-apoptotic and the pro-proliferative functions are intrinsic properties of JNK activity. Whether one function or another is predominant depends on the cellular context.

scholarly journals 1-O-Hexyl-2,3,5-Trimethylhydroquinone Ameliorates l-DOPA-Induced Cytotoxicity in PC12 Cells

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 867 ◽  
Author(s):  
Hyun Park ◽  
Jong Kang ◽  
Myung Lee
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Pc12 Cells ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Mitogen Activated Protein Kinase ◽  
Protective Effects ◽  
Extracellular Signal ◽  
Dopaminergic Neuronal Cell ◽  
Mitogen Activated Protein

1-O-Hexyl-2,3,5-trimethylhydroquinone (HTHQ) has previously been found to have effective anti-oxidant and anti-lipid-peroxidative activity. We aimed to elucidate whether HTHQ can prevent dopaminergic neuronal cell death by investigating the effect on l-DOPA-induced cytotoxicity in PC12 cells. HTHQ protected from both l-DOPA-induced cell death and superoxide dismutase activity reduction. When assessing the effect of HTHQ on oxidative stress-related signaling pathways, HTHQ inhibited l-DOPA-induced phosphorylation of sustained extracellular signal-regulated kinases (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK1/2). HTHQ also normalized l-DOPA-reduced Bcl-2-associated death protein (Bad) phosphorylation and Bcl-2-associated X protein (Bax) expression, promoting cell survival. Taken together, HTHQ exhibits protective effects against l-DOPA-induced cell death through modulation of the ERK1/2-p38MAPK-JNK1/2-Bad-Bax signaling pathway in PC12 cells. These results suggest that HTHQ may show ameliorative effects against oxidative stress-induced dopaminergic neuronal cell death, although further studies in animal models of Parkinson’s disease are required to confirm this.

scholarly journals Targeted Inhibition of p38 Mitogen-activated Protein Kinase Antagonizes Cardiac Injury and Cell Death Following Ischemia-Reperfusionin Vivo

2004 ◽  
Vol 279 (15) ◽  
pp. 15524-15530 ◽  
Author(s):  
Robert A. Kaiser ◽  
Orlando F. Bueno ◽  
Daniel J. Lips ◽  
Pieter A. Doevendans ◽  
Fred Jones ◽  
...  
Keyword(s):  
Cell Death ◽  
Protein Kinase ◽  
Cardiac Injury ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Targeted Inhibition

scholarly journals Violacein induces p44/42 mitogen-activated protein kinase-mediated solid tumor cell death and inhibits tumor cell migration

2015 ◽  
Vol 12 (1) ◽  
pp. 1443-1448 ◽  
Author(s):  
TORAL MEHTA ◽  
KOEN VERCRUYSSE ◽  
TERRANCE JOHNSON ◽  
ANTHONY OKECHUKWU EJIOFOR ◽  
ELBERT MYLES ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Migration ◽  
Protein Kinase ◽  
Tumor Cell ◽  
Solid Tumor ◽  
Mitogen Activated Protein Kinase ◽  
Tumor Cell Death ◽  
Tumor Cell Migration ◽  
Mitogen Activated Protein
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