scholarly journals Localization of BCR-ABL to stress granules contributes to its oncogenic function

2019 ◽  
Author(s):  
Sayaka Kashiwagi ◽  
Yoichiro Fujioka ◽  
Takeshi Kondo ◽  
Aya O. Satoh ◽  
Aiko Yoshida ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Coiled Coil ◽  
Chimeric Protein ◽  
Stress Granules ◽  
Terminal Region ◽  
Myelogenous Leukemia ◽  
Growth Defect ◽  
Causative Role ◽  
Granule Formation ◽  
N Terminus

ABSTRACTThe oncogenic tyrosine kinase BCR-ABL activates a variety of signaling pathways and plays a causative role in the pathogenesis of chronic myelogenous leukemia (CML); however, the subcellular distribution of this chimeric protein remains controversial. Here, we report that BCR-ABL is localized to stress granules and that its granular localization contributes to BCR-ABL-dependent leukemogenesis. BCR-ABL-positive granules were not colocalized with any markers for membrane-bound organelles but were colocalized with HSP90a, a component of RNA granules. The number of such granules increased with thapsigargin treatment, confirming that the granules were stress granules. Given that treatment with the ABL kinase inhibitor imatinib and elimination of the N-terminal region of BCR-ABL abolished granule formation, kinase activity and the coiled-coil domain are required for granule formation. Whereas wild-type BCR-ABL rescued the growth defect in IL-3-depleted Ba/F3 cells, mutant BCR-ABL lacking the N-terminal region failed to do so. Moreover, forced tetramerization of the N-terminus-deleted mutant could not restore the growth defect, indicating that granule formation, but not tetramerization, through its N-terminus is critical for BCR-ABL-dependent oncogenicity. Our findings together provide new insights into the pathogenesis of CML by BCR-ABL and open a window for developing novel therapeutic strategies for this disease.

scholarly journals Dual Regulatory Roles of the Extended N Terminus for Activation of the Tomato Mi-1.2 Resistance Protein

2012 ◽  
Vol 25 (8) ◽  
pp. 1045-1057 ◽  
Author(s):  
Ewa Lukasik-Shreepaathy ◽  
Erik Slootweg ◽  
Hanna Richter ◽  
Aska Goverse ◽  
Ben J. C. Cornelissen ◽  
...  
Keyword(s):  
Cell Death ◽  
Coiled Coil ◽  
Terminal Region ◽  
Regulatory Function ◽  
Cell Death Response ◽  
N Terminus ◽  
Positive Regulators ◽  
In Trans ◽  
Lrr Protein

Plant resistance (R) proteins mediate race-specific immunity and initiate host defenses that are often accompanied by a localized cell-death response. Most R proteins belong to the nucleotide binding-leucine-rich repeat (NB-LRR) protein family, as they carry a central NB-ARC domain fused to an LRR domain. The coiled-coil (CC) domain at the N terminus of some solanaceous NB-LRR proteins is extended with a solanaceae domain (SD). Tomato Mi-1.2, which confers resistance against nematodes, white flies, psyllids, and aphids, encodes a typical SD-CNL protein. Here, we analyzed the role of the extended N terminus for Mi-1.2 activation. Removal of the first part of the N terminus (Nt1) induced Mi-1.2-mediated cell death that could be suppressed by overexpression of the second half of the N-terminal region. Yet, autoactivating NB-ARC-LRR mutants require in trans coexpression of the N-terminal region to induce cell death, indicating that the N terminus functions both as a negative and as a positive regulator. Based on secondary structure predictions, we could link both activities to three distinct subdomains, a typical CC domain and two novel, structurally-conserved helical subdomains called SD1 and SD2. A negative regulatory function could be assigned to the SD1, whereas SD2 and the CC together function as positive regulators of Mi-1.2-mediated cell death.

scholarly journals Targeting USP47 overcomes tyrosine kinase inhibitor resistance and eradicates leukemia stem/progenitor cells in chronic myelogenous leukemia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hu Lei ◽  
Han-Zhang Xu ◽  
Hui-Zhuang Shan ◽  
Meng Liu ◽  
Ying Lu ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Progenitor Cells ◽  
Chronic Myelogenous Leukemia ◽  
Drug Targets ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Myelogenous Leukemia ◽  
Tki Resistance

AbstractIdentifying novel drug targets to overcome resistance to tyrosine kinase inhibitors (TKIs) and eradicating leukemia stem/progenitor cells are required for the treatment of chronic myelogenous leukemia (CML). Here, we show that ubiquitin-specific peptidase 47 (USP47) is a potential target to overcome TKI resistance. Functional analysis shows that USP47 knockdown represses proliferation of CML cells sensitive or resistant to imatinib in vitro and in vivo. The knockout of Usp47 significantly inhibits BCR-ABL and BCR-ABLT315I-induced CML in mice with the reduction of Lin−Sca1+c-Kit+ CML stem/progenitor cells. Mechanistic studies show that stabilizing Y-box binding protein 1 contributes to USP47-mediated DNA damage repair in CML cells. Inhibiting USP47 by P22077 exerts cytotoxicity to CML cells with or without TKI resistance in vitro and in vivo. Moreover, P22077 eliminates leukemia stem/progenitor cells in CML mice. Together, targeting USP47 is a promising strategy to overcome TKI resistance and eradicate leukemia stem/progenitor cells in CML.

scholarly journals Betulin, a Newly Characterized Compound in Acacia auriculiformis Bark, Is a Multi-Target Protein Kinase Inhibitor

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4599
Author(s):  
Augustine Ahmadu ◽  
Claire Delehouzé ◽  
Anas Haruna ◽  
Lukman Mustapha ◽  
Bilqis Lawal ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Inhibitor ◽  
Glycogen Synthase ◽  
Growth Factor Receptor ◽  
Binding Pocket ◽  
Stem Bark ◽  
Janus Kinase ◽  
Myelogenous Leukemia ◽  
Acacia Auriculiformis

The purpose of this work is to investigate the protein kinase inhibitory activity of constituents from Acacia auriculiformis stem bark. Column chromatography and NMR spectroscopy were used to purify and characterize betulin from an ethyl acetate soluble fraction of acacia bark. Betulin, a known inducer of apoptosis, was screened against a panel of 16 disease-related protein kinases. Betulin was shown to inhibit Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase, casein kinase 1ε (CK1ε), glycogen synthase kinase 3α/β (GSK-3 α/β), Janus kinase 3 (JAK3), NIMA Related Kinase 6 (NEK6), and vascular endothelial growth factor receptor 2 kinase (VEGFR2) with activities in the micromolar range for each. The effect of betulin on the cell viability of doxorubicin-resistant K562R chronic myelogenous leukemia cells was then verified to investigate its putative use as an anti-cancer compound. Betulin was shown to modulate the mitogen-activated protein (MAP) kinase pathway, with activity similar to that of imatinib mesylate, a known ABL1 kinase inhibitor. The interaction of betulin and ABL1 was studied by molecular docking, revealing an interaction of the inhibitor with the ABL1 ATP binding pocket. Together, these data demonstrate that betulin is a multi-target inhibitor of protein kinases, an activity that can contribute to the anticancer properties of the natural compound and to potential treatments for leukemia.

scholarly journals Puumala and Andes Orthohantaviruses Cause Transient Protein Kinase R-Dependent Formation of Stress Granules

2019 ◽  
Vol 94 (3) ◽  
Author(s):  
Wanda Christ ◽  
Janne Tynell ◽  
Jonas Klingström
Keyword(s):  
Protein Kinase ◽  
Host Cell ◽  
Stress Responses ◽  
Stress Granules ◽  
Cell Stress ◽  
Stress Granule ◽  
Hantavirus Infection ◽  
Stress Signaling ◽  
Protein Kinase R ◽  
Granule Formation

ABSTRACT Virus infection frequently triggers host cell stress signaling resulting in translational arrest; as a consequence, many viruses employ means to modulate the host stress response. Hantaviruses are negative-sense, single-stranded RNA viruses known to inhibit host innate immune responses and apoptosis, but their impact on host cell stress signaling remains largely unknown. In this study, we investigated activation of host cell stress responses during hantavirus infection. We show that hantavirus infection causes transient formation of stress granules (SGs) but does so in only a limited proportion of infected cells. Our data indicate some cell type-specific and hantavirus species-specific variability in SG prevalence and show SG formation to be dependent on the activation of protein kinase R (PKR). Hantavirus infection inhibited PKR-dependent SG formation, which could account for the transient nature and low prevalence of SG formation observed during hantavirus infection. In addition, we report only limited colocalization of hantaviral proteins or RNA with SGs and show evidence indicating hantavirus-mediated inhibition of PKR-like endoplasmic reticulum (ER) kinase (PERK). IMPORTANCE Our work presents the first report on stress granule formation during hantavirus infection. We show that hantavirus infection actively inhibits stress granule formation, thereby escaping the detrimental effects on global translation imposed by host stress signaling. Our results highlight a previously uncharacterized aspect of hantavirus-host interactions with possible implications for how hantaviruses are able to cause persistent infection in natural hosts and for pathogenesis.

The SPI2-encoded SseA chaperone has discrete domains required for SseB stabilization and export, and binds within the C-terminus of SseB and SseD

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2055-2068 ◽  
Author(s):  
Daniel V. Zurawski ◽  
Murry A. Stein
Keyword(s):  
Type Iii Secretion ◽  
Coiled Coil ◽  
Amphipathic Helix ◽  
Yeast Two Hybrid ◽  
C Terminus ◽  
N Terminus ◽  
Domain Mapping ◽  
Self Association ◽  
Discrete Domains ◽  
Two Hybrid

SseA, a key Salmonella virulence determinant, is a small, basic pI protein encoded within the Salmonella pathogenicity island 2 and serves as a type III secretion system chaperone for SseB and SseD. Both SseA partners are subunits of the surface-localized translocon module that delivers effectors into the host cell; SseB is predicted to compose the translocon sheath and SseD is a putative translocon pore subunit. In this study, SseA molecular interactions with its partners were characterized further. Yeast two-hybrid screens indicate that SseA binding requires a C-terminal domain within both partners. An additional central domain within SseD was found to influence binding. The SseA-binding region within SseB was found to encompass a predicted amphipathic helix of a type participating in coiled-coil interactions that are implicated in the assembly of translocon sheaths. Deletions that impinge upon this putative coiled-coiled domain prevent SseA binding, suggesting that SseA occupies a portion of the coiled-coil. SseA occupancy of this motif is envisioned to be sufficient to prevent premature SseB self-association inside bacteria. Domain mapping on the chaperone was also performed. A deletion of the SseA N-terminus, or site-directed mutations within this region, allowed stabilization of SseB, but its export was disrupted. Therefore, the N-terminus of SseA provides a function that is essential for SseB export, but dispensable for partner binding and stabilization.

scholarly journals The N-Terminal Region of the Human Autophagy Protein ATG16L1 Contains a Domain That Folds into a Helical Structure Consistent with Formation of a Coiled-Coil

PLoS ONE ◽  
2013 ◽  
Vol 8 (9) ◽  
pp. e76237 ◽  
Author(s):  
Rhiannon Parkhouse ◽  
Ima-Obong Ebong ◽  
Carol V. Robinson ◽  
Tom P. Monie
Keyword(s):  
Coiled Coil ◽  
Helical Structure ◽  
Terminal Region

Extracellular KIT receptor mutants, commonly found in core binding factor AML, are constitutively active and respond to imatinib mesylate

Blood ◽  
2005 ◽  
Vol 106 (12) ◽  
pp. 3958-3961 ◽  
Author(s):  
Jörg Cammenga ◽  
Stefan Horn ◽  
Ulla Bergholz ◽  
Gunhild Sommer ◽  
Peter Besmer ◽  
...  
Keyword(s):  
Imatinib Mesylate ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Therapeutic Option ◽  
Extracellular Domain ◽  
Genetic Alterations ◽  
Myelogenous Leukemia ◽  
Core Binding Factor ◽  
Kit Receptor ◽  
Binding Factor

Multiple genetic alterations are required to induce acute myelogenous leukemia (AML). Mutations in the extracellular domain of the KIT receptor are almost exclusively found in patients with AML carrying translocations or inversions affecting members of the core binding factor (CBF) gene family and correlate with a high risk of relapse. We demonstrate that these complex insertion and deletion mutations lead to constitutive activation of the KIT receptor, which induces factor-independent growth of interleukin-3 (IL-3)–dependent cells. Mutation of the evolutionary conserved amino acid D419 within the extracellular domain was sufficient to constitutively activate the KIT receptor, although high expression levels were required. Dose-dependent growth inhibition and apoptosis were observed using either the protein tyrosine kinase inhibitor imatinib mesylate (STI571, Gleevec) or by blocking the phosphoinositide-3-kinase (PI3K)–AKT pathway. Our data show that the addition of kinase inhibitors to conventional chemotherapy might be a new therapeutic option for CBF-AML expressing mutant KIT.

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