scholarly journals RNase L Induces Expression of A Novel Serine/Threonine Protein Kinase, DRAK1, to Promote Apoptosis

2019 ◽  
Vol 20 (14) ◽  
pp. 3535 ◽  
Author(s):  
Praveen Manivannan ◽  
Vidita Reddy ◽  
Sushovita Mukherjee ◽  
Kirsten Neytania Clark ◽  
Krishnamurthy Malathi
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Cellular Localization ◽  
Caspase 3 ◽  
Parp Inhibitors ◽  
Rnase L ◽  
Oligoadenylate Synthetase ◽  
Cytochrome C Release ◽  
Interferon Induction ◽  
Death Associated Protein Kinase

Apoptosis of virus-infected cells is an effective antiviral mechanism in addition to interferon induction to establish antiviral state to restrict virus spread. The interferon-inducible 2′–5′ oligoadenylate synthetase/RNase L pathway results in activation of RNase L in response to double stranded RNA and cleaves diverse RNA substrates to amplify interferon induction and promote apoptosis. Here we show that RNase L induces expression of Death-associated protein kinase-Related Apoptosis-inducing protein Kinase 1 (DRAK1), a member of the death-associated protein kinase family and interferon-signaling pathway is required for induction. Overexpression of DRAK1 triggers apoptosis in the absence of RNase L activation by activating c-Jun N-terminal kinase (JNK), translocation of BCL2 Associated X (Bax) to the mitochondria accompanied by cytochrome C release and loss of mitochondrial membrane potential promoting cleavage of caspase 3 and Poly(ADP-Ribose) Polymerase 1 (PARP). Inhibitors of JNK and caspase 3 promote survival of DRAK1 overexpressing cells demonstrating an important role of JNK signaling pathway in DRAK1-mediated apoptosis. DRAK1 mutant proteins that lack kinase activity or nuclear localization fail to induce apoptosis highlighting the importance of cellular localization and kinase function in promoting cell death. Our studies identify DRAK1 as a mediator of RNase L-induced apoptosis.

scholarly journals A phenolic small molecule inhibitor of RNase L prevents cell death from ADAR1 deficiency

2020 ◽  
Vol 117 (40) ◽  
pp. 24802-24812 ◽  
Author(s):  
Salima Daou ◽  
Manisha Talukdar ◽  
Jinle Tang ◽  
Beihua Dong ◽  
Shuvojit Banerjee ◽  
...  
Keyword(s):  
Cell Death ◽  
Protein Kinase ◽  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Therapeutic Potential ◽  
Protein Kinase Inhibitors ◽  
Response To Treatment ◽  
Rnase L ◽  
Oligoadenylate Synthetase ◽  
In Cells

The oligoadenylate synthetase (OAS)–RNase L system is an IFN-inducible antiviral pathway activated by viral infection. Viral double-stranded (ds) RNA activates OAS isoforms that synthesize the second messenger 2-5A, which binds and activates the pseudokinase-endoribonuclease RNase L. In cells, OAS activation is tamped down by ADAR1, an adenosine deaminase that destabilizes dsRNA. Mutation of ADAR1 is one cause of Aicardi-Goutières syndrome (AGS), an interferonopathy in children. ADAR1 deficiency in human cells can lead to RNase L activation and subsequent cell death. To evaluate RNase L as a possible therapeutic target for AGS, we sought to identify small-molecule inhibitors of RNase L. A 500-compound library of protein kinase inhibitors was screened for modulators of RNase L activity in vitro. We identified ellagic acid (EA) as a hit with 10-fold higher selectivity against RNase L compared with its nearest paralog, IRE1. SAR analysis identified valoneic acid dilactone (VAL) as a superior inhibitor of RNase L, with 100-fold selectivity over IRE1. Mechanism-of-action analysis indicated that EA and VAL do not bind to the pseudokinase domain of RNase L despite acting as ATP competitive inhibitors of the protein kinase CK2. VAL is nontoxic and functional in cells, although with a 1,000-fold decrease in potency, as measured by RNA cleavage activity in response to treatment with dsRNA activator or by rescue of cell lethality resulting from self dsRNA induced by ADAR1 deficiency. These studies lay the foundation for understanding novel modes of regulating RNase L function using small-molecule inhibitors and avenues of therapeutic potential.

scholarly journals The Cellular Localization of the p42 and p46 Oligoadenylate Synthetase 1 Isoforms and Their Impact on Mitochondrial Respiration

Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1122 ◽  
Author(s):  
Stig Skrivergaard ◽  
Monica Skou Jensen ◽  
Tine Breckling Rolander ◽  
Tram Bao Ngoc Nguyen ◽  
Amanda Bundgaard ◽  
...  
Keyword(s):  
High Resolution ◽  
Fluorescence Microscopy ◽  
Cellular Localization ◽  
Immunoblot Analysis ◽  
Rnase L ◽  
Oligoadenylate Synthetase ◽  
Innate Response ◽  
Viral Pathogens ◽  
The Difference ◽  
Caax Motif

The importance of the IFN-induced oligoadenylate synthetase (OAS) proteins and the OAS/RNase L pathway in the innate response against viral pathogens is well-established, however the observed differences in anti-viral activity between the human OAS1 p46 and p42 isoforms are not fully understood. The protein expression of these isoforms is determined by the SNP rs10774671, either being an A or a G allele resulting in expression of either the p42 or the p46 isoform. Using fluorescence microscopy and immunoblot analysis of fractionated cell samples, we show here that the CaaX motif is of key importance to the cellular localization. The OAS1 p42 isoform is mainly located in the cytosol, whereas the p46 isoform with a C-terminal CaaX motif is translocated to membranous organelles, like the mitochondria. We furthermore observed differences between p42 and p46 in their effect on mitochondrial physiology using high resolution respirometry and fluorometry. Overexpression of OAS1 p42 and IFN-β treatment of HeLa cells (AA genotype) resulted in significantly increased respiration, which was not seen with p46 overexpression. The difference in subcellular localization and mitochondrial effect of these two OAS1 isoforms might help to explain the anti-viral mechanisms that differentiate these proteins.

scholarly journals Positive feedback of protein kinase C proteolytic activation during apoptosis

2002 ◽  
Vol 368 (3) ◽  
pp. 905-913 ◽  
Author(s):  
Sabrina LEVERRIER ◽  
Alice VALLENTIN ◽  
Dominique JOUBERT
Keyword(s):  
Pituitary Adenoma ◽  
Protein Kinase ◽  
Caspase 3 ◽  
Initial Step ◽  
Genotoxic Stress ◽  
Cytochrome C Release ◽  
Proteolytic Activation ◽  
Kinase C ◽  
Pkc Isoforms ◽  
Protein Kinase Cα

In contrast with protein kinase Cα (PKCα) and PKC∊, which are better known for promoting cell survival, PKCΔ is known for its pro-apoptotic function, which is exerted mainly through a caspase-3-dependent proteolytic activation pathway. In the present study, we used the rat GH3B6 pituitary adenoma cell line to show that PKCα and PKC∊ are activated and relocalized together with PKCΔ when apoptosis is induced by a genotoxic stress. Proteolytic activation is a crucial step used by the three isoforms since: (1) the catalytic domains of the PKCα, PKC∊ or PKCΔ isoforms (CDα, CD∊ and CDΔ respectively) accumulated, and this accumulation was dependent on the activity of both calpain and caspase; and (2) transient expression of CDα, CD∊ or CDΔ sufficed to induce apoptosis. However, following this initial step of proteolytic activation, the pathways diverge; cytochrome c release and caspase-3 activation are induced by CD∊ and CDΔ, but not by CDα. Another interesting finding of the present study is the proteolysis of PKCΔ induced by CD∊ expression that revealed the existence of a cross-talk between PKC isoforms during apoptosis. Hence the PKC family may participate in the apoptotic process of pituitary adenoma cells at two levels: downstream of caspase and calpain, and via retro-activation of caspase-3, resulting in the amplification of its own proteolytic activation.

scholarly journals Protein Kinase C Delta Cleavage Initiates an Aberrant Signal Transduction Pathway after Cardiac Arrest and Oxygen Glucose Deprivation

2005 ◽  
Vol 25 (6) ◽  
pp. 730-741 ◽  
Author(s):  
Ami P. Raval ◽  
Kunjan R. Dave ◽  
Ricardo Prado ◽  
Laurence M. Katz ◽  
Raul Busto ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Cytochrome C ◽  
Caspase 3 ◽  
Glucose Deprivation ◽  
Oxygen Glucose Deprivation ◽  
Cytochrome C Release ◽  
Early Reperfusion ◽  
Kinase C

Protein kinase C (PKC) isozymes have been known to mediate a variety of complex and diverse cellular functions. δPKC has been implicated in mediating apoptosis. Using two models of cerebral ischemia, cardiac arrest in rats and oxygen glucose deprivation (OGD) in organotypic hippocampal slices, we tested whether an ischemic insult promoted δPKC cleavage during the reperfusion and whether the upstream pathway involved release of cytochrome c and caspase 3 cleavage. We showed that cardiac arrest/OGD significantly enhanced δPKC translocation and increased its cleavage at 3 h of reperfusion. Since δPKC is one of the substrates for caspase 3, we next determined caspase 3 activation after cardiac arrest and OGD. The maximum decrease in levels of procaspase 3 was observed at 3 h of reperfusion after cardiac arrest and OGD. We also determined cytochrome c release, since it is upstream of caspase 3 activation. Cytochrome c in cytosol increased at 1 h of reperfusion after cardiac arrest/OGD. Inhibition of either δPKC/caspase 3 during OGD and early reperfusion resulted in neuroprotection in CA1 region of hippocampus. Our results support the deleterious role of δPKC in reperfusion injury. We propose that early cytochrome c release and caspase 3 activation promote δPKC translocation/cleavage.

Downregulation of Death-associated Protein Kinase 3 and Caspase-3 Correlate to the Progression and Poor Prognosis of Gliomas

2016 ◽  
Vol 2 (3) ◽  
pp. 72 ◽  
Author(s):  
Songtao Qi ◽  
Ye Song ◽  
Tianshi Que ◽  
Hao Long ◽  
Xi′an Zhang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Poor Prognosis ◽  
Caspase 3 ◽  
Death Associated Protein Kinase
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