scholarly journals Ceramide Regulates Protein Synthesis by a Novel Mechanism Involving the Cellular PKR Activator RAX

2001 ◽  
Vol 276 (15) ◽  
pp. 11754-11758 ◽  
Author(s):  
Peter P. Ruvolo ◽  
Fengqin Gao ◽  
William L. Blalock ◽  
Xingming Deng ◽  
W. Stratford May
Keyword(s):  
Protein Synthesis ◽  
Kinase Inhibitor ◽  
Initiation Factor ◽  
Inhibit Protein Synthesis ◽  
Serine Threonine Kinase ◽  
Signal Molecule ◽  
Double Stranded Rna ◽  
Threonine Kinase ◽  
Universal Feature ◽  
Inhibition Of Protein Synthesis

The sphingolipid ceramide is an important second signal molecule and potent apoptotic agent. The production of ceramide is associated with virtually every known stress stimulus, and thus, generation of this sphingolipid has been suggested as a universal feature of apoptosis. Recent studies suggest that an important component of cell death following diverse stress stimuli (e.g. interleukin-3 withdrawal, sodium arsenite treatment, and peroxide treatment) is the activation of the double-stranded RNA-activable protein kinase, PKR, resulting in the inhibition of protein synthesis (Ito, T., Jagus, R., and May, W. S. (1994)Proc. Natl. Acad. Sci. U. S. A.91, 7455–7459). The recently discovered cellular PKR activator, RAX, is phosphorylated in association with PKR activation (Ito, T., Yang, M., and May, W. S. (1999)J. Biol. Chem.274, 15427–15432). Since RAX is phosphorylated by an as yet undetermined SAPK and ceramide is a potent activator of SAPKs such as JNK, a role for ceramide in the activation of RAX might be possible. Results indicate that overexpression of exogenous RAX potentiates ceramide-induced killing. Furthermore, ceramide can potently inhibit protein synthesis. Since ceramide potently promotes RAX and eukaryotic initiation factor-2α phosphorylation, a possible role for ceramide in this process may involve the activation of PKR by RAX. Since 2-aminopurine, a serine/threonine kinase inhibitor that has previously been shown to inhibit PKR, blocks both the potentiation of ceramide killing by RAX and ceramide-induced inhibition of protein synthesis, ceramide appears to promote PKR activation, at least indirectly. Collectively, these findings suggest a novel role for ceramide in the regulation of protein synthesis and apoptosis.

Phosphorylation and the control of protein synthesis

1983 ◽  
Vol 302 (1108) ◽  
pp. 127-134 ◽  
Keyword(s):  
Protein Synthesis ◽  
Protein Kinases ◽  
Molecular Mechanism ◽  
The Other ◽  
Initiation Factor ◽  
Reversible Phosphorylation ◽  
Double Stranded Rna ◽  
Inhibition Of Protein Synthesis ◽  
The One ◽  
Rabbit Reticulocytes

This paper reviews the evidence that protein synthesis in rabbit reticulocytes is regulated by the reversible phosphorylation of the initiation factor eIF-2 by protein kinases under the control of the cytoplasmic haemin concentration on the one hand, and double-stranded RNA on the other. A molecular mechanism is proposed to account for the observation that inhibition of protein synthesis occurs when considerably less than half the eIF-2 present has been phosphorylated. The question of whether phosphorylation regulates protein synthesis in other types of cell is discussed.

scholarly journals Protein synthesis persists during necrotic cell death

2005 ◽  
Vol 168 (4) ◽  
pp. 545-551 ◽  
Author(s):  
Xavier Saelens ◽  
Nele Festjens ◽  
Eef Parthoens ◽  
Isabel Vanoverberghe ◽  
Michael Kalai ◽  
...  
Keyword(s):  
Cell Death ◽  
Protein Synthesis ◽  
De Novo ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Necrotic Cell Death ◽  
Necrotic Cell ◽  
Proteolytic Activation ◽  
Double Stranded Rna ◽  
Molecular Events

Cell death is an intrinsic part of metazoan development and mammalian immune regulation. Whereas the molecular events orchestrating apoptosis have been characterized extensively, little is known about the biochemistry of necrotic cell death. Here, we show that, in contrast to apoptosis, the induction of necrosis does not lead to the shut down of protein synthesis. The rapid drop in protein synthesis observed in apoptosis correlates with caspase-dependent breakdown of eukaryotic translation initiation factor (eIF) 4G, activation of the double-stranded RNA-activated protein kinase PKR, and phosphorylation of its substrate eIF2-α. In necrosis induced by tumor necrosis factor, double-stranded RNA, or viral infection, de novo protein synthesis persists and 28S ribosomal RNA fragmentation, eIF2-α phosphorylation, and proteolytic activation of PKR are absent. Collectively, these results show that, in contrast to apoptotic cells, necrotic dying cells retain the opportunity to synthesize proteins.

scholarly journals ROLE OF SERIN/ THREONINE KINASE INHIBITOR IN THERAPY NON-ALCOHOLIC STEATOHEPATITIS AND ALCOHOLIC HEPATITIS

2019 ◽  
Vol 6 (3) ◽  
pp. 101-109
Author(s):  
Novriantika Lestari
Keyword(s):  
Signal Transduction ◽  
Liver Fibrosis ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Binding Activity ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Receptor Binding Activity ◽  
Marked Accumulation

Liver fibrosis is a reversible response to a wound healing with marked accumulation of extracellular matrix which caused by injury to the liver. Liver fibrosis can be caused by various factors including alcohol and non-alcohol steatohepatitis. The process of fibrosis serves to localize the inflammation during chronic exposure. The hepatic stem cell (HSC) has a key role in the pathogenesis of liver fibrosis. The HSC activation is characterized by increased profibrogenic mediators including members of the TGF-? superfamily. In order to enable signal transduction, the mediator needs to bind to its receptors. The serine/ threonine kinase receptor is a receptor that binds to the TGF-? superfamily ligand, including TGF-?, BMP, activin and other mediators. The ligand receptor-binding activity will stimulate signal transduction that will translocate into the nucleus and phosphorylate various transcription factors that play a role in cell proliferation, differentiation, or apoptosis. There is currently no standard therapy for liver fibrosis. Based on the central role of the serine/ threonine kinase receptor in the pathogenesis of liver fibrosis, it is thought that the use of serine/ threonine kinase inhibitors is a promising therapy.

A visible light-controllable Rho kinase inhibitor based on a photochromic phenylazothiazole

2021 ◽  
Author(s):  
Kazuya Matsuo ◽  
Sampreeth Thayyil ◽  
Mitsuyasu Kawaguchi ◽  
Hidehiko Nakagawa ◽  
Nobuyuki Tamaoki
Keyword(s):  
Protein Kinase ◽  
Visible Light ◽  
Kinase Inhibitor ◽  
Coiled Coil ◽  
Rho Kinase ◽  
Rock Inhibitor ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Rho Kinase Inhibitor

Rho-associated coiled-coil-containing protein kinase (ROCK) is a serine-threonine kinase, whose inhibitors are useful for the regulation of actomyosin system. Here, we developed a photoswitchable ROCK inhibitor based on a phenylazothiazole...

scholarly journals Simultaneous Inhibition of BCR-ABL1 Tyrosine Kinase and PAK1/2 Serine/Threonine Kinase Exerts Synergistic Effect against Chronic Myeloid Leukemia Cells

Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1544 ◽  
Author(s):  
Sylwia Flis ◽  
Ewelina Bratek ◽  
Tomasz Chojnacki ◽  
Marlena Piskorek ◽  
Tomasz Skorski
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Synergistic Effect ◽  
Tyrosine Kinase ◽  
Progenitor Cells ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Leukemia Cells ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Simultaneous Inhibition

Tyrosine kinase inhibitors (TKIs) revolutionized the treatment of chronic myeloid leukemia in the chronic phase (CML-CP). However, it is unlikely that they can completely “cure” the disease. This might be because some subpopulations of CML-CP cells such as stem and progenitor cells are resistant to chemotherapy, even to the new generation of TKIs. Therefore, it is important to look for new methods of treatment to improve therapeutic outcomes. Previously, we have shown that class I p21-activated serine/threonine kinases (PAKs) remained active in TKI-naive and TKI-treated CML-CP leukemia stem and early progenitor cells. In this study, we aimed to determine if simultaneous inhibition of BCR-ABL1 oncogenic tyrosine kinase and PAK1/2 serine/threonine kinase exert better anti-CML effect than that of individual treatments. PAK1 was inhibited by small-molecule inhibitor IPA-3 (p21-activated kinase inhibitor III), PAK2 was downregulated by specific short hairpin RNA (shRNA), and BCR-ABL1 tyrosine kinase was inhibited by imatinib (IM). The studies were conducted by using (i) primary CML-CP stem/early progenitor cells and normal hematopoietic counterparts isolated from the bone marrow of newly diagnosed patients with CML-CP and from healthy donors, respectively, (ii) CML-blast phase cell lines (K562 and KCL-22), and (iii) from BCR-ABL1-transformed 32Dcl3 cell line. Herein, we show that inhibition of the activity of PAK1 and/or PAK2 enhanced the effect of IM against CML cells without affecting the normal cells. We observed that the combined use of IM with IPA-3 increased the inhibition of growth and apoptosis of leukemia cells. To evaluate the type of interaction between the two drugs, we performed median effect analysis. According to our results, the type and strength of drug interaction depend on the concentration of the drugs tested. Generally, combination of IM with IPA-3 at the 50% of the cell kill level (EC50) generated synergistic effect. Based on our results, we hypothesize that IM, a BCR-ABL1 tyrosine kinase inhibitor, combined with a PAK1/2 inhibitor facilitates eradication of CML-CP cells.

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