Related Experiment Video

Updated: Sep 28, 2026

Studying RNA Interactors of Protein Kinase RNA-Activated during the Mammalian Cell Cycle
10:05

Studying RNA Interactors of Protein Kinase RNA-Activated during the Mammalian Cell Cycle

Published on: March 5, 2019

Involvement of double-stranded RNA-dependent protein kinase and phosphorylation of eukaryotic initiation

Raymond Chuen-Chung Chang1, Ka-Chun Suen, Chi-Him Ma

  • 1Department of Anatomy, Faculty of Medicine, and Central Laboratory of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Hong Kong.

Journal of Neurochemistry
|November 20, 2002
PubMed

Insights

Double-stranded RNA-dependent protein kinase (PKR) activation and eukaryotic initiation factor 2alpha (eIF2alpha) phosphorylation are key in neuroblastoma cell and neuron apoptosis. This pathway, triggered by increased calcium, offers a new neuroprotection target.

Area of Science:

  • Neuroscience
  • Molecular Biology
  • Cell Biology

Background:

  • Protein translation inhibition is crucial in apoptosis.
  • Double-stranded RNA-dependent protein kinase (PKR) is activated by double-stranded RNA and induces protein translation inhibition and apoptosis via eukaryotic initiation factor 2alpha (eIF2alpha) phosphorylation.
  • PKR is a stress kinase whose levels rise with age.

Purpose of the Study:

  • To investigate the role of PKR activation and eIF2alpha phosphorylation in neuroblastoma cell and primary neuronal apoptosis induced by beta-amyloid (Abeta) peptides, calcium ionophore A23187, and flavonoids.
  • To explore the involvement of intracellular calcium in this process.

Main Methods:

  • Over-expression of wild-type PKR and dominant-negative PKR in neuroblastoma cells.
  • Exposure of cells and primary neuronal cultures to Abeta peptide, A23187, and flavonoids.
  • Assessment of eIF2alpha phosphorylation and apoptosis.
  • Utilizing PKR knockout mice.
  • Employing the intracellular calcium chelator BAPTA-AM.

Main Results:

  • Over-expressed wild-type PKR enhanced eIF2alpha phosphorylation and apoptosis in response to Abeta peptide.
  • Dominant-negative PKR reduced Abeta peptide-induced eIF2alpha phosphorylation and apoptosis.
  • PKR knockout neurons showed reduced sensitivity to Abeta peptide toxicity.
  • Increased intracellular calcium triggered PKR and eIF2alpha pathway activation by Abeta peptide, as BAPTA-AM significantly reduced PKR phosphorylation.

Conclusions:

  • PKR activation and eIF2alpha phosphorylation are significantly involved in the apoptosis of neuroblastoma cells and primary neurons induced by various stressors, including Abeta peptide.
  • The PKR and eIF2alpha pathway activation by Abeta peptide is dependent on increased intracellular calcium.
  • This pathway represents a potential novel target for neuroprotection strategies.

More Related Videos

Molecular Modulation by Lentivirus-Delivered Specific shRNAs in Endoplasmic Reticulum Stressed Neurons10:50

Molecular Modulation by Lentivirus-Delivered Specific shRNAs in Endoplasmic Reticulum Stressed Neurons

Published on: April 24, 2021

Nuclear Magnetic Resonance Spectroscopy for the Identification of Multiple Phosphorylations of Intrinsically Disordered Proteins12:47

Nuclear Magnetic Resonance Spectroscopy for the Identification of Multiple Phosphorylations of Intrinsically Disordered Proteins

Published on: December 27, 2016

Related Concept Videos

Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Parkinson Disease ll: Pathophysiology01:24

Parkinson Disease ll: Pathophysiology

Parkinson disease (PD) is a progressive neurodegenerative disorder primarily affecting movement, with additional non-motor features. Its pathophysiology involves complex interactions among genetic susceptibility, environmental exposures, and cellular dysfunction, including dopaminergic neuron loss, protein aggregation, and mitochondrial impairment.Selective NeurodegenerationA key feature is the degeneration of dopaminergic neurons in the substantia nigra pars compacta, leading to reduced...
Phosphorylation01:02

Phosphorylation

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Alzheimer Disease ll: Pathophysiology01:23

Alzheimer Disease ll: Pathophysiology

Alzheimer disease involves structural changes in the brain that begin long before symptoms appear. The most distinctive features are extracellular neuritic plaques and intracellular neurofibrillary tangles.Neuritic plaques form in the cerebral cortex and around blood vessels. These plaques contain a dense core of beta-amyloid (Aβ)—a toxic protein fragment that clumps outside neurons. The core is surrounded by damaged neuronal extensions, as well as reactive astrocytes and microglia. Abnormal...
The Unfolded Protein Response01:37

The Unfolded Protein Response

The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...
Calmodulin-dependent Signaling01:16

Calmodulin-dependent Signaling

Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...