PKR-driven ISR signaling controls synaptic translation and structural plasticity in an age-dependent manner

Area of Science:

• Neuroscience
• Molecular Biology
• Cellular Biology

Background:

• The integrated stress response (ISR) is crucial for protein homeostasis and cell fate.
• ISR activation influences synaptic plasticity and cognitive function.
• The precise localization and function of ISR components within neuronal synapses remain largely unknown.

Purpose of the Study:

• To investigate the presence, activity, and localization of the PKR-eIF2α axis within neuronal synapses.
• To determine the role of the PKR-eIF2α axis in maintaining synaptic proteostasis and structural plasticity.
• To assess the age-dependent regulation of synaptic function by the PKR-eIF2α axis.

Main Methods:

• Immunofluorescence and biochemical assays to detect PKR and eIF2α localization at synapses.
• Analysis of synaptic protein abundance and synthesis in wild-type and PKR-deficient models.
• Assessment of synaptic size and structural plasticity in relation to PKR activity and age.

Main Results:

• PKR and eIF2α are confirmed to be localized at neuronal synapses.
• A dynamic PKR-eIF2α axis regulates synaptic size and protein abundance in an age-dependent manner.
• PKR deficiency results in elevated protein synthesis in synapse-enriched fractions, indicating a role in synaptic proteostasis.

Conclusions:

• The PKR-eIF2α axis is a novel regulator of synaptic structural plasticity.
• Targeting the ISR, particularly the PKR pathway, may offer therapeutic strategies for neurological disorders associated with cognitive decline.
• The ISR plays a critical role in maintaining neuronal health and function at the synaptic level.