Neuron-specific translational control shift ensures proteostatic resilience during ER stress

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Biology

Background:

• Proteostasis is crucial for neuronal survival, especially in specialized post-mitotic cells.
• Endoplasmic reticulum (ER) stress triggers a survival response via PERK-mediated eIF2α phosphorylation, reducing protein synthesis.
• Neurons exhibit unusual tolerance to PERK dysfunction, hinting at cell-specific proteostatic mechanisms.

Purpose of the Study:

• To investigate the mechanisms underlying neuronal resilience to proteostatic stress despite PERK dysfunction.
• To identify cell type-specific pathways ensuring translational control during ER stress in neurons.

Main Methods:

• Analysis of PERK-deficient neurons under ER stress conditions.
• Assessment of translational control and ATF4 response.
• Identification of molecular pathways involved in translational regulation.

Main Results:

• PERK-deficient neurons maintain translational control during ER stress, unlike other cell types.
• The ATF4 response is rescaled, but protein synthesis reduction is preserved.
• The Haem-regulated inhibitor (HRI) and angiogenin (ANG) pathways were identified as key drivers of translational control.

Conclusions:

• Neurons have an intricate backup mechanism for translational control during ER stress.
• This HRI- and ANG-mediated pathway explains neuronal resilience to proteostatic stress.
• The findings resolve the long-standing observation of neuronal tolerance to proteostatic stress.