TUSC3 regulates ERMA-mediated Mg²⁺ uptake for synaptic function and neurodevelopment.

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Intellectual disability (ID) presents cognitive and adaptive deficits with limited treatments.
• The gene Tumor Suppressor Candidate 3 (TUSC3) is linked to autosomal recessive ID, but its function is unknown.
• Understanding TUSC3's role is vital for developing new ID therapies.

Purpose of the Study:

• To elucidate the molecular mechanism of TUSC3 in intellectual disability.
• To investigate the therapeutic potential of targeting TUSC3-related pathways.

Main Methods:

• Utilized a TUSC3 knockout (KO) mouse model to study ID phenotypes.
• Analyzed endoplasmic reticulum (ER) Mg²⁺ homeostasis and neuronal function.
• Examined fibroblast cells from TUSC3 mutant patients.

Main Results:

• TUSC3 deficiency caused ID-like behaviors in mice, including impaired learning, memory, and social interaction.
• Loss of TUSC3 disrupts ER Mg²⁺ homeostasis, activating the PERK-eIF2α pathway and causing synaptic dysfunction.
• Patient fibroblasts showed ER Mg²⁺ deficiency and increased ER stress.
• Magnesium supplementation rescued cognitive deficits and reduced ER stress in the mouse model.

Conclusions:

• TUSC3 is essential for ER Mg²⁺ homeostasis and neuronal function.
• ER Mg²⁺ dysregulation is a key factor in neurodevelopmental disorders.
• Magnesium supplementation represents a promising therapeutic strategy for TUSC3-related ID.