RNA protein granules modulate tau isoform expression and induce neuronal sprouting

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Neuronal Tau protein exists in various isoforms, with altered expression during development and disease.
• The roles of specific mRNA-binding proteins in regulating Tau expression are not fully understood.

Purpose of the Study:

• To investigate the function of G3BP1 and IMP1 in modulating neuronal Tau expression.
• To explore the potential role of ribonucleoprotein (RNP) granules in this process.

Main Methods:

• Expression of G3BP1 and IMP1 in neuronal cells.
• Analysis of Tau mRNA and protein isoform composition.
• Assessment of neurite formation and process growth.
• Utilizing G3BP1 deletion constructs to assess structure-function relationships.

Main Results:

• G3BP1 and IMP1 induce the formation of neuronal RNP granules.
• RNP granule formation significantly increases the ratio of high molecular weight to low molecular weight Tau mRNA (>30-fold) and Tau protein (~12-fold).
• RNP granule formation is correlated with increased neurite formation and enhanced process growth.

Conclusions:

• Multivalent proteins G3BP1 and IMP1 regulate Tau isoform expression via RNP granule formation.
• RNP granules possess a morphoregulatory function in neuronal development and disease contexts.
• The ability to induce granule formation is critical for G3BP1's effects on Tau expression and neuronal sprouting.