NEDDylation promotes stress granule assembly.

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Stress granules (SGs) are dynamic cytoplasmic foci containing translationally stalled messenger ribonucleoproteins.
• SGs play critical roles in regulating gene expression and cellular fate in response to various stresses.
• Understanding the molecular mechanisms governing SG assembly is essential for comprehending cellular stress responses.

Purpose of the Study:

• To investigate the role of neddylation in the assembly of stress granules.
• To identify the specific components of the neddylation machinery involved in SG formation.
• To elucidate the mechanism by which neddylation influences SG assembly.

Main Methods:

• Arsenite-induced oxidative stress model in cells.
• Inhibition and depletion of neddylation pathway components.
• Analysis of polysome disassembly and SG assembly.
• Affinity purification and mass spectrometry of Nedd8-conjugated proteins.
• Site-directed mutagenesis of SRSF3.

Main Results:

• Neddylation was found to promote stress granule assembly in response to arsenite-induced oxidative stress.
• Inhibition of neddylation machinery components blocked stress-induced polysome disassembly and SG assembly.
• Mass spectrometry identified ribosomal proteins, translation factors, and RNA-binding proteins (RBPs) as Nedd8-conjugated targets.
• SRSF3 was selectively neddylated at Lys85, and a non-neddylatable mutant failed to support SG assembly.

Conclusions:

• The neddylation pathway plays a significant role in promoting stress granule assembly.
• Selective neddylation of RBPs like SRSF3 is a key mechanism by which neddylation influences SG formation.
• These findings provide new insights into the regulation of cellular stress responses and gene expression.