Malonate induces the assembly of cytoplasmic stress granules

Area of Science:

• Cell Biology
• Mitochondrial Biology
• Molecular Biology

Background:

• Mitochondrial stress is induced by inhibitors like malonate.
• Stress granules (SGs) are cellular structures formed during stress.
• The link between mitochondrial stress and SG assembly is not well understood.

Purpose of the Study:

• To investigate the relationship between malonate-induced mitochondrial stress and stress granule formation.
• To elucidate the molecular pathways involved in this process.

Main Methods:

• Treatment of cells with malonate.
• Assessment of mitochondrial function (ROS, Δψm, ATP levels).
• Analysis of stress granule assembly and protein phosphorylation (eIF2α, 4EBP1).
• Gene knockdown experiments (4EBP1).

Main Results:

• Malonate treatment induced mitochondrial stress, including increased ROS, reduced mitochondrial membrane potential (Δψm), and decreased ATP levels.
• Malonate also triggered stress granule formation and inhibited translation.
• Phosphorylation of eIF2α and 4EBP1 was affected by mitochondrial dysfunction.
• Knockdown of 4EBP1, but not eIF2α, impacted stress granule formation.
• Increased ATP levels exacerbated malonate-induced stress granule aggregation.

Conclusions:

• Malonate triggers mitochondrial stress, leading to the assembly of non-canonical cellular stress granules.
• The 4EBP1 pathway plays a crucial role in mediating malonate-induced stress granule formation.
• This study reveals a novel connection between mitochondrial dysfunction and stress granule dynamics.