Low complexity RGG-motif sequence is required for Processing body (P-body) disassembly.

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Processing bodies (P-bodies) are crucial cellular structures regulating mRNA fate, influencing translation and decay.
• The precise mechanisms governing P-body dynamics, particularly disassembly, remain incompletely understood.
• Identifying factors that control P-body assembly and disassembly is essential for understanding gene expression regulation.

Purpose of the Study:

• To identify novel factors involved in P-body disassembly.
• To elucidate the molecular mechanism by which Sbp1 influences P-body dynamics.
• To investigate the potential role of Sbp1 in the regulation of disease-associated protein aggregates.

Main Methods:

• Genetic analysis of P-body disassembly in yeast mutants lacking Sbp1 (Δsbp1).
• Biochemical assays using purified proteins to study Sbp1-Edc3 interactions.
• In vitro assembly assays with purified Edc3, RNA, NADH, and Sbp1 or its mutants.
• Analysis of human EWSR1 protein aggregation in yeast models.

Main Results:

• Sbp1 acts as a P-body disassembly factor, with disassembly defective in Δsbp1 cells.
• The RGG-motif of Sbp1 is essential for its function in P-body disassembly.
• Sbp1 directly interacts with Edc3, competing with Edc3 self-interaction and inhibiting Edc3 assembly.
• Absence of Sbp1 leads to persistent aggregates of human EWSR1 protein, causing growth defects upon EWSR1 overexpression.

Conclusions:

• Sbp1 is a critical regulator of P-body disassembly, functioning through interaction with Edc3.
• Sbp1's role in protein aggregate management extends to disease-relevant proteins like EWSR1.
• These findings highlight Sbp1 as a potential target for modulating P-body dynamics and protein aggregation in disease contexts.