mRNA-Scaffolded Cytoplasmic Compartments

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• The cytoplasm of vertebrate cells is organized into distinct compartments, including messenger RNA (mRNA)-scaffolded condensates.
• These condensates, such as TIS granules and the FXR1 network, serve as specialized environments for translation, protein folding, and cellular signaling.
• While all mRNAs are involved in protein synthesis, only specific mRNAs with long, multivalent 3' untranslated regions (UTRs) function as scaffolds for these condensates.

Purpose of the Study:

• To review the discovery and assembly principles of cytoplasmic mRNA-scaffolded mesh-like compartments.
• To discuss the biological roles of these compartments in cellular processes.
• To highlight the essential functions of mRNAs in cytoplasmic organization.

Main Methods:

• This review synthesizes existing research on mRNA-scaffolded condensates.
• It examines the structural characteristics of scaffold mRNAs, particularly their 3' UTRs.
• The review discusses the functional implications of these condensates in protein biosynthesis and signaling.

Main Results:

• Scaffold mRNAs, distinguished by long and multivalent 3' UTRs, are crucial for forming irregular, network-like mesh structures.
• These mesh-like condensates act as critical folding environments, with their multivalent 3' UTRs functioning as cotranslational chaperones for proteins with intrinsically disordered regions.
• mRNA-mediated proximity within these compartments also enhances post-translational signaling reactions.

Conclusions:

• Messenger RNAs play a fundamental role in organizing cellular cytoplasm through the formation of functional condensates.
• These mRNA-scaffolded compartments are vital for efficient protein biosynthesis, proper protein folding, and effective cellular signaling.
• Understanding these structures provides new insights into cytoplasmic organization and mRNA's multifaceted roles in the cell.