The ribosome as a platform to coordinate mRNA decay

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Messenger RNA (mRNA) homeostasis is crucial for cellular function, balancing transcription and decay.
• Traditionally, free mRNA was considered the primary target for degradation.
• Emerging evidence highlights the ribosome's significant role in mRNA decay coordination.

Purpose of the Study:

• To review the mechanisms by which ribosomes facilitate mRNA decay.
• To explore the role of translational fidelity and errors in triggering decay pathways.
• To provide a comprehensive overview of the ribosome's function in mRNA stability.

Main Methods:

• Literature review of recent advances in mRNA decay and ribosome function.
• Analysis of molecular mechanisms involving key protein complexes (e.g., Ccr4-Not, exosome).
• Discussion of mRNA quality control pathways (nonstop decay, no-go decay).

Main Results:

• Ribosomes actively license and execute mRNA decay, challenging previous models.
• Translational fidelity, nonoptimal codons, and ribosome collisions trigger specific decay pathways.
• Exonucleases (Xrn1, Ski-exosome) associate directly with ribosomes, supporting their regulatory role.

Conclusions:

• Ribosomes are central hubs coordinating mRNA decay and stability.
• The ribosome's role extends beyond translation to encompass critical regulatory functions in gene expression.
• Understanding these mechanisms provides insight into cellular mRNA homeostasis.