The article by Ujwal Sheth and Roy Parker investigates the localization and function of processing bodies (P bodies) in yeast. They provide evidence that mRNA decapping and 5' to 3' degradation occur in discrete cytoplasmic foci called P bodies. Key findings include: 1. **Protein Concentration in P Bodies**: Proteins involved in decapping, such as Dcp1p, Dcp2p, Lsm1p, Pat1p, and Dhh1p, are concentrated in P bodies. 2. **Inhibition of mRNA Turnover**: Inhibiting mRNA turnover before decapping leads to a loss of P bodies, while inhibiting turnover at or after decapping increases the abundance and size of P bodies. 3. ** Localization of mRNA Degradation Intermediates**: mRNA degradation intermediates are localized to P bodies, suggesting that P bodies are critical sites for mRNA decay. 4. **Dynamic Relationship Between Translation and Decapping**: The size and number of P bodies reflect the flux of mRNAs undergoing decapping, indicating that P bodies are dynamic sites of mRNA decay. 5. **Model for mRNA Metabolism**: The study proposes a model where mRNAs exist in two functional states: one in polysomes and one in non-translating pools (P bodies), with transitions between these states regulated by translation status. These findings highlight the importance of P bodies in the regulation of mRNA turnover and suggest that they may serve as specific sites for mRNA decay and storage. The authors also discuss the potential conservation of P body-like structures in mammalian cells and the possibility of additional functions in cytoplasmic mRNA biology.The article by Ujwal Sheth and Roy Parker investigates the localization and function of processing bodies (P bodies) in yeast. They provide evidence that mRNA decapping and 5' to 3' degradation occur in discrete cytoplasmic foci called P bodies. Key findings include: 1. **Protein Concentration in P Bodies**: Proteins involved in decapping, such as Dcp1p, Dcp2p, Lsm1p, Pat1p, and Dhh1p, are concentrated in P bodies. 2. **Inhibition of mRNA Turnover**: Inhibiting mRNA turnover before decapping leads to a loss of P bodies, while inhibiting turnover at or after decapping increases the abundance and size of P bodies. 3. ** Localization of mRNA Degradation Intermediates**: mRNA degradation intermediates are localized to P bodies, suggesting that P bodies are critical sites for mRNA decay. 4. **Dynamic Relationship Between Translation and Decapping**: The size and number of P bodies reflect the flux of mRNAs undergoing decapping, indicating that P bodies are dynamic sites of mRNA decay. 5. **Model for mRNA Metabolism**: The study proposes a model where mRNAs exist in two functional states: one in polysomes and one in non-translating pools (P bodies), with transitions between these states regulated by translation status. These findings highlight the importance of P bodies in the regulation of mRNA turnover and suggest that they may serve as specific sites for mRNA decay and storage. The authors also discuss the potential conservation of P body-like structures in mammalian cells and the possibility of additional functions in cytoplasmic mRNA biology.