Constructing P-bodies

Putting together a P-body requires both building blocks and glue. Decker et al. now show that a yeast mRNA decapping activator protein contributes to both jobs: it forms part of the building block and also helps to glue those blocks together.

P-bodies are cytoplasmic granules that contain unused mRNAs with their associated proteins (complexes known as mRNPs) and mRNA decay factors. Much of the team's previous work investigated how the mRNPs—which form the building blocks—affect mRNA function. How and why mRNPs assemble into P-bodies was unclear.

The new work further reveals the inner organization of the building blocks by identifying how an mRNA decapping activator, called Edc3p, brings together the mRNP components. Edc3p bound to two protein complexes that associated with P-body–bound mRNAs: a complex of 5′ decapping enzymes and a complex of other...