mRNA accumulation is tightly regulated by diverse molecular pathways. The 
identification and characterization of enzymes and regulatory proteins involved 
in controlling the fate of mRNA offers the possibility to broaden our 
understanding of posttranscriptional gene regulation. Processing bodies (P 
bodies, PB) are cytoplasmic protein complexes involved in degradation and 
translational arrest of mRNA. Composition and dynamics of these subcellular 
structures have been studied in animal systems, yeasts and in the model plant 
Arabidopsis. Their assembly implies the aggregation of specific factors related 
to decapping, deadenylation, and exoribonucleases that operate synchronously to 
regulate certain mRNA targets during development and adaptation to stress. 
Although the general function of PB along with the flow of genetic information 
is understood, several questions still remain open. This review summarizes data 
on the composition, potential molecular roles, and biological significance of PB 
and potentially related proteins in Arabidopsis.