Upon stress, cytoplasmic mRNA is sequestered to insoluble ribonucleoprotein 
(RNP) granules, such as the stress granule (SG). Partially due to the belief 
that translationally suppressed mRNAs are recruited to SGs in bulk, 
stress-induced dynamic redistribution of mRNA has not been thoroughly 
characterized. Here, we report that endoplasmic reticulum (ER) stress targets 
only a small subset of translationally suppressed mRNAs into the insoluble RNP 
granule fraction (RG). This subset, characterized by extended length and 
adenylate-uridylate (AU)-rich motifs, is highly enriched with genes critical for 
cell survival and proliferation. This pattern of RG targeting was conserved for 
two other stress types, heat shock and arsenite toxicity, which induce distinct 
responses in the total cytoplasmic transcriptome. Nevertheless, stress-specific 
RG-targeting motifs, such as guanylate-cytidylate (GC)-rich motifs in heat 
shock, were also identified. Previously underappreciated, transcriptome 
profiling in the RG may contribute to understanding human diseases associated 
with RNP dysfunction, such as cancer and neurodegeneration.