Activation of Gαq sequesters specific transcripts into Ago2 particles

Abstract Hormones and neurotransmitters can activate the Gαq / phospholipase Cβ1 (PLCβ1) signaling system eliciting cellular calcium responses. PLCβ1 also prevents the aggregation of ribosomal and RNA proteins into stress granules, which are halted translation complexes that form in response to cellular stress. Activation of Gαq promotes PLCβ1association releasing bound proteins and promoting the formation of stress granules. However, the cellular impact of stress granules formed from routine Gαq protein signaling is unknown. Here, we have characterized Ago2 stress granules formed in response to Gαq activation in a neuronal-like cell line. We find these stress granule have a distinct protein composition, and unlike stress granules formed under heat stress, contain only two mRNA transcripts, chromogranin B, which is involved in secretory function, and ATP synthase 5f1b, which is required for ATP synthesis. Our studies show an unexpected pathway where Gαq/PLCβ regulates the translation of specific proteins.