May function in recognizing stalled ribosomes, interact with stem-loop structures in stalled mRNA molecules, and effect endonucleolytic cleavage of the mRNA. May play a role in the release non-functional ribosomes and degradation of damaged mRNAs. Has endoribonuclease activity. Monomer. The N-terminal domain has the RNA-binding Sm fold. It harbors the endoribonuclease activity. Belongs to the eukaryotic release factor 1 family. Pelota subfamily.