Inhibits programmed -1 ribosomal frameshifting (-1PRF) of a variety of mRNAs from viruses and cellular genes. Interacts with the -1PRF signal of target mRNA and translating ribosomes and causes premature translation termination at the frameshifting site (By similarity). May exhibit antiviral activity (By similarity). Interacts with PABPC1. Found in a complex with PABPC1 and LARP1. Interacts with ELAV1, MOV10 and UPF1; the interactions increase in presence of RNA. Binds to ribosomes. Interacts with GSPT1. Predominantly found in the cytoplasm. Belongs to the SHFL family.