In genetic engineering, the 2A peptides are used to cleave a longer peptide into two shorter peptides. The 2A peptides can be applied when the fused protein doesn’t work. Inserting the CDS of a 2A peptide into the fusing point or replacing the linker sequence with the CDS of a 2A peptide protein can cleave the fused protein into two separated peptides, rescuing the function of the two peptides.
2A peptides, when combined (or not) with the IRES elements, can make it possible to generate multiple separated peptides within a single transcript.