Enables peptide binding activity. Involved in several processes, including cellular response to organonitrogen compound; cellular response to phorbol 13-acetate 12-myristate; and lactation. Located in membrane. Is active in synapse. Biomarker of Down syndrome. Orthologous to human RPLP0 (ribosomal protein lateral stalk subunit P0). [provided by Alliance of Genome Resources, Apr 2022]