POP1 (gene)Ribonucleases P/MRP protein subunit POP1 is a protein that in humans is encoded by the POP1 gene.FunctionPOP1 is a protein subunit of two different small nucleolar ribonucleoprotein complexes: the endoribonuclease for mitochondrial RNA processing complex and the ribonuclease P complex. This protein is a ribonuclease that localizes to the nucleus and functions in pre-RNA processing.Clinical significancePOP1 is also an autoantigen in patients with connective tissue diseases. Mutations in the POP1 gene result in severe anauxetic dysplasia.InteractionsPOP1 has been shown to interact with POP4.