Ubiquitin-like protein that can be covalently attached to proteins as a monomer or as a lysine-linked polymer. Regulates the life cycle of promyelocytic leukemia nuclear bodies (PML-NBs). PolySUMO1P1/SUMO5 conjugation on 'Lys-160' of PML facilitates recruitment of PML-NB components, which enlarges PML-NB. SUMO1P1/SUMO5 also increases polySUMO2/3 conjugation of PML, resulting in RNF4- mediated disruption of PML-NBs. . This is the function of ENSG00000241721 (SUMO1P1, SUMO1 pseudogene 1).