small ubiquitin-related modifier 5; SUMO-5; SUMO1 pseudogene 1; ubiquitin-like 2; ubiquitin-like 6 (SUMO1P1, SUMO5 ,,,, UBL2, UBL6)

Function

• ubiquitin-like protein
• 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
• cleavage of precursor form is necessary for function
• autosumoylated at Lys-18
• interacts with CBX4
• interacts with PIAS1
• found in a complex with SAE2
• interacts with UBE2I
• interacts with SP100
• interacts with HIPK2
• interactswith DAXX
• interacts with PML-RARA oncoprotein;
• PML-RARalpha outcompetes PML for SUMO1P1/SUMO5 conjugation

Structure

belongs to the ubiquitin family, SUMO subfamily

Compartment

• nucleus
• forms prominent non-membrane-bound structures in the nucleus

Expression

• high expression levels in testes & peripheral blood leukocytes
• also expressed in lung, placenta, liver, spleen & thymus Comparative biolgy:
• highly conserved among primate species,
• not detected in mice

Notes

• defined as a pseudogene by HGNC; hwever the existence of the functional protein is supported by the inhibition of its expression & its function using siRNAs specifically targeting SUMO1P1/SUMO5

More general terms

• nuclear protein

Database

• UniProt: http://www.uniprot.org/uniprot/G2XKQ0.html