E3 SUMO protein ligase (IPR027229)

Short name: SIZ1/SIZ2/Pli1/Gei17

Overlapping homologous superfamilies


Family relationships



SUMO proteins are ubiquitin like proteins that are covalently attached to and detached from other proteins in cells to modify their function. SUMO is first activated in an ATP-dependent reaction by formation of a thioester bond with an E1 (SUMO-activating) enzyme and then transferred to the SUMO conjugating (E2) enzyme Ubc9. Ubc9 catalyses the formation of an isopeptide bond between the C-terminal of SUMO and the amino group of lysine in the target protein. Sumoylated proteins can be targeted for different cellular processes, such as nuclear transport, transcriptional regulation, apoptosis, and protein stability [PMID: 12383504].

Proteins in this entry including SIZ1 and SIZ2 (also known as Nfi1) from budding yeast, Pli1 from fission yeast and Gei-17 from Caenorhabditis elegans. They may act as E3 ligases mediating SUMO attachment to other proteins. SIZ1 is required for sumoylation of septins [PMID: 11587849]. SIZ2 is involved in chromatin anchoring and maintenance of proper telomere length [PMID: 21666682]. Gei-17 suppresses checkpoint activation in response to DNA damage [PMID: 16549501]. Pli1 regulates recombination within the heterochromatin repeats via extension sumoylation and is involved in the maintenance of the centromere and in telomere length [PMID: 15359282].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0019789 SUMO transferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.