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small ubiquitin-related modifier 3; SUMO-3; ubiquitin-like protein SMT3A; SMT3 homolog 1; SUMO-2 (SUMO3, SMT3A, SMT3H1)

SUMO3 would appear to be identical with sentrin-3 & ubiquitin-like protein SMT3A [3] Function: - ubiquitin-like protein which can be covalently attached to target Lys either as a monomer or as a Lys-linked polymer - does not seem to be involved in protein degradation - may function as an antagonist of ubiquitin in the degradation process - plays a role in a number of cellular processes such as a) nuclear transport b) DNA replication & repair c) mitosis d) signal transduction - covalent attachment to its substrates requires prior activation by the E1 complex SAE1-SAE2 & linkage to the E2 enzyme UBE2I, & can be promoted by an E3 ligase such as PIAS1-4, RANBP2 or CBX4 - polymeric chains can be formed through Lys-11 cross-linking - cleavage of precursor form by SENP1, SENP2 or SENP5 is necessary for function - interacts with SAE2 & UBE2I - covalently attached to a number of proteins (putative) - targets of sumoylation by SUMO3 include: a) topoisomerase-2 [1] b) amyloid precursor protein (APP)* [2] 1] increased sumoylation with poly(SUMO)chains is associated with diminished A4-amyloid peptide production 2] SUMO3 immunoreactivity present in human brain may be associated with inhibition of APP proteolysis Structure: - belongs to the ubiquitin family, SUMO subfamily - contains 1 ubiquitin-like domain - SUMO2 & SUMO3 are 95% similar at the amino-terminus Compartment: cytoplasm Expression: - expressed predominantly in liver - presumably expressed in brain [2]

General

SUMO protein (small ubiquitin-related modifier)

Properties

SIZE: entity length = 103 aa MW = 12 kD COMPARTMENT: cytoplasm MOTIF: Ubiquitin-like {15-92}

Database Correlations

OMIM 602231 UniProt P55854 Entrez Gene 6612 Kegg hsa:6612

References

  1. Azuma Y et al, J Cell Bil 163:477, 2003 PMID: 14597774
  2. Li Y, Wang H, Wang S, Quon D, Liu YW, Cordell B. Positive and negative regulation of APP amyloidogenesis by sumoylation. Proc Natl Acad Sci U S A. 2003 Jan 7;100(1):259-64. Epub 2002 Dec 27. Erratum in: Proc Natl Acad Sci U S A. 2003 Jul 22;100(15):9102. PMID: 12506199
  3. Ye ET et al Ubiquitin-like proteins: new wines in new bottles. Gene 248:1, 2000 PMID: 10806345
  4. Wikipedia; Note: SUMO protein entry http://en.wikipedia.org/wiki/SUMO_protein