SMT3 suppressor of mif two 3 homolog 2 (S. cerevisiae)
SMT3, yeast, homolog 2
Ubiquitin like protein SMT3B
Ubiquitin-like protein SMT3A
FunctionUbiquitin-like protein that can be covalently attached to proteins as a monomer or as a lysine-linked polymer. Covalent attachment via an isopeptide bond to its substrates requires prior activation by the E1 complex SAE1-SAE2 and linkage to the E2 enzyme UBE2I, and can be promoted by an E3 ligase such as PIAS1-4, RANBP2 or CBX4. This post-translational modification on lysine residues of proteins plays a crucial role in a number of cellular processes such as nuclear transport, DNA replication and repair, mitosis and signal transduction. Polymeric SUMO2 chains are also susceptible to polyubiquitination which functions as a signal for proteasomal degradation of modified proteins.
Tissue specificityBroadly expressed.
Sequence similaritiesBelongs to the ubiquitin family. SUMO subfamily. Contains 1 ubiquitin-like domain.
Post-translational modificationsPolymeric chains can be formed through Lys-11 cross-linking. Polymeric SUMO2 chains undergo 'Lys-6'-, 'Lys-11'-, 'Lys-48'- and 'Lys-63'-linked polyubiquitination by RNF4. Cleavage of precursor form by SENP1 or SENP2 is necessary for function.