Disease relevance of SUM1

• The heat-induced accumulation could be detected within 2 min from the start of a temperature upshift, suggesting that SUMO1/2 conjugation is one of the early plant responses to heat stress [1].

High impact information on SUM1

• We report the identification and functional analysis of AtSUMO1, AtSUMO2, and AtSCE1a as components of the SUMO conjugation (sumoylation) pathway in Arabidopsis [2].
• Small ubiquitin-like modifier modulates abscisic acid signaling in Arabidopsis [2].
• In yeast-two hybrid assays, AtSUMO1/2 interacts specifically with a SUMO-conjugating enzyme but not with a ubiquitin-conjugating enzyme [2].
• Our results suggest a role for SUMO in the modulation of the ABA signal transduction pathway [2].
• Analysis of transgenic plants showed that overexpression of AtSUMO1/2 does not have any obvious effect in general plant development, but increased sumoylation levels attenuate abscisic acid (ABA)-mediated growth inhibition and amplify the induction of ABA- and stress-responsive genes such as RD29A [2].

Biological context of SUM1

• All these enzymes cleave AtSUMO1 and AtSUMO2 conjugates of ScPCNA, whereas only the putative bacterial virulence factor XopD is able to release AtSUMO3 [3].
• To analyze the substrate specificity of SUMO-conjugating and -deconjugating enzymes from Arabidopsis (Arabidopsis thaliana), we reconstituted its SUMOylation cascade in vitro and tested the capacity of this system to conjugate the Arabidopsis SUMO isoforms AtSUMO1, 2, and 3 to the model substrate ScPCNA from yeast (Saccharomyces cerevisiae) [3].
• SMT3A, a human homologue of the S. cerevisiae SMT3 gene, maps to chromosome 21qter and defines a novel gene family [4].
• This activity of ESD4 is prevented by mutations that affect the predicted active site of the protease or the cleavage site of the AtSUMO precursor [5].

Anatomical context of SUM1

• Mammalian RanGAP is bound to the nuclear pore by a mechanism involving the attachment of small ubiquitin-related modifier protein (SUMO) to its C terminus and the subsequent binding of the SUMOylated domain to the nucleoporin Nup358 [6].

Associations of SUM1 with chemical compounds

• The levels of SUMO1 and -2 conjugates but not SUMO3 conjugates increased substantially following exposure of seedlings to stress conditions, including heat shock, H(2)O(2), ethanol, and the amino acid analog canavanine [1].

Other interactions of SUM1

• Small ubiquitin-like modifier (SUMO) is a member of the superfamily of ubiquitin-like polypeptides that become covalently attached to various intracellular target proteins as a way to alter their function, location, and/or half-life [1].
• ESD4 shows a similar function to these proteases in vitro and processes the precursor of Arabidopsis SUMO (AtSUMO) to generate the mature form [5].
• Taken together, it appears that SIZ1-mediated conjugation of SUMO1 and SUMO2 to other intracellular proteins is essential in Arabidopsis, possibly through stress-induced modification of a potentially diverse pool of nuclear proteins [7].

Analytical, diagnostic and therapeutic context of SUM1

• An eight-gene family encoding the SUMO tag was discovered as were genes encoding the various enzymes required for SUMO processing, ligation, and release [1].

References