High impact information on smt3

• Post-translational modification of proteins by the ubiquitin-like molecule SUMO (sumoylation) regulates their subcellular localization and affects their functional properties in vitro, but the physiological function of sumoylation in multicellular organisms is largely unknown [1].
• SUMO modification of Sp3 occurs at a single lysine located between the second glutamine-rich activation domain and the DNA-binding domain [2].
• We demonstrate that Tramtrack 69 (Ttk69), a repressor of neuronal differentiation, is a bona fide in vivo substrate for dSmt3 conjugation [3].
• Altogether, these data indicate a high conservation of the Smt3 conjugation pathway and further suggest that this mechanism may play a role in the transcriptional regulation of cell differentiation in Drosophila flies [3].
• In the presence of Ulp1, most SUMO conjugates reside in the nucleus [4].

Biological context of smt3

• Mutations in Star and l(2)43Bb had no significant effect upon the lambdatop eggshell defect whereas smt3 and dock alleles significantly suppressed the lambdatop phenotype [5].
• In older embryos, DmUba2 and DmSmt3 are both concentrated in the nuclei during interphase but dispersed throughout the cells during mitosis, with DmSmt3 also enriched on the chromosomes during mitosis [6].
• The other required components of the system, Drosophila Aos1 and SUMO-1 (DmAos1 and DmSUMO-1), were identified in expressed sequence tag data base searches [7].
• SUMO enhances vestigial function during wing morphogenesis [8].
• Using a systematic approach toward modifier gene discovery, we have found five chromosome I genes that modify the mus-101 RNAi phenotype, and we go on to show that one of them encodes an E3 SUMO ligase that promotes SUMO modification of MUS-101 in vitro [9].

Anatomical context of smt3

• DmSUMO-1 conjugation occurs in all developmental stages of Drosophila and in the adult central nervous system [7].
• We hypothesize that, as a component of the nuclear pore complex, Ulp1 may prevent proteins from leaving the nucleus with SUMO still attached [4].

Associations of smt3 with chemical compounds

• The conjugation of the ubiquitin-like protein SUMO to lysine side chains plays widespread roles in the regulation of nuclear protein function [8].

Physical interactions of smt3

• We have found that DmUbc9 binds and conjugates Drosophila Smt3 (DmSmt3) to Dorsal [10].

Other interactions of smt3

• We did not observe any concentration of DmUba2 at sites where the septins are concentrated, and we could not detect DmSmt3 modification of the three Drosophila septins tested [6].
• We found that at least one isoform of Drosophila neuronal CaMKII is conjugated to DmSUMO-1 in vivo [7].
• The effect of DmUbc9 on Dorsal activity was potentiated by the overexpression of DmSmt3 [10].
• We found that flies heterozygous for a deficiency uncovering vestigial (vg) and mutations in any of several genes encoding components of the SUMO conjugation machinery exhibit severe wing notching [8].

References