SUMO-2/3 conjugates accumulating under heat shock or MG132 treatment result largely from new protein synthesis.
Small ubiquitin-related modifiers 1, 2 and 3 (SUMO-1, -2, -3), members of the ubiquitin-like protein family, can be conjugated to various cellular proteins. Conjugates of SUMO-2 and SUMO-3 (SUMO-2/3) accumulate in cells exposed to various stress stimuli or to MG132 treatment. Although the proteins modified by SUMO-2/3 during heat shock or under MG132 treatment have been identified, the significance of this modification remains unclear. Our data show that the inhibition of translation by puromycin or cycloheximide blocks both the heat shock and MG132 induced accumulation of SUMO-2/3 conjugates in HEK 293T and U2OS cells. However, the heat shock induced accumulation of SUMO-2/3 conjugates was restored by proteasome inhibition, which suggests that the inhibition of translation did not abolish SUMOylation itself. Furthermore, we show that some of the proteins truncated due to the treatment by low concentration of puromycin are SUMOylated in HEK 293T cells. We suggest that the SUMO-2/3 conjugates accumulating under the heat shock or MG132 treatment result largely from new protein synthesis and that portion of them is incorrectly folded.
Department of Biochemistry, Institute of Chemical Technology, Prague, Czech Republic.
Markéta
M
Castorálová
Dagmar
D
Březinová
Martin
M
Svéda
Jan
J
Lipov
Tomáš
T
Ruml
Zdeněk
Z
Knejzlík
D016227:Benzoquinones / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D057809:HEK293 Cells; D006367:HeLa Cells; D018869:Heat-Shock Response / Q000187:drug effects*; D006801:Humans; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D007976:Leupeptins / Q000494:pharmacology*; D008954:Models, Biological; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors; D014176:Protein Biosynthesis / Q000187:drug effects*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011691:Puromycin / Q000494:pharmacology; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*; D058207:Sumoylation / Q000187:drug effects; D014452:Ubiquitins / Q000378:metabolism*
D016227:Benzoquinones; D047029:Lactams, Macrocyclic; D007976:Leupeptins; D061988:Proteasome Inhibitors; D011500:Protein Synthesis Inhibitors; C117909:SUMO2 protein, human; C492189:SUMO3 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; D014452:Ubiquitins; D011691:Puromycin; C112765:tanespimycin; D003513:Cycloheximide; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde