A stress-dependent SUMO4 sumoylation of its substrate proteins.
Here we performed studies to demonstrate SUMO4 maturation process. Unlike other SUMO proteins, cells under physiological condition mediate a rapid degradation for SUMO4. However, when cells under stressed condition, SUMO4 can be matured by the stress-induced endogenous hydrolase and be able to covalently conjugate to its substrate proteins. Furthermore, we failed to obtain evidence supporting a role for proline-90 unique to SUMO4 in its activation and functionality. Both wild-type SUMO4 and SUMO4-P90Q can be hydrolyzed by the stressed RAW264.7 cell lysates, and no significant functional difference between SUMO4, SUMO4-P90Q, and SUMO4-GG (matured form) was observed as determined by luciferase assay. However, the C-terminal di-glycine motif, a prerequisite for sumoylation, is necessary for SUMO4 to exert its functional activity. These data not only confirmed our previous published data, but also provided additional evidence suggesting a role for SUMO4 sumoylation in the regulation of intracellular stress.
Wei
Wenzhong
W
Center for Biotechnology and Genomic Medicine, Medical College of Georgia, 1120 15th Street, CA4098, Augusta, GA 30912, USA.
Yang
Ping
P
Pang
Junfeng
J
Zhang
Shu
S
Wang
Ying
Y
Wang
Mong-Heng
MH
Dong
Zheng
Z
She
Jin-Xiong
JX
Wang
Cong-Yi
CY
D000818:Animals; D002460:Cell Line; D006801:Humans; D051379:Mice; D011392:Proline / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*; D013379:Substrate Specificity
C489647:SUMO4 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; D011392:Proline