TOPORS functions as a SUMO-1 E3 ligase for chromatin-modifying proteins.
TOPORS is the first example of a protein with both ubiquitin and SUMO-1 E3 ligase activity and has been implicated as a tumor suppressor in several different malignancies. To gain insight into the cellular role of TOPORS, a proteomic screen was performed to identify candidate sumoylation substrates. The results indicate that many of the putative substrates are involved in chromatin modification or transcriptional regulation. Transfection studies confirmed mammalian Sin3A as a sumoylation substrate for TOPORS. These findings suggest that TOPORS may function as a tumor suppressor by regulating mSin3A and other proteins involved in chromatin modification.
Pungaliya
Pooja
P
Department of Pharmacology, The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 195 Little Albany Street, New Brunswick, New Jersey 08901, USA.
Kulkarni
Diptee
D
Park
Hye-Jin
HJ
Marshall
Henderson
H
Zheng
Haiyan
H
Lackland
Henry
H
Saleem
Ahamed
A
Rubin
Eric H
EH
D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D025842:SUMO-1 Protein / Q000378:metabolism*; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D014162:Transfection; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*