Distinct and overlapping sets of SUMO-1 and SUMO-2 target proteins revealed by quantitative proteomics
Mol Cell Proteomics. 2006 Sep 25; [Epub ahead of print]
Alfred C. O. Vertegaal, Jens S. Andersen, Stephen C. Ogg, Ronald T. Hay, Matthias Mann, and Angus I. Lamond
Molecular Cell Biology, Leiden University Medical Center, Leiden 2300 RC
The SUMO family in vertebrates includes three different family members that are conjugated as post-translational modifications to target proteins. SUMO-2 and -3 are nearly identical, but differ substantially from SUMO-1. We have used quantitative proteomics to investigate the target protein preferences of SUMO-1 and SUMO-2. HeLa cells were established that stably express His6-SUMO-1 or His6-SUMO-2. These cell lines and control HeLa cells were labeled with stable arginine isotopes and His6-SUMOs were enriched from lysates using immobilized metal affinity chromatography. 53 SUMO conjugated proteins were identified, including 44 novel SUMO targets. 25 proteins were preferentially conjugated to SUMO-1, 19 were preferentially conjugated to SUMO-2 and 9 proteins were conjugated to both SUMO-1 and SUMO-2. SART1 was confirmed by immunoblotting to have both SUMO-1 and SUMO-2 linked forms at similar levels. SUMO-1 and SUMO-2 are thus shown to have distinct and overlapping sets of target proteins, indicating that SUMO-1 and SUMO-2 may have both redundant and non-redundant cellular functions. Interestingly, 14 of the 25 SUMO-1 conjugated proteins contain zinc fingers. While both SUMO family members play roles in many cellular processes, our data show that sumoylation is strongly associated with transcription since nearly one third of the identified target proteins are putative transcriptional regulators.
http://www.mcponline.org/cgi/content/abstract/M600212-MCP200v1
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