Research ResourceBiochemistry

Comparative Proteomic Analysis Identifies a Role for SUMO in Protein Quality Control

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Science Signaling  21 Jun 2011:
Vol. 4, Issue 178, pp. rs4
DOI: 10.1126/scisignal.2001484

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SUMO and the Proteasome

Members of the family of ubiquitin-like posttranslational protein modifiers, such as small ubiquitin-like modifiers (SUMOs), share structural similarity with ubiquitin and form conjugates with target proteins to regulate many eukaryotic cellular functions. Noting that inhibition of the proteasome results in the accumulation of SUMO-conjugated proteins, Tatham et al. used mass spectrometric analysis of purified proteins to perform a system-wide analysis of protein SUMOylation in HeLa cells exposed to the proteasomal inhibitor MG132. Changes in SUMOylation were similar to those known to be triggered by heat stress and seemed to be secondary to the accumulation of misfolded proteins. In addition, SUMO-2 and ubiquitin were exchanged among substrates during proteasome inhibition. Together, these findings suggest SUMO proteins are involved in the response to the accumulation of misfolded proteins in cells.