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Modification of small ubiquitin‐related modifier 2 (SUMO2) by phosphoubiquitin in HEK293T cells
Author(s) -
Dongdem Julius T.,
Dawson Simon P.,
Layfield Robert
Publication year - 2021
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.202000234
Subject(s) - ubiquitin , hek 293 cells , parkin , phosphorylation , transfection , sumo protein , biology , ubiquitin ligase , microbiology and biotechnology , cell culture , biochemistry , genetics , gene , medicine , disease , pathology , parkinson's disease
Additional complexity in the post‐translational modification of proteins by ubiquitin is achieved by ubiquitin phosphorylation, for example within PINK1‐parkin mediated mitophagy. We performed a preliminary proteomic analysis to identify proteins differentially modified by ubiquitin in HEK293T, compared to phosphomimetic ubiquitin (Ser65Asp), and identified small ubiquitin‐related modifier 2 (SUMO2) as a candidate. By transfecting SUMO2 and its C ‐terminal–GG deletion mutant, along with phosphomimetic ubiquitin, we confirm that ubiquitin modifies SUMO2, rather than vice versa. Further investigations revealed that transfected SUMO2 can also be conjugated by endogenous phospho‐Ser65‐(poly)ubiquitin in HEK293T cells, pointing to a previously unappreciated level of complexity in SUMO2 modification, and that unanchored (substrate‐free) polyubiquitin chains may also be subject to phosphorylation.