Monoclonal antibody‐based systematic identification of SUMO1‐modification sites reveals TFII‐I SUMOylation is involved in tumor growth

Abstract

AbstractSUMOylation plays an essential role in diverse physiological and pathological processes. Identification of wild‐type SUMO1‐modification sites by mass spectrometry is still challenging. In this study, we produced a monoclonal SUMO1C‐K antibody recognizing SUMOylated peptides and proposed an efficient streamline for identification of SUMOylation sites. We identified 471 SUMOylation sites in 325 proteins from five raw data. These identified sites exhibit a high positive rate when evaluated by mutation‐verified SUMOylation sites. We identified many SUMOylated proteins involved in mitochondrial metabolism and non‐membrane‐bounded organelles formation. We proposed a SUMOylation motif, ΨKXD/EP, where proline is required for efficient SUMOylation. We further revealed SUMOylation of TFII‐I was stimulated by growth signals and was required for nucleus‐localization of p‐ERK1/2. Mutation of SUMOylation sites of TFII‐I suppressed tumor cell growth in vitro and in vivo. Taken together, we provided a strategy for personalized identification of wild‐type SUMO1‐modification sites and revealed the physiological significance of TFII‐I SUMOylation in this study.