biostudies-literatureTakeuchi HHHS | NIH | National Institute of General Medical SciencesNIGMS NIH HHSE8395-E8402https://www.ebi.ac.uk/biostudies/studies/S-EPMC6130362biostudies-literatureUnknown115(36)The Notch-signaling pathway is normally activated by Notch-ligand interactions. A recent structural analysis suggested that a novel <i>O</i>-linked hexose modification on serine 435 of the mammalian NOTCH1 core ligand-binding domain lies at the interface with its ligands. This serine occurs between conserved cysteines 3 and 4 of Epidermal Growth Factor-like (EGF) repeat 11 of NOTCH1, a site distinct from those modified by protein <i>O</i>-glucosyltransferase 1 (POGLUT1), suggesting that a different enzyme is responsible. Here, we identify two novel protein <i>O</i>-glucosyltransferases, POGLUT2 and POGLUT3 (formerly KDELC1 and KDELC2, respectively), which transfer <i>O</i>-glucose (<i>O</i>-Glc) from UDP-Glc to serine 435. Mass spectrometric analysis of NOTCH1 produced in HEK293T cells lacProceedings of the National Academy of Sciences of the United States of AmericaTwo novel protein <i>O</i>-glucosyltransferases that modify sites distinct from POGLUT1 and affect Notch trafficking and signaling.PMC6130362T32 GM107004GM061126R01 GM061126Takeuchi MHaltiwanger RSSchneider MHandford PATakeuchi HWilliamson DBIto AfalseTwo novel protein <i>O</i>-glucosyltransferases that modify sites distinct from POGLUT1 and affect Notch trafficking and signaling.The Notch-signaling pathway is normally activated by Notch-ligand interactions. A recent structural analysis suggested that a novel <i>O</i>-linked hexose modification on serine 435 of the mammalian NOTCH1 core ligand-binding domain lies at the interface with its ligands. This serine occurs between conserved cysteines 3 and 4 of Epidermal Growth Factor-like (EGF) repeat 11 of NOTCH1, a site distinct from those modified by protein <i>O</i>-glucosyltransferase 1 (POGLUT1), suggesting that a different enzyme is responsible. Here, we identify two novel protein <i>O</i>-glucosyltransferases, POGLUT2 and POGLUT3 (formerly KDELC1 and KDELC2, respectively), which transfer <i>O</i>-glucose (<i>O</i>-Glc) from UDP-Glc to serine 435. Mass spectrometric analysis of NOTCH1 produced in HEK293T cells lac2018-01-01T00:00:00Z2018 Sep2026-06-10T05:41:06.262Z2019-08-04T08:13:26ZS-EPMC61303623012700110.1073/pnas.1804005115