Fig. 3.

C-mannosylation of UNC5A TSRs in triple knockouts reexpressing single DPY19 enzymes. (A) TSR1 EIC profiles. Triple knockouts (red graph) showed only the unmodified peptide and no C-mannosylation. In cells overexpressing DPY19L1 (blue graph) the most abundant glycoforms had two mannoses and fucosylation (with or without additional glucose), whereas no trimannosylated forms were detected. Cells overexpressing DPY19L3 exclusively showed monomannosylated species. (B) TSR2 EIC profiles. In TSR2, both DPY19L1 and DPY19L3 can mannosylate the first two tryptophans (Left). C-mannosylated W3 (Right) was predominantly detected in triple knockout cells reexpressing DPY19L3. (C) Proposed substrate specificity of C. elegans DPY-19 and mammalian DPY19L1 and -L3 on the WxxWxxW motif of TSRs.