Secretome analysis of C-mannosyltransferase-deficient hiPSCs

C-mannosylation is a modification of tryptophan residues with a single mannose effecting protein folding, secretion and/or function. To date, only few proteins have been proven to be C-mannosylated and studies aiming at global assessment of protein C-mannosylation from cells or tissues are scarce. In order to interrogate the C-mannosylome of human induced pluripotent stem cells (hiPSCs), we made use of the common finding that C-mannosylation is important for protein secretion. Thus we compared the secretomes of C-mannosyltransferase-deficient DPY19L1 and DPY19L3 mutants to their parental wild-type hiPSCs by mass-spectrometry-based quantitative proteomics. Secretion of numerous proteins was reduced in the mutants.