C‐mannosylation promotes ADAMTS1 activation and secretion in human testicular germ cell tumor NEC8 cells

C ‐mannosylation is a protein glycosylation that regulates the functions of target proteins. Although it has been reported that a disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1), an important spermatogenesis factor, is C ‐mannosylated, the roles of C ‐mannosylation in ADAMTS1 in testicular cells are still unclear. In this study, we found that ADAMTS1 is C ‐mannosylated at Trp 562 and Trp 565 in testis germ NEC8 cells. To determine the roles of C ‐mannosylation in ADAMTS1, we established cells expressing a C ‐mannosylation‐defective ADAMTS1, in which C ‐mannosylated tryptophan residues were replaced with phenylalanine residues (ADAMTS1/2WF). Processing and secretion of ADAMTS1/2WF were both inhibited compared to those of wild‐type. Moreover, wild‐type ADAMTS1 degraded aggrecan, whereas ADAMTS1/2WF could not. These results indicate the impact of C ‐mannosylation on ADAMTS1 function.