Probable C-mannosyltransferase that mediates C-mannosylation of tryptophan residues on target proteins.
Required during spermatogenesis for sperm head elongation and acrosome formation (, ). Also plays a role in acrosome attachment to the nuclear envelope (By similarity).
Subcellular locations: Nucleus inner membrane
Colocalizes with DPY19L2 at the inner nuclear membrane.
Widely expressed with high expression in testis. Not detectable in ejaculated sperm (at protein level).