This gene encodes a membrane-associated protein that adds the third glucose residue to the lipid-linked oligosaccharide precursor for N-linked glycosylation. That is, it transfers the terminal glucose from dolichyl phosphate glucose (Dol-P-Glc) onto the lipid-linked oligosaccharide Glc2Man9GlcNAc(2)-PP-Dol. The rat protein homolog was shown to specifically modulate the gating function of the rat neuronal ether-a-go-go (EAG) potassium ion channel. [provided by RefSeq, Jan 2010].