Endoplasmic reticulum membrane-bound UDP-glucose:dolichyl-phosphate glucosyltransferase involved in protein N-linked glycosylation. a dolichyl phosphate + UDP-alpha-D-glucose = a dolichyl beta-D-glucosyl phosphate + UDP Protein modification; protein glycosylation. Its interaction with the substrate UDP-glucose may occur at the cytoplasmic side of the ER, whereas the steps utilizing dolichyl beta-D-glucosyl phosphate take place in the lumen of the ER. Leads to a loss of UDP-glucose:dolichyl-phosphate glucosyltransferase activity and a concomitant underglycosylation of carboxypeptidase Y. Present with 5800 molecules/cell in log phase SD medium. Belongs to the glycosyltransferase 2 family.