The enzymes in this family are glycosyltransferases. PimE is involved in phosphatidylinositol mannoside (PIM) synthesis, a major class of glycolipids in all mycobacteria. PimE is a polyprenol-phosphate-mannose-dependent mannosyltransferase that transfers the fifth mannose of PIM. The family also includes alpha(1-->3) arabinofuranosyltransferase, invloved in the synthesis of of mycobacterial arabinogalactan.