Diglyceride acyltransferase that uses fatty acyl-CoA as substrate (PubMed:15671038). Particularly active with oleate as a substrate (PubMed:15671038). Has no wax synthase activity to produce wax esters (PubMed:15671038). Able to use 1-monoalkylglycerol (1-MAkG) as an acyl acceptor for the synthesis of monoalkyl-monoacylglycerol (MAMAG) (PubMed:28420705). (9Z)-octadecenoyl-CoA + 1,2-di-(9Z-octadecenoyl)-sn-glycerol = 1,2,3-tri-(9Z-octadecenoyl)-glycerol + CoA (9Z)-octadecenoyl-CoA + 1-O-(9Z-octadecenyl)-glycerol = 1-O-(9Z-octadecenyl)-mono-(9Z-octadecenoyl)-glycerol + CoA (9Z)-octadecenoyl-CoA + 1-(9Z-octadecenoyl)-glycerol = 1,2-di-(9Z-octadecenoyl)-glycerol + CoA Expressed in all tissues tested except pancreas. Belongs to the diacylglycerol acyltransferase family.