Essential acyltransferase that catalyzes the terminal and only committed step in triacylglycerol synthesis by using diacylglycerol and fatty acyl CoA as substrates. Required for synthesis and storage of intracellular triglycerides (By similarity). Probably plays a central role in cytosolic lipid accumulation. In liver, is primarily responsible for incorporating endogenously synthesized fatty acids into triglycerides (By similarity). Functions also as an acyl-CoA retinol acyltransferase (ARAT) (By similarity). Also able to use 1-monoalkylglycerol (1-MAkG) as an acyl acceptor for the synthesis of monoalkyl-monoacylglycerol (MAMAG) (By similarity). a 1,2-diacyl-sn-glycerol + an acyl-CoA = a triacyl-sn-glycerol + CoA all-trans-retinol + an acyl-CoA = an all-trans-retinyl ester + CoA (9Z)-octadecenoyl-CoA + 2-(9Z-octadecenoyl)-glycerol = 1,2-di-(9Z-octadecenoyl)-sn-glycerol + CoA (9Z)-octadecenoyl-CoA + 1,2-di-(9Z-octadecenoyl)-sn-glycerol = 1,2,3-tri-(9Z-octadecenoyl)-glycerol + CoA all-trans-retinol + hexadecanoyl-CoA = all-trans-retinyl hexadecanoate + 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 1,2-di-(9Z-octadecenoyl)-sn-glycerol + hexadecanoyl-CoA = 1,2-di-(9Z)-octadecenoyl-3-hexadecanoyl-sn-glycerol + CoA (9Z)-octadecenoyl-CoA + 1,3-di-(9Z-octadecenoyl)-glycerol = 1,2,3-tri-(9Z-octadecenoyl)-glycerol + CoA (9Z)-octadecenoyl-CoA + 2,3-di-(9Z)-octadecenoyl-sn-glycerol = 1,2,3-tri-(9Z-octadecenoyl)-glycerol + CoA 2-(9Z-octadecenoyl)-glycerol + hexadecanoyl-CoA = 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycerol + CoA Inhibited by niacin. Glycerolipid metabolism; triacylglycerol biosynthesis. Forms multimeric complexes consisting of several DGAT2 subunits (By similarity). Interacts with SLC27A1 and this interaction is enhanced in the presence of ZFYVE1 (By similarity). Belongs to the diacylglycerol acyltransferase family.