Enables 2-acylglycerol O-acyltransferase activity and diacylglycerol O-acyltransferase activity. Acts upstream of or within diacylglycerol biosynthetic process. Located in endoplasmic reticulum and membrane. Orthologous to human MOGAT1 (monoacylglycerol O-acyltransferase 1). [provided by Alliance of Genome Resources, Apr 2022]