 In some species there is a single member of this family which gives the mature product mir-33.In humans there are two members of this family called mir-33a and mir-33b, which are located in intronic regions within two protein-coding genes for Sterol regulatory element-binding proteins (SREBP-2 and SREBP-1) respectively.miR-33 plays a role in lipid metabolism; it downregulates a number of ABC transporters, including ABCA1 and ABCG1, which in turn regulate cholesterol and HDL generation.