In fact, DDRGK1 (also known as C20orf116 and UFBP1) was the first characterized substrate of UFM1, and soon emerged as an E3 cofactor, whose UFMylation is not necessary for E3 complex assembly, but could alter the UFMylation of other substrates, such as ASC1, a nuclear receptor co-activator vital for breast cancer development (14, 28) (Table 1). This evidence concerns the gene TRIP4 and breast cancer.