CELF1 and myotonic dystrophy type 1: Moreover, CUGBP1 has previously been identified in the proteome of SG core structures (Jain et al., 2016; Kuechler et al., 2020; Youn et al., 2018), which strengthens the evidence that the two DM1-associated proteins MBNL1 and CUGBP1 are core SG proteins.