From the analysis of primary MM and CD34+ MDS cells treated with IMiD, it was found that CRBN functions via a ubiquitin-independent chaperone-like mechanism to mediate the folding and maturation of CD147 and MCT1 proteins, thereby allowing the activation of the CD147–MCT1 transmembrane complex. The gene discussed is SLC16A1; the disease is myelodysplastic syndrome.