Small molecule proteolysis targeting chimeras (PROTACs) that target hRpn13 were used as chemical probes to identify in multiple myeloma cells, a DEUBAD-deleted hRpn13 fragment (hRpn13Pru) that cannot bind UCHL5 and has lost regulatory restrictions imposed by an inter-domain DEUBAD:Pru interaction11,28. Here, ADRM1 is linked to AL amyloidosis.