Biochem/physiol Actions
RNA binding motif protein 39 (RBM39; CAPERα, HCC1) degradation-inducing SPLAM (SPLicing inhibitor sulfonAMide).
Tasisulam (LY573636) is a SPLAM (SPLicing inhibitor sulfonAMide) that bridges RNA binding motif protein 39 (RBM39; CAPERα, HCC1) and DCAF15 for interaction, thereby promoting (CUL4-DDB1-DDA1-DCAF15) E3 ubiquitin ligase complex-mediated RBM39 ubiquitination and subsequent proteasomal degradation. Tasisulam exerts selective toxicity in parental HCT116 cancer cultures (IC50 = 6.5 μM), but not those harboring non-CUL4-DCAF15-associating RBM39 G268V mutant even at a high concentration of 50 μM.