CASC3 and Miyoshi myopathy: Here, we examined the anti-MM effect of a novel syringolin compound named as syringolog-1 (Figure 1), which inhibits both CT-L and T-L activities in MM cells, and found that dual inhibition of the CT-L and T-L activities of the 20S proteasome was a potent treatment strategy for MM, including Btz-resistant cases.