MALT1 and diffuse large B-cell lymphoma: Subsequently, we found that the levels of GLS1 protein (Figure 5B) and intracellular glutamate (Figure 5C) were down-regulated in ABC-DLBCL cells without MALT1 protease activity but up-regulated in GCB-DLBCL cells with MALT1 protease activity (Supplementary Figures 3B,C).