The protease MALT1 promotes B-cell dependent immune responses and lymphoma dissemination by cleavage of the adaptor protein Tensin-3

In a recent publication in PNAS, Mélanie Juilland, Nagham Alouche and associates from the laboratories of Sanjiv Luther and Margot Thome-Miazza report that the protease MALT1 cleaves the adaptor protein Tensin-3 to regulate integrin-dependent B-cell adhesion and metastatic dissemination of B-cell lymphoma cells.  The researchers noticed that MALT1 efficiently cleaved Tensin-3 in activated B-cells, and that this cleavage enhanced humoral immune responses. In B-cell lymphoma cells with constitutive, oncogenic MALT1 activity, decreased cellular Tensin-3 levels favored metastatic spreading of lymphoma cells to the bone marrow and spleen.  These findings point to a unique, transcription-independent function for MALT1 in the regulation of B-cell adhesion, with implications for MALT1-dependent tumorigenesis.