tetramethylrhodamine and Lymphoma--Large-B-Cell--Diffuse

MALT1 paracaspase is activated upon antigen receptor stimulation to promote lymphocyte activation. In addition, deregulated MALT1 protease activity drives survival of distinct lymphomas such as the activated B cell type of diffuse large B cell lymphoma (ABC-DLBCL). Here, we designed fluorophore or biotin-coupled activity based-probes (ABP) that covalently modify the active center of MALT1. MALT1-ABPs are exclusively labeling an active modified full length form of MALT1 upon T cell stimulation. Further, despite the CARMA1 requirement for initial MALT1 activation, the MALT1-ABPs show that protease activity is not confined to the high-molecular CARMA1-BCL10-MALT1 (CBM) complex. Using biotin-coupled ABPs, we developed a robust assay for sensitive and selective detection of active MALT1 in cell lines, primary lymphocytes, and DLBCL tumor biopsies. Taken together, MALT1-ABPs represent powerful chemical tools to measure cellular MALT1 activation, determine efficacy of small molecule inhibitors, and classify lymphomas based on MALT1 activity status.

Topics: Biotin; Blotting, Western; CARD Signaling Adaptor Proteins; Caspases; Cell Line; Click Chemistry; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Guanylate Cyclase; Humans; Jurkat Cells; Lymphoma, Large B-Cell, Diffuse; Molecular Probes; Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein; Neoplasm Proteins; Rhodamines; RNA Interference; RNA, Small Interfering; T-Lymphocytes