title: T cell antigen receptor stimulation induces MALT1 paracaspase-mediated cleavage of the NF-kappaB inhibitor A20.
abstract: The paracaspase MALT1 mediates T cell antigen receptor-induced signaling to the transcription factor NF-kappaB and is indispensable for T cell activation and proliferation. Enhanced expression of MALT1 or aberrant expression of a fusion protein of the apoptosis inhibitor API2 and MALT1 has been linked to mucosa-associated lymphoid tissue lymphoma. Despite the presence of a caspase-like domain, MALT1 proteolytic activity has not yet been demonstrated. Here we show that T cell antigen receptor stimulation induced recruitment of the NF-kappaB inhibitor A20 into a complex of MALT1 and the adaptor protein Bcl-10, leading to MALT1-mediated processing of A20. API2-MALT1 expression likewise resulted in cleavage of A20. MALT1 cleaved human A20 after arginine 439 and impaired its NF-kappaB-inhibitory function. Our studies identify A20 as a substrate of MALT1 and emphasize the importance of MALT1 proteolytic activity in the 'fine tuning' of T cell antigen receptor signaling.
authors.affiliation: Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Coornaert
authors.forename: Mathijs
authors.initials: M
authors.lastname: Baens
authors.forename: Karen
authors.initials: K
authors.lastname: Heyninck
authors.forename: Tine
authors.initials: T
authors.lastname: Bekaert
authors.forename: Mira
authors.initials: M
authors.lastname: Haegman
authors.forename: Jens
authors.initials: J
authors.lastname: Staal
authors.forename: Lijun
authors.initials: L
authors.lastname: Sun
authors.forename: Zhijian J
authors.initials: ZJ
authors.lastname: Chen
authors.forename: Peter
authors.initials: P
authors.lastname: Marynen
authors.forename: Rudi
authors.initials: R
authors.lastname: Beyaert
mesh_terms: D020169:Caspases / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D004268:DNA-Binding Proteins; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000276:immunology; D000074884:Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D009363:Neoplasm Proteins / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D014162:Transfection; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3
chemical_list: D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011948:Receptors, Antigen, T-Cell; D010447:Peptide Hydrolases; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D020169:Caspases; C400109:MALT1 protein, human; D000074884:Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein