Fig. 2. Chromosomal translocations in MALT lymphoma. Shown are the products of two recurrent chromosomal translocations seen in MALT B-cell lymphomas. Overexpression of either wild-type Bcl10 or the API2-MALT1 fusion protein is thought to result in excessive NF-B activation, although Bcl10 might require an intact downstream factor, MALT1. In both cases, oligomerization-dependent activation of the MALT1 protease (caspase-like) domain appears to play an important role for the subsequent stimulation of the IKK complex.