Figure 7: API2–MALT1 cleaves LIMA1α to promote B-cell lymphomagenesis in vivo. | Nature Communications

Figure 7: API2–MALT1 cleaves LIMA1α to promote B-cell lymphomagenesis in vivo.

From: Conversion of the LIMA1 tumour suppressor into an oncogenic LMO-like protein by API2–MALT1 in MALT lymphoma

Figure 7

(a) Cleavage of LIMA1α by API2–MALT1 and cleaved LMO fragment promotes B-cell lymphomagenesis in vivo. Injection of cells into SCID/BEIGE mice and tumour size measurement were performed as described in Fig. 6c. (i) Change in tumour volume in L428 cells transduced with recombinant lentiviruses bearing scrRNA, shLIMA1, LMO-like, AM, AM plus LIMA1αWt or LIMA1αR206AK289AMut. The data are presented as means±s.d. of n=5 experimental groups. (ii) Representative tumours in SCID/BEIGE mice (n=5). (b) Proteolytic cleavage fragments of LIMA1 are present in human MALT lymphomas with t(11;18)(q21;q21) chromosomal aberration, but not in BCLs without the t(11;18)(q21;q21). Evidence of the presence of t(11;18)(q21;q21) in MALT lymphomas was corroborated using a MALT1 break-apart DNA-FISH probe-based strategy (Abbott Molecular; see Supplementary Fig. 7c). Wild-type (full-length) endogenous LIMA1 and cleavage fragments were detected by western blot with rabbit anti-LIMA1 antibody. Equal quantities of cell lysates (15 μg) from L428 cells and human B cells and patient-derived lymphomas were used in all experiments. (c) Model of API2–MALT1-mediated LIMA1α cleavage and its contribution to B-cell MALT lymphoma pathogenesis.

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