MALT1 Gene

The MALT1 gene (MALT1 stands for: Mucosa-Associated Lymphoid Tissue Lymphoma Translocation Protein 1) is a protein-coding gene located on chromosome 18q21.32.

The MALT1 gene encodes a caspase-like protease that plays a role in BCL10-induced activation of NF-kappaB. The protein is a component of the "CARMA1-BCL10-MALT1 (CBM) signalosome" that triggers NF-kappaB signaling and lymphocyte activation after stimulation by antigen receptors (Ma Y et al. 2014).

Caspase-like protease encoded by the MALT1 gene, enhances BCL10-induced activation. The protease acts via the formation of CBM complexes, via adaptive and innate immune signaling downstream of the CARD domain-containing proteins (CARD9, CARD11, and CARD14). Furthermore, it stimulates the expression of genes encoding proinflammatory cytokines and chemokines. The MALT1 protease mediates the cleavage of BCL10. This enzymatic BCL10 cleavage plays an important role in T cell antigen receptor-induced integrin adhesion. Furthermore, the enzyme is involved in the induction of T helper 17 (Th17) cell differentiation. It cleaves RC3H1 and ZC3H12A in response to T cell receptor (TCR) stimulation, releasing their cooperatively suppressed targets to promote Th17 cell differentiation. It may also possess ubiquitin ligase activity: binds to TRAF6, induces TRAF6 oligomerization and activation of its ligase activity (Afonina IS et al. 2015).

The MALT1 gene is frequently rearranged in chromosomal translocations with other genes in mucosa-associated lymphoid tissue lymphomas (MALT lymphomas). Thus, in a t(11;18)(q21; q21) translocation with the baculoviral IAP repeat-containing protein 3 (also known as apoptosis inhibitor 2) locus [BIRC3(API2)-MALT1]. Furthermore, in a t(14;18)(q32;q21) translocation with the immunoglobulin heavy chain locus (IGH-MALT1).

Diseases associated with MALT1 include:

• Immunodeficiency 12 /OMIM: 615468/ (Jabara HH et al. 2013; McKinnon ML et al. 2014).
• MALT-type marginal zone B-cell lymphoma (MALT lymphoma; see also SALT lymphoma).

1. Afonina IS et al (2015) MALT1--a universal soldier: multiple strategies to ensure NF-κB activation and target gene expression. FEBS J 282:3286-3297.
2. Jabara HH et al (2013) A homozygous mucosa-associated lymphoid tissue 1 (MALT1) mutation in a family with combined immunodeficiency. J. Allergy Clin. Immun. 132: 151-158, 2013. note: erratum: J Allergy Clin Immun 132: 773.
3. Ma Y et al (2014) Characteristics of CARMA1-BCL10-MALT1-A20-NF-κB expression in T cell-acute lymphocytic leukemia. Eur J Med Res 19:62.
4. McKinnon ML et al (2014) Combined immunodeficiency associated with homozygous MALT1 mutations. (Letter) J Allergy Clin Immun 133: 1458-1462.