Mechanism and specificity of the human paracaspase MALT1.

Abstract

The paracaspase domain of MALT1 (mucosa-associated lymphoid tissue lymphoma translocation protein 1) is a component of a gene translocation fused to the N-terminal domains of the cellular inhibitor of apoptosis protein 2. The paracaspase itself, commonly known as MALT1, participates in the NF-κB (nuclear factor κB) pathway, probably by driving survival signals downstream of the B-cell antigen receptor through MALT1 proteolytic activity. We have developed methods for the expression and purification of recombinant full-length MALT1 and its constituent catalytic domain alone. Both are activated by dimerization without cleavage, with a similar dimerization barrier to the distantly related cousins, the apical caspases. By using positional-scanning peptidyl substrate libraries we demonstrate that the activity and specificity of full-length MALT1 is recapitulated by the catalytic domain alone, showing a stringent requirement for cleaving after arginine, and with striking peptide length constraints for efficient hydrolysis. Rates of cleavage (kcat/Km values) of optimal peptidyl substrates are in the same order (10(3)-10(4) M(-1)·s(-1)) as for a putative target protein CYLD. Thus MALT1 has many similarities to caspase 8, even cleaving the putative target protein CYLD with comparable efficiencies, but with diametrically opposite primary substrate specificity.

• Authors: Janna Hachmann, Scott J Snipas, Bram J van Raam, Erik M Cancino, Emily J Houlihan, Marcin Poreba, Paulina Kasperkiewicz, Marcin Drag, Guy S Salvesen
• Journal: The Biochemical journal (Biochem J) Vol. 443 Issue 1 Pg. 287-95 (Apr 01 2012) ISSN: 1470-8728 [Electronic] England
• PMID: 22309193 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Citrates
• Enzyme Activators
• Neoplasm Proteins
• Oligopeptides
• Recombinant Fusion Proteins
• Sodium Citrate
• Caspases
• MALT1 protein, human
• Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein

Topics

• Amino Acid Sequence
• Caspases (biosynthesis, chemistry, isolation & purification)
• Chromatography, Affinity
• Citrates (chemistry)
• Enzyme Activation
• Enzyme Activators (chemistry)
• Escherichia coli
• HEK293 Cells
• Humans
• Kinetics
• Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein
• Neoplasm Proteins (biosynthesis, chemistry, isolation & purification)
• Oligopeptides (chemistry)
• Protein Stability
• Protein Structure, Tertiary
• Proteolysis
• Recombinant Fusion Proteins (biosynthesis, chemistry, isolation & purification)
• Sodium Citrate
• Substrate Specificity