The structure of the caspase recruitment domain of BinCARD reveals that all three cysteines can be oxidized

Abstract

The caspase recruitment domain (CARD) is present in death-domain superfamily proteins involved in inflammation and apoptosis. BinCARD is named for its ability to interact with Bcl10 and inhibit downstream signalling. Human BinCARD is expressed as two isoforms that encode the same N-terminal CARD region but which differ considerably in their C-termini. Both isoforms are expressed in immune cells, although BinCARD-2 is much more highly expressed. Crystals of the CARD fold common to both had low symmetry (space group P1). Molecular replacement was unsuccessful in this low-symmetry space group and, as the construct contains no methionines, first one and then two residues were engineered to methionine for MAD phasing. The double-methionine variant was produced as a selenomethionine derivative, which was crystallized and the structure was solved using data measured at two wavelengths. The crystal structures of the native and selenomethionine double mutant were refined to high resolution (1.58 and 1.40 Å resolution, respectively), revealing the presence of a cis-peptide bond between Tyr39 and Pro40. Unexpectedly, the native crystal structure revealed that all three cysteines were oxidized. The mitochondrial localization of BinCARD-2 and the susceptibility of its CARD region to redox modification points to the intriguing possibility of a redox-regulatory role.

Structure-based alignment of human caspase recruitment domains provides a framework for understanding their function

“…This identified 14 specific sites, all of which contained hydrophobic residues in each of the structures, and which we have labelled h1 to h14 (Figure 1B and C). Eleven of these residues are consistent with an earlier comparison of 11 different CARD structures, with residues h3, h8 and h13 representing an expansion to the defining hydrophobic of the CARD (Chen et al, 2013). Almost all of these conserved positions are positioned on the inside of amphipathic helices, however, residues h3 and h7 are part of the H1-H2 and H2-H3 loops respectively.…”

Inflammasome Priming Mediated via Toll-Like Receptors 2 and 4, Induces Th1-Like Regulatory T Cells in De Novo Autoimmune Hepatitis

“…There were 135 genes significantly overexpressed in the clusters 3 + 4 vs. cluster 6 comparison and 258 genes significantly overexpressed in the cluster 6 vs. clusters 3 + 4 comparison (Figure S4C in Supplementary Material). Some of the significantly expressed genes in clusters 3 + 4 cells (i.e., DAIH monocytes/macrophages) compared to cluster 6 cells (i.e., LTC monocytes/macrophages) include HMGB1 , which provides inflammatory signal 1 to TLR 4 in the two-signal activation of the inflammasome machinery ( 3 ), CARD19 , the caspase recruitment domain (CARD) is present in death-domain superfamily proteins and involved in inflammation and apoptosis ( 7 ). Importantly, the inflammasome complex includes a CARD containing protein ( 8 ), and TIMP1 (Figure 4 B).…”

CARD19, the protein formerly known as BinCARD, is a mitochondrial protein that does not regulate Bcl10-dependent NF-κB activation after TCR engagement

“…A 2013 paper identified BinCARD-2, described as a second BinCARD isoform that was transcribed at significantly higher levels than BinCARD-1 (the protein product of AK057716) [12]. Ectopically expressed BinCARD-2 was shown to localize to the endoplasmic reticulum and the mitochondria in HEK293T cells [12].…”