Figure 4

Sequence alignment of human IPS-1 CARD domain with human MDA5 and human RIG-I CARD domains. The experimentally determined helices of IPS-1 CARD, and the predicted helical regions of the other CARDs are highlighted in green. Conserved hydrophobic core residues are indicated by *, and totally conserved residues by #. The blue and red triangles indicate the positive and negative residues, respectively, that are conserved across all species for the respective CARD domain. Lysines of RIG-I that can be ubiquitinated by TRIM25 E3 ubiquitin ligase are labelled 'Ub'. Below are three orthogonal views of homology models of the first CARD domains of MDA5 and RIG-I, colored by electrostatic surface potential. The views are equivalent for those shown for IPS-1 CARD in Figure 1.