Structure, sequence, and alignment of ARC with related proteins. (A) Schematic structure of human ARC. CARD and proline/glutamic acid-rich domains are shown as closed and open boxes. (B) The amino acid sequences of human and rat ARC are aligned. The identical residues in human and rat ARC were indicated by asterisk. (C) Alignment of the amino acid sequences of CARD domains of ARC, caspase-9, human caspase-2, RAIDD, and Apaf-1. The conserved residues in human and rat ARC were indicated by asterisk.