Structure-based dendrogram of inferred relationships between Ig
domain-containing receptors. An all-against-all structural distance
matrix was determined using FcγRIIb domain (D)2 (PDB entry name
2FCBA), human KIR-D2 (1NKR), β2 μ-D1 (1BMG), Hemolin-D1 (1BIH),
TrkB-D1 (1WWB), CD2-D1 (1HNF), CD4-D1 (3CD4), CD8-D1 (1CD8), ICAM-D1
(1IAM), MadCAM-D1 (1BQS), and HTF-D1 (1BOY). The optimal tree topology
was estimated by parsimony analysis with global rearrangements. With
the exception of FcγRIIb and KIR, domain classifications are
indicated along branches according to the SCOP database. A fibronectin
type III (HTF) domain serves as an outgroup to root the tree.