Amino acid alignment of GPA33 and the A34 protein (GPA34). The two proteins share 32% amino acid identity. In the GPA34 sequence, the signal peptide of A34 is boxed, the V_H-type Ig-like domain is underlined (solid), the C₂-type Ig-like domain is underlined (dashed), and the transmembrane domain is double underlined. Amino acid identities are shown below the alignments: *, identity; +, similarity.