Sequence comparison of Imp-L2, its invertebrate homologs, and IGFBP-rP1. The sequences of Imp-L2 (Drosophila), Insulin-related peptide binding protein (IBP; S. frugiperda), ZIG-4 (C. elegans) and IGFBP-rP1 (human) were aligned using ClustalW2 . Residues identical or similar in at least three sequences are highlighted in black and gray, respectively. Asterisks below the sequence show the cysteines thought to form two disulfide bridges. The two immunoglobulin-like domains are indicated by a gray bar and the region in IGFBP-rP1 that has the most similarity to IGFBPs by a black bar below the sequences. The annotation was adapted from [2, 9].