Fig. 1.

Structural sequences of prokineticins and their non-mammalian counterparts. Prokineticins are two secreted human proteins that contain about 80 amino acids, with characteristic signal peptide sequence and 10 cysteine residues. The diagram displays the amino acid sequences of prokineticin 1 (A), prokineticin 2 (B), frog Bv8 (C), and partial sequence of mamba intestinal toxin 1 (D). Signal peptides are underlined. Ten conservative cysteine residues are marked (*). Arrows indicate the splice sites for introns. (Figure adapted from Li et al. [20]).