Structure of two different Drosophila PsGEF (DmPsGEF) mRNAs and proteins and comparison of C2, PDZ, and RhoGEF domains of 5 PsGEFs from different species. (A) Exon-intron organization and splicing pattern of DmPsGEF. The rectangles with numbers represent the exons, and the straight lines between the exons represent the introns. Polyadenylation at the 3' ends of exon 4 and exon 7 results in the synthesis of short and long DmPsGEF mRNAs, respectively. (B) Domain organizations of DmPsGEF proteins. DmPsGEF short protein with 786 amino acids contains the C2 (red oval) and PDZ (green rectangle) domains, and DmPsGEF long protein with 1493 amino acids also contains the RhoGEF domain in addition (blue hexagon). (C) Comparison of C2, PDZ, and RhoGEF domains of DmPsGEF, TcPsGEF (Tribolium PsGEF), PhcPsGEF (Pediculus PsGEF), AmPsGEF (Apis PsGEF), and LgPsGEF (Lottia PsGEF). The amino acid sequences containing the C2, PDZ, and RhoGEF domains of TcPsGEF (amino acid 601 to 1313), PhcPsGEF (amino acid 14 to 700), AmPsGEF (amino acid 595–1238), and LgPsGEF (amino acid 18 to 730) proteins are compared with those of DmPsGEF (amino acid 272 to 1132). The numbers above C2, PDZ, and RhoGEF domains of TcPsGEF, PhcPsGEF, AmPsGEF, and LgPsGEF proteins represent % identity/% similarity of their amino acid sequences to those of DmPsGEF. See also Additional file 1 for the full-length amino acid sequences of five PsGEF proteins and Additional file 2 for alignment of above amino acid sequences.