Figure 7.

Epidermal growth factor-like domain 7 (EGFL7) interacts with and activates epidermal growth factor receptor (EGFR) in Jeg3 cells. (A) Alignment of the amino acid (aa) sequences of EGFL7 and epidermal growth factor (EGF). The signal peptide of EGFL7 is marked with a green line (aa 1–23), the EMI domain with an orange line (aa 27–104), the EGF-like domain with a red line (aa 103–135), the Ca²⁺ EGF-like domain with a blue line (aa 137–177). Amino acids involved in EGFR binding that are conserved between EGF and EGFL7 are depicted by rectangles. Amino acids that are involved in EGFR binding but are not conserved between EGF and EGFL7 are underlined (Van Zoelen et al., 2000). Asterisks = positions which have a single, fully conserved residue; colons = conservation between groups of strongly similar properties; periods = conservation between groups of weakly similar properties. Legend for the colors: Red = AVFPMILW, small, hydrophobic; Blue = DE, acidic; Magenta = RK, basic; Green = STYHCNGQ, hydroxyl, sulfhydryl, amine; Grey = others, unusual aa. (B) Western blot analysis of pEGFR in JegGFP (control) and JegE7 (overexpressing EGFL7), with densitometric analysis (C). (D) Double immunofluorescent staining of JegGFP and JegE7 cells for EGFL7 (green), EGFR (red), and Hoechst (blue). Arrows indicate co-localization of EGFL7 and EGFR. *P < 0.05. Scale bars = 50 µm.