EC morphogenesis on Matrigel is modulated by GAS6. (A) Morphologic aspect of ECs plated on Matrigel for 12 hours in the presence of M199 containing 0.5% FCS (i) supplemented with GAS6 (100 ng/mL) (ii), GAS6 in the presence of Axl-Ig (1 μg/mL) (iii), or Axl-Ig alone (iv). Pictures are representative of 5 independent experiments. Images were processed by Image Proplus 4.0 (Media Cybernetycs, Leiden, The Netherlands). (B) Dose-dependent inhibition of EC morphogenesis by GAS6. Tubular structures were quantified by automatic counting of tube formation after 12 hours. Percentage of inhibition was expressed using untreated GAS6 cells as 100%. Mean ± SD of 4 experiments.