Platelet-derived endothelial cell growth factor.

Platelet-derived endothelial cell growth factor (PD-ECGF) is a 45 kDa single chain polypeptide which stimulates endothelial cell growth and chemotaxis in vitro and angiogenesis in vivo. Analysis of a full length PD-ECGF cDNA revealed an open reading frame coding for 482 amino acids without homology to other known proteins. No signal sequence was observed, and analysis of the biosynthesis and processing of PD-ECGF in a thyroid carcinoma cell line revealed that PD-ECGF is released only very slowly. PD-ECGF becomes covalently associated with nucleotide triphosphates (e.g., ATP) in vivo, as well as in vitro. The physiological significance of this posttranslational modification remains to be elucidated. The tissue distribution and target cell specificity of PD-ECGF suggest roles in angiogenesis (e.g., during wound healing and in the developing placenta), as well as in the maintenance of the integrity of the endothelial cell lining of large vessels.