Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Blood vessel sprouting and lumen formation. As vessels initiate sprouting, a cell (pink) adopts a tip cell phenotype, and through signaling of the Notch ligand Dll4 to neighboring cells sets up the stalk cell phenotype (blue), which is accompanied by up-regulation of Flt-1. As the sprout extends, the lumen forms behind the tip cell. sFlt-1, soluble Flt-1; mFlt-1, membrane Flt-1.
