F-Spondin/SPON1 Proteins and Enzymes

F-Spondin is a secreted protein expressed at high levels in the embryonic floor plate. The ECM-attached protein plays a dual role in patterning the nervous system; it promotes outgrowth of commissural axons and inhibits outgrowth of motor axons. F-Spondin contains six thrombospondin repeats which interact with the apolipoprotein E receptor.