The enamel knot produces a range of molecular signals from all the major signaling families, such as Fibroblast Growth Factors (FGF), Bone morphogenetic proteins (BMP), Hedgehog (Hh) and Wnt signals.
These molecular signals direct the growth of the surrounding epithelium and ectomesenchyme.
The primary enamel knot forms at the tip of the bud during the cap stage of tooth development.
This primary enamel knot undergoes apoptosis and disappears.
Later, secondary enamel knots appear that regulate the formation of the future cusps of the teeth.