Skip to main content
. Author manuscript; available in PMC: 2009 Dec 7.
Published in final edited form as: Mol Reprod Dev. 2009 Dec;76(12):1116–1127. doi: 10.1002/mrd.21066

Figure 1.

Figure 1

HBEGF processing and signaling. In its transmembrane form, proHBEGF is proteolytically cleaved by metalloproteinases at the cell surface to remove (scissors) its pro-domain and secrete the extracellular domain (sHBEGF shedding). sHBEGF is then free to diffuse to nearby receptor tyrosine kinases where it can bind either HER1 (EGF receptor) or HER4. Receptor binding requires heparin sulfate proteoglycan (HSPG) as cofactor, and induces HER homo- or heterodimerization. Receptor autophosphorylation initiates down-stream intracellular signaling. Heparin sulfate proteoglycan (HSPG); human epidermal growth factor receptor family member (HER); matrix metalloproteinase (MMP); a disintegrin and metalloproteinase (ADAM).