Proprotein convertases promote processing of VEGF‐D, a critical step for binding the angiogenic receptor VEGFR‐2

ABSTRACT Vascular endothelial growth factor (VEGF)‐D is a secreted glycoprotein that induces angio‐genesis and lymphangiogenesis. It consists of a central domain, containing binding sites for VEGF receptor‐2 (VEGFR‐2) and VEGFR‐3, and N‐ and C‐terminal propep‐tides. It is secreted from the cell as homodimers of the full‐length form that can be proteolytically processed to remove the propeptides. It was recently shown, using adenoviral gene delivery, that fully processed VEGF‐D induces angiogenesis in vivo , whereas full‐length VEGF‐D does not. To better understand these observations, we monitored the effect of VEGF‐D processing on receptor binding using a full‐length VEGF‐D mutant that cannot be processed. This mutant binds VEGFR‐2, the receptor signaling for angiogenesis, with ~17, 000‐fold lower affinity than mature VEGF‐D, indicating the importance of processing for interaction with this receptor. Further, we show that members of the proprotein convertase (PC) family of proteases promote VEGF‐D processing, which facilitates the VEGF‐D/VEGFR‐2 interaction. The PCs furin and PC5 promote cleavage of both propeptides, whereas PC7 promotes cleavage of the C‐terminal propeptide only. The finding that PCs promote activation of VEGF‐D and other proteins with roles in cancer such as matrix metalloproteinases, emphasizes the importance of these enzymes as potential regulators of tumor progression and metastasis.—McColl, B. K., Paavonen, K., Karnezis, T., Harris, N. C., Davydova, N., Rothacker, J., Nice, E. C., Harder, K. W., Roufail, S., Hibbs, M. L., Rogers, P. A. W., Alitalo, K., Stacker, S. A., Achen, M. G. Proprotein convertases promote processing of VEGF‐D, a critical step for binding the angiogenic receptor VEGFR‐2. FASEB J. 21, 1088–1098 (2007)