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 angiogenesis 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 propeptides. 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 approximately 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.

Vegfd modulates both angiogenesis and lymphangiogenesis during zebrafish embryonic development

“…Further to these binding studies, we also show that full-length zebrafish Vegfd is processed by proteolytic cleavage of the N-and C-terminal propeptides to generate the mature Vegfd peptide. This resembles the processing of mammalian/human VEGFD, via the proprotein convertases furin, PC5 and PC7 (McColl et al, 2003(McColl et al, , 2007, and the processing of zebrafish Vegfc, which likely requires the proprotein convertases furin, PC5 and PC7 (Khatib et al, 2010), similar to requirements in mammalian systems (Joukov et al, 1996;Siegfried et al, 2003). Activation of VEGFC requires CCBE1 and ADAMSTS3, but VEGFD is not processed in a CCBE1-dependent manner in these mammalian models (Bui et al, 2016;Jeltsch et al, 2014).…”

Proprotein Convertase Subtilisin/Kexin Type 7 (PCSK7) Is Essential for the Zebrafish Development and Bioavailability of Transforming Growth Factor β1a (TGFβ1a)

“…opmental Lethality-Previous in vitro experimental data show that FURIN can often replace PCSK7 (19,36,37). To compare and contrast how these enzymes regulate zebrafish development, we first interfered with furinA and furinB translation using morpholino technology.…”

Vascular endothelial growth factor-dependent and -independent regulation of angiogenesis

“…VEGF-C and VEGF-D are originally synthesized in premature forms, and processed by digestion with furin and other proprotein convertases to shortest forms (16). After processing, they acquire a strong ability to bind VEGFR3, and induce lymphangiogenesis.…”