Proprotein Convertase Processing Enhances Peroxidasin Activity to Reinforce Collagen IV.

Colon S, Bhave G
J Biol Chem. 2016 291 (46): 24009-24016

PMID: 27697841 · PMCID: PMC5104926 · DOI:10.1074/jbc.M116.745935

The basement membrane (BM) is a form of extracellular matrix that underlies cell layers in nearly all animal tissues. Type IV collagen, a major constituent of BMs, is critical for tissue development and architecture. The enzyme peroxidasin (Pxdn), an extracellular matrix-associated protein, catalyzes the formation of structurally reinforcing sulfilimine cross-links within the collagen IV network, an event essential to basement membrane integrity. Although the catalytic function of Pxdn is known, the regulation of its activity remains unclear. In this work we show through N-terminal sequencing, pharmacologic studies, and mutational analysis that proprotein convertases (PCs) proteolytically process human Pxdn at Arg-1336, a location relatively close to its C terminus. PC processing enhances the enzymatic activity of Pxdn and facilitates the formation of sulfilimine cross-links in collagen IV. Thus, PC processing of Pxdn is a key regulatory step that contributes to its function and, therefore, supports BM integrity and homeostasis.

© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

MeSH Terms (8)

Basement Membrane Collagen Type IV Extracellular Matrix Proteins HEK293 Cells Humans Peroxidase Proprotein Convertases Protein Domains

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