Substrate Cleavage Analysis of Furin and Related Proprotein Convertases

A COMPARATIVE STUDY*

  1. Alex Y. Strongin,2
  1. Burnham Institute for Medical Research, La Jolla, California 92037, §Illumina, Inc., San Diego, California 92121, and University of Sherbrooke, Sherbrooke, Quebec J1H SN4, Canada
  1. 2 To whom correspondence should be addressed: Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037. Tel.: 858-713-6271; E-mail: strongin{at}burnham.org.

Abstract

We present the data and the technology, a combination of which allows us to determine the identity of proprotein convertases (PCs) related to the processing of specific protein targets including viral and bacterial pathogens. Our results, which support and extend the data of other laboratories, are required for the design of effective inhibitors of PCs because, in general, an inhibitor design starts with a specific substrate. Seven proteinases of the human PC family cleave the multibasic motifs R-X-(R/K/X)-R↓ and, as a result, transform proproteins, including those from pathogens, into biologically active proteins and peptides. The precise cleavage preferences of PCs have not been known in sufficient detail; hence we were unable to determine the relative importance of the individual PCs in infectious diseases, thus making the design of specific inhibitors exceedingly difficult. To determine the cleavage preferences of PCs in more detail, we evaluated the relative efficiency of furin, PC2, PC4, PC5/6, PC7, and PACE4 in cleaving over 100 decapeptide sequences representing the R-X-(R/K/X)-R↓ motifs of human, bacterial, and viral proteins. Our computer analysis of the data and the follow-on cleavage analysis of the selected full-length proteins corroborated our initial results thus allowing us to determine the cleavage preferences of the PCs and to suggest which PCs are promising drug targets in infectious diseases. Our results also suggest that pathogens, including anthrax PA83 and the avian influenza A H5N1 (bird flu) hemagglutinin precursor, evolved to be as sensitive to PC proteolysis as the most sensitive normal human proteins.

Footnotes

  • * This work was supported, in whole or in part, by National Institutes of Health Grants AI061139 (to A. Y. S.), RR020843 (to J. W. S. and A. Y. S.), and AI055789 (to R. C. L. and A. Y. S.). This work was also supported by CIHR Grants (to R. Day). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

  • Graphic The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1 and S2 and Table S1.

  • 1 Current address: Dept. of Life Sciences, Division of Life and Pharmaceutical Sciences and the Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea.

  • Received May 16, 2008.
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