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Disulfide Bonds In the Catalytic Domain Of Furin Are Necessary for Compartment‐Specific Folding Events
Author(s) -
Sucic Joe,
Lynd Jeremy,
Sucic Holly
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb66-a
Subject(s) - furin , endoplasmic reticulum , golgi apparatus , mutant , protein precursor , chemistry , microbiology and biotechnology , biochemistry , protein folding , biology , enzyme , gene
Disulfide bonds in the catalytic domain of furin are necessary for compartment‐specific folding events Furin is a subtilisin‐like endoprotease involved in processing a diverse array of proproteins within the secretory pathway of eucaryotes. Two disulfide bonds have been shown to form in the catalytic domain of furin (C104—C253 and C196—C226). We utilized site‐directed mutagenesis to change each cysteine residue to a serine. Consequences of the changes for furin activity were examined by coexpressing the mutant versions of furin with pro‐von Willebrand's factor (pro‐vWF), which is efficiently processed by wild type furin. These mutations completely abolished pro‐vWF processing ability. Trafficking and autocatalytic propeptide excision of the mutant furin proteins were also examined. The C196S and C226S mutants localized to the endoplasmic reticulum and exhibited no evidence of autocatalytic propeptide excision. The C104S and C253S mutants localized to a post‐endoplasmic reticulum compartment, with at least some of each mutant protein moving into the Golgi apparatus. Interestingly, these mutant versions of furin showed evidence of autocatlytic propeptide excision, but only after transit to the Golgi apparatus, in contrast to the generally accepted model for furin trafficking. The localization and activity of mutant versions of furin suggest that the disulfide bonds are necessary for compartment‐specific folding events proposed to occur as furin transits through the early compartments of the secretory pathway. Funded by the University of Michigan—Flint and the Horace H. Rackham School of Graduate Studies (University of Michigan, Ann Arbor, MI).