Plant biotech & Risk Assessment
Benchabane, Meriem , Gomord, Véronique , Saint-Jore Dupas, Claude , Faye, Loïc , Michaud, Dominique .
Unexpected post-translational maturation of a human serpin, alpha-1-antichymotrypsin, expressed in a plant cell-based biofactory.
Plants represent interesting production platforms for recombinant proteins of therapeutical value. While the proof of concept for protein production in plants is no longer a matter of debate, protein stability and post-translational modifications essential for biological activity pose, on the other hand, serious challenges to the development of plant factories. Plant cells can perform most protein post-translational modifications, but plant and mammalian proteins often present minor but significant differences, with a possible negative impact on their commercial value. To assess the potential of plants for the production of structurally-complex mammalian proteins, we expressed human alpha-1-antichymotrypsin (AACT), a glycosylated serine protease inhibitor, in culture BY2 tobacco cells. The inhibitor was targeted to different subcellular compartments to assess the impact of cellular final destination on accumulation, stability and glycosylation of the resulting variants. Pulse-chase experiments revealed that AACT entering the secretory pathway, initially detected as 50-kDa protein, was readily processed to lower molecular weight forms. This post-translational maturation apparently was the result of glycan maturation and proteolytic processing of the polypeptide along the secretory pathway. Sequestering AACT in the ER was inefficient to generate high levels of homogenous product, in contrast with previous studies reporting the usefulness of this approach to improve protein stability and avoid the addition of unwanted complex glycans. Taken together, these results illustrate the complex and unpredictable nature of recombinant protein post-translational maturation, and stress the need for additional empirical data on the expression of complex glycopropteins in plant cells.
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1 - CRH/INAF Université Laval, Département de Phytologie, Québec, Québec, G1K 7P4, Canada
2 - CNRS UMR 6037, Université de Rouen, Mont-Saint Aignan, 76821, France
recombinant protein production
protein post-translational modification
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM