title: Preventing unintended proteolysis in plant protein biofactories.
abstract: Numerous reports have been published over the last decade assessing the potential of plants as useful hosts for the heterologous expression of clinically useful proteins. Significant progress has been made, in particular, in optimizing transgene transcription and translation in plants, and in elucidating the complex post-translational modifications of proteins typical of the plant cell machinery. In this article, we address the important issue of recombinant protein degradation in plant expression platforms, which directly impacts on the final yield, homogeneity and overall quality of the resulting protein product. Unlike several more stable and structurally less complex pharmaceuticals, recombinant proteins present a natural tendency to structural heterogeneity, resulting in part from the inherent instability of polypeptide chains expressed in heterologous environments. Proteolytic processing, notably, may dramatically alter the structural integrity and overall accumulation of recombinant proteins in plant expression systems, both in planta during expression and ex planta after extraction. In this article, we describe the current strategies proposed to minimize protein hydrolysis in plant protein factories, including organ-specific transgene expression, organelle-specific protein targeting, the grafting of stabilizing protein domains to labile proteins, protein secretion in natural fluids and the co-expression of companion protease inhibitors.
authors.affiliation: Département de phytologie, CRH/INAF, Université Laval, QC, Canada.
authors.forename: Meriem
authors.initials: M
authors.lastname: Benchabane
authors.forename: Charles
authors.initials: C
authors.lastname: Goulet
authors.forename: Daniel
authors.initials: D
authors.lastname: Rivard
authors.forename: Loïc
authors.initials: L
authors.lastname: Faye
authors.forename: Véronique
authors.initials: V
authors.lastname: Gomord
authors.forename: Dominique
authors.initials: D
authors.lastname: Michaud
mesh_terms: D015870:Gene Expression; D006868:Hydrolysis; D010447:Peptide Hydrolases / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000378:metabolism*; D011480:Protease Inhibitors / Q000737:chemistry; D015202:Protein Engineering / Q000379:methods*; D021381:Protein Transport; D011994:Recombinant Proteins / Q000378:metabolism*; D019076:Transgenes
chemical_list: D010940:Plant Proteins; D011480:Protease Inhibitors; D011994:Recombinant Proteins; D010447:Peptide Hydrolases