Post-Translational Inhibition of IP-10 Secretion in IEC by Probiotic Bacteria: Impact on Chronic Inflammation

Peer reviewedPublisher PD

The death enzyme CP14 is a unique papain-like cysteine proteinase with a pronounced S2 subsite selectivity

The cysteine protease CP14 has been identified as a central component of a molecular module regulating programmed cell death in plant embryos. CP14 belongs to a distinct subfamily of papain-like cysteine proteinases of which no representative has been characterized thoroughly to date. However, it has been proposed that CP14 is a cathepsin H-like protease. We have now produced recombinant Nicotiana benthamiana CP14 (NbCP14) lacking the C-terminal granulin domain. As typical for papain-like cysteine proteinases, NbCP14 undergoes rapid autocatalytic activation when incubated at low pH. The mature protease is capable of hydrolysing several synthetic endopeptidase substrates, but cathepsin H-like aminopeptidase activity could not be detected. NbCP14 displays a strong preference for aliphatic over aromatic amino acids in the specificity-determining P2 position. This subsite selectivity was also observed upon digestion of proteome-derived peptide libraries. Notably, the specificity profile of NbCP14 differs from that of aleurain-like protease, the N. benthamiana orthologue of cathepsin H. We conclude that CP14 is a papain-like cysteine proteinase with unusual enzymatic properties which may prove of central importance for the execution of programmed cell death during plant development

The death enzyme CP14 is a unique papain-like cysteine proteinase with a pronounced S2 subsite selectivity

The cysteine protease CP14 has been identified as a central component of a molecular module regulating programmed cell death in plant embryos. CP14 belongs to a distinct subfamily of papain-like cysteine proteinases of which no representative has been characterized thoroughly to date. However, it has been proposed that CP14 is a cathepsin H-like protease. We have now produced recombinant Nicotiana benthamiana CP14 (NbCP14) lacking the C-terminal granulin domain. As typical for papain-like cysteine proteinases, NbCP14 undergoes rapid autocatalytic activation when incubated at low pH. The mature protease is capable of hydrolysing several synthetic endopeptidase substrates, but cathepsin H-like aminopeptidase activity could not be detected. NbCP14 displays a strong preference for aliphatic over aromatic amino acids in the specificity-determining P2 position. This subsite selectivity was also observed upon digestion of proteome-derived peptide libraries. Notably, the specificity profile of NbCP14 differs from that of aleurain-like protease, the N. benthamiana orthologue of cathepsin H. We conclude that CP14 is a papain-like cysteine proteinase with unusual enzymatic properties which may prove of central importance for the execution of programmed cell death during plant development

Plant-based strategies aimed at expressing HIV antigens and neutralizing antibodies at high levels. Nef as a case study

The first evidence that plants represent a valid, safe and cost-effective alternative to traditional expression systems for large-scale production of antigens and antibodies was described more than 10 years ago. Since then, considerable improvements have been made to increase the yield of plant-produced proteins. These include the use of signal sequences to target proteins to different cellular compartments, plastid transformation to achieve high transgene dosage, codon usage optimization to boost gene expression, and protein fusions to improve recombinant protein stability and accumulation. Thus, several HIV/SIV antigens and neutralizing anti-HIV antibodies have recently been successfully expressed in plants by stable nuclear or plastid transformation, and by transient expression systems based on plant virus vectors or Agrobacterium-mediated infection. The current article gives an overview of plant expressed HIV antigens and antibodies and provides an account of the use of different strategies aimed at increasing the expression of the accessory multifunctional HIV-1 Nef protein in transgenic plants

The use of plants for the production of therapeutic human peptides

Peptides have unique properties that make them useful drug candidates for diverse indications, including allergy, infectious disease and cancer. Some peptides are intrinsically bioactive, while others can be used to induce precise immune responses by defining a minimal immunogenic region. The limitations of peptides, such as metabolic instability, short half-life and low immunogenicity, can be addressed by strategies such as multimerization or fusion to carriers, to improve their pharmacological properties. The remaining major drawback is the cost of production using conventional chemical synthesis, which is also difficult to scale-up. Over the last 15 years, plants have been shown to produce bioactive and immunogenic peptides economically and with the potential for large-scale synthesis. The production of peptides in plants is usually achieved by the genetic fusion of the corresponding nucleotide sequence to that of a carrier protein, followed by stable nuclear or plastid transformation or transient expression using bacterial or viral vectors. Chimeric plant viruses or virus-like particles can also be used to display peptide antigens, allowing the production of polyvalent vaccine candidates. Here we review progress in the field of plant-derived peptides over the last 5 years, addressing new challenges for diverse pathologies