|Title||Co-expression of the protease furin in Nicotiana benthamiana leads to efficient processing of latent transforming growth factor-b1 into a biologically active protein|
|Author(s)||Wilbers, R.H.P.; Westerhof, L.B.; Raaij, D.R. van; Adrichem, Marloes van; Prakasa, A.D.; Lozano Torres, J.L.; Bakker, J.; Smant, G.; Schots, A.|
|Source||Plant Biotechnology Journal 14 (2016)8. - ISSN 1467-7644 - p. 1695 - 1704.|
Laboratory of Nematology
|Publication type||Refereed Article in a scientific journal|
|Abstract||Transforming growth factor beta (TGF-β) is a signalling molecule that plays a key role in developmental and immunological processes in mammals. Three TGF-β isoforms exist in humans, and each isoform has unique therapeutic potential. Plants offer a platform for the production of recombinant proteins, which is cheap and easy to scale up and has a low risk of contamination with human pathogens. TGF-β3 has been produced in plants before using a chloroplast expression system. However, this strategy requires chemical refolding to obtain a biologically active protein. In this study, we investigated the possibility to transiently express active human TGF-β1 in Nicotiana benthamiana plants. We successfully expressed mature TGF-β1 in the absence of the latency-associated peptide (LAP) using different strategies, but the obtained proteins were inactive. Upon expression of LAP-TGF-β1, we were able to show that processing of the latent complex by a furin-like protease does not occur in planta. The use of a chitinase signal peptide enhanced the expression and secretion of LAP-TGF-β1, and co-expression of human furin enabled the proteolytic processing of latent TGF-β1. Engineering the plant post-translational machinery by co-expressing human furin also enhanced the accumulation of biologically active TGF-β1. This engineering step is quite remarkable, as furin requires multiple processing steps and correct localization within the secretory pathway to become active. Our data demonstrate that plants can be a suitable platform for the production of complex proteins that rely on specific proteolytic processing.