Co-expression of the protease furin in Nicotiana benthamiana leads to efficient processing of latent transforming growth factor-?1 into a biologically active protein.

ABSTRACT: Transforming growth factor beta (TGF-?) is a signalling molecule that plays a key role in developmental and immunological processes in mammals. Three TGF-? 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-?3 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-?1 in Nicotiana benthamiana plants. We successfully expressed mature TGF-?1 in the absence of the latency-associated peptide (LAP) using different strategies, but the obtained proteins were inactive. Upon expression of LAP-TGF-?1, 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-?1, and co-expression of human furin enabled the proteolytic processing of latent TGF-?1. Engineering the plant post-translational machinery by co-expressing human furin also enhanced the accumulation of biologically active TGF-?1. 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.

SUBMITTER: Wilbers RH 

PROVIDER: S-EPMC5067602 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature