Cross-system excision of chaperone-mediated proteolysis in chaperone-assisted recombinant protein production

Abstract

Main Escherichia coli cytosolic chaperones such as DnaK are key components

of the control quality network designed to minimize the prevalence of

polypeptides with aberrant conformations. This is achieved by both favouring

refolding activities but also stimulating proteolytic degradation of folding

reluctant species. This last activity is responsible for the decrease of the

proteolytic stability of recombinant proteins when co-produced along with DnaK,

where an increase in solubility might be associated to a decrease in protein

yield. However, when DnaK and its co-chaperone DnaJ are co-produced in

cultured insect cells or whole insect larvae (and expectedly, in other

heterologous hosts), only positive, folding-related effects of these chaperones

are observed, in absence of proteolysis-mediated reduction of recombinant

protein yield.

Acknowledgements

The authors appreciate the financial support through grants BIO2007-61194 and EUI2008-03610 (MICINN). We also acknowledge the support of the CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Spain. M.M.A. is recipient of a predoctoral fellowship from MEC, Spain. A.V. has been distinguished with an ICREA ACADEMIA award (Catalonia, Spain).

Figures and Tables

Figure 1 Model of DnaK and DnaJ differential action in bacterial and eukaryotic systems. By rehosting the chaperones to a system lacking orthologs of the bacterial proteases Lon and ClpP, proteolysis can be avoided while keeping the conserved foldase activity of the DnaK/J pair.

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