Biotechnology Letters, Vol.31, No.11, 1775-1782, 2009
Stress responses to heterologous membrane protein expression in Escherichia coli
The stress response of E. coli to the expression of two recombinant membrane proteins, the E. coli AAA+ protease FtsH and the human G-protein coupled receptor CB1, was examined using several members of a promoter-GFP library. Several genes from the heat-shock and envelope stress regulons (rpoH, clpP, lon, and ftsH) were strongly induced by expression of either membrane protein. Flow cytometry was used to monitor the real-time dynamics of the transcription of these reporter genes in response to membrane protein expression. Co-expression of CB1 and FtsH led to an additive response in these four reporter genes suggesting that the stresses may be occurring via different physiological mechanisms.