1. Membrane protein overexpression affects the pH of the culture and protein secretion.A, the pH of the culture of GFP fusion-overexpressing cells and the control cells was measured every 4 h.
Membrane protein overexpression affects the pH of the culture and protein secretion.A, the pH of the culture of GFP fusion-overexpressing cells and the control cells was measured every 4 h. Membrane protein overexpression resulted in the slight acidification of the culture medium in contrast to overexpression of the soluble GST-GFP. B, cells overexpressing GFP fusion proteins were pulse-labeled with [35S]methionine, and subsequently OmpA was immunoprecipitated and analyzed as described under “Experimental Procedures.” Membrane protein overexpression led to OmpA precursor accumulation, whereas overexpression of the soluble protein GST-GFP did not.
Samuel Wagner et al. Mol Cell Proteomics 2007;6:
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