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Updated: Jul 11, 2026

A Convenient and General Expression Platform for the Production of Secreted Proteins from Human Cells
Published on: July 31, 2012
Is Ffh required for export of secretory proteins?
1Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269-3044, USA.
Abstract:
In Escherichia coli, protein export from the cytoplasm may occur via the signal recognition particle (SRP)-dependent pathway or the Sec-dependent pathway. Membrane proteins utilize the SRP-dependent route, whereas many secretory proteins use the cytoplasmic Sec machinery. To examine the possibility that signal peptide hydrophobicity governs which targeting route is utilized, we used a series of PhoA signal sequence mutants which vary only by incremental hydrophobicity changes. We show that depletion of SRP, but not trigger factor, affects all the mutants examined. These results suggest secretory proteins with a variety of signal sequences, as well as membrane proteins, require SRP for export.
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