Cell-penetrating peptides stimulate protein transport on the Twin-arginine translocation pathway: evidence for a membrane thinning and toroidal pore mechanism

Abstract

The Tat pathway is essential for photosynthetic protein transport across plant thylakoid membranes and is also ubiquitous throughout prokaryotes and archaea. The Tat pathway is quite unique amongst protein translocation pathways as it specializes in transporting folded proteins driven by a proton motive force. Mechanistic details of the actual translocation step (s) of the pathway remain elusive. Here, we show that membrane thinning stimulates Tat transport and, conversely, membrane strengthening abolishes Tat transport. We draw parallels from the Tat machinery to cell penetrating peptides and propose that the Tat pore could be toroidal, as in most pores formed by cell penetrating peptides.