Sec-dependent membrane protein insertion: sequential interaction of nascent FtsQ with SecY and YidC |
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Authors: | Malene L Urbanus Pier A Scotti Linda Frderberg Annika Sf Jan-Willem L de Gier Josef Brunner James C Samuelson Ross E Dalbey Bauke Oudega and Joen Luirink |
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Institution: | Malene L. Urbanus, Pier A. Scotti, Linda Fröderberg, Annika Sääf, Jan-Willem L. de Gier, Josef Brunner, James C. Samuelson, Ross E. Dalbey, Bauke Oudega, and Joen Luirink |
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Abstract: | Recent studies identified YidC as a novel membrane factor that may play a key role in membrane insertion of inner membrane proteins (IMPs), both in conjunction with the Sec-translocase and as a separate entity. Here, we show that the type II IMP FtsQ requires both the translocase and, to a lesser extent, YidC in vivo. Using photo-crosslinking we demonstrate that the transmembrane (TM) domain of the nascent IMP FtsQ inserts into the membrane close to SecY and lipids, and moves to a combined YidC/lipid environment upon elongation. These data are consistent with a crucial role for YidC in the lateral transfer of TM domains from the Sec translocase into the lipid bilayer. |
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