Targeting and translocation of two lipoproteins in Escherichia coli via the SRP/Sec/YidC pathway.
In Escherichia coli, two main protein targeting pathways to the inner membrane exist: the SecB pathway for the essentially posttranslational targeting of secretory proteins and the SRP pathway for cotranslational targeting of inner membrane proteins (IMPs). At the inner membrane both pathways converge at the Sec translocase, which is capable of both linear transport into the periplasm and lateral transport into the lipid bilayer. The Sec-associated YidC appears to assist the lateral transport of IMPs from the Sec translocase into the lipid bilayer. It should be noted that targeting and translocation of only a handful of secretory proteins and IMPs have been studied. These model proteins do not include lipoproteins. Here, we have studied the targeting and translocation of two secretory lipoproteins, the murein lipoprotein and the bacteriocin release protein, using a combined in vivo and in vitro approach. The data indicate that both murein lipoprotein and bacteriocin release protein require the SRP pathway for efficient targeting to the Sec translocase. Furthermore, we show that YidC plays an important role in the targeting/translocation of both lipoproteins.
Fröderberg
Linda
L
Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, SE-106 91 Stockholm, Sweden.
Houben
Edith N G
EN
Baars
Louise
L
Luirink
Joen
J
de Gier
Jan-Willem
JW
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001430:Bacteriocins / Q000378:metabolism; D003432:Cross-Linking Reagents; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D000069816:SEC Translocation Channels; D000081416:SecA Proteins; D017386:Sequence Homology, Amino Acid; D018271:Signal Recognition Particle / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D001430:Bacteriocins; D003432:Cross-Linking Reagents; D029968:Escherichia coli Proteins; D008074:Lipoproteins; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; D018271:Signal Recognition Particle; C412443:YIDC protein, E coli; C052368:cloacin DF13-encoded bacteriocin release protein, E coli; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins