The Sec61p complex is a dynamic precursor activated channel.
Previous studies have shown that the rough endoplasmic reticulum (ER) contains nascent precursor polypeptide gated channels. Circumstantial evidence suggests that these channels are formed by the Sec61p complex. We reconstituted the purified Sec61p complex in a lipid bilayer and characterized its dynamics and regulation. The Sec61p complex is sufficient to form the precursor polypeptide activated channel under co- and posttranslational transport conditions. Activity of the Sec61p channel in both transport modes is induced by direct interaction with precursor protein. The Sec61p complex comprises a highly dynamic pore covering conductances corresponding to channel openings from approximately 6 to 60 A. Its properties are indistinguishable from those we observed with native ER channels, directly demonstrating that these channels are formed by the Sec61p complex.
Wirth
Andreas
A
Biophysik, Universität Osnabrück, FB Biologie/Chemie, D-49034 Osnabrück, Germany.
Jung
Martin
M
Bies
Christiane
C
Frien
Michael
M
Tyedmers
Jens
J
Zimmermann
Richard
R
Wagner
Richard
R
D036002:ADP Ribose Transferases / Q000494:pharmacology; D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism / Q000494:pharmacology; D000091342:Endoplasmic Reticulum Chaperone BiP; D018870:Endoplasmic Reticulum, Rough / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000378:metabolism*; D005098:Exotoxins / Q000494:pharmacology; D006360:Heat-Shock Proteins; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism / Q000494:pharmacology; D015394:Molecular Structure; D010455:Peptides / Q000378:metabolism; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational / Q000502:physiology; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology*; D000069816:SEC Translocation Channels; D037521:Virulence Factors / Q000494:pharmacology; D000097668:Pseudomonas aeruginosa Exotoxin A
D036002:ADP Ribose Transferases; D001427:Bacterial Toxins; D002352:Carrier Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D005098:Exotoxins; D006360:Heat-Shock Proteins; D007473:Ion Channels; D046911:Macromolecular Substances; D008565:Membrane Proteins; D018832:Molecular Chaperones; D010455:Peptides; D000069816:SEC Translocation Channels; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A