Send to

Choose Destination
Cell. 2000 Jul 21;102(2):233-44.

The Sec61p complex mediates the integration of a membrane protein by allowing lipid partitioning of the transmembrane domain.

Author information

Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.


We have investigated how the transmembrane (TM) domain of a membrane protein is cotranslationally integrated into the endoplasmic reticulum. We demonstrate that the Sec61p channel allows the TM domain to bypass the barrier posed by the polar head groups of the lipid bilayer and come into contact with the hydrophobic interior of the membrane. Together with the TRAM protein, Sec61p provides a site in the membrane, at the interface of channel and lipid, through which a TM domain can dynamically equilibrate between the lipid and aqueous phases, depending on the hydrophobicity of the TM domain and the length of the polypeptide segment tethering it to the ribosome. Our results suggest a unifying, lipid-partitioning model which can explain the general behavior of hydrophobic topogenic sequences.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center