The Translocon: A Dynamic Gateway at the ER Membrane
- 1 November 1999
- journal article
- review article
- Published by Annual Reviews in Annual Review of Cell and Developmental Biology
- Vol. 15 (1), 799-842
- https://doi.org/10.1146/annurev.cellbio.15.1.799
Abstract
▪ Abstract Cotranslational protein translocation across and integration into the membrane of the endoplasmic reticulum (ER) occur at sites termed translocons. Translocons are composed of several ER membrane proteins that associate to form an aqueous pore through which secretory proteins and lumenal domains of membrane proteins pass from the cytoplasm to the ER lumen. These sites are not passive holes in the bilayer, but instead are quite dynamic both structurally and functionally. Translocons cycle between ribosome-bound and ribosome-free states, and convert between translocation and integration modes of operation. These changes in functional state are accompanied by structural rearrangements that alter translocon conformation, composition, and interactions with ligands such as the ribosome and BiP. Recent studies have revealed that the translocon is a complex and sophisticated molecular machine that regulates the movement of polypeptides through the bilayer, apparently in both directions as well as laterally into the bilayer, all while maintaining the membrane permeability barrier.Keywords
This publication has 82 references indexed in Scilit:
- The Protein Import Motor of Mitochondria: Unfolding and Trapping of Preproteins Are Distinct and Separable Functions of Matrix Hsp70Cell, 1999
- The bacterial SecY/E translocation complex forms channel-like structures similar to those of the eukaryotic sec61p complexJournal of Molecular Biology, 1999
- Regulation by the ribosome of the GTPase of the signal-recognition particle during protein targetingNature, 1996
- Ubiquitin-Proteasome Pathway Mediates Intracellular Degradation of Apolipoprotein BBiochemistry, 1996
- Heads or tails — what determines the orientation of proteins in the membraneFEBS Letters, 1995
- Can Hsp70 proteins act as force-generating motors?Cell, 1995
- GTP binding and hydrolysis by the signal recognition particle during initiation of protein translocationNature, 1993
- A protein translocation defect linked to ubiquitin conjugation at the endoplasmic reticulumNature, 1993
- Pause transfer: A topogenic sequence in apolipoprotein B mediates stopping and restarting of translocationCell, 1992
- Photocrosslinking demonstrates proximity of a 34 kDa membrane protein to different portions of preprolactin during translocation through the endoplasmic reticulumFEBS Letters, 1989