Translocon

The translocon (also known as a translocator or translocation channel) is a complex of proteins associated with the translocation of polypeptides across membranes.[1] In eukaryotes the term translocon most commonly refers to the complex that transports nascent polypeptides with a targeting signal sequence into the interior (cisternal or lumenal) space of the endoplasmic reticulum (ER) from the cytosol. This translocation process requires the protein to cross a hydrophobic lipid bilayer. The same complex is also used to integrate nascent proteins into the membrane itself (membrane proteins). In prokaryotes, a similar protein complex transports polypeptides across the (inner) plasma membrane or integrates membrane proteins.[2] In either case, the protein complex are formed from Sec proteins (Sec: secretory), with the heterotrimeric Sec61 being the channel.[3] In prokaryotes, the homologous channel complex is known as SecYEG.[4]

This article focuses on the cell's native translocons, but pathogens can also assemble other translocons in their host membranes, allowing them to export virulence factors into their target cells.[5]

  1. ^ Johnson AE, van Waes MA (1999). "The translocon: a dynamic gateway at the ER membrane". Annual Review of Cell and Developmental Biology. 15: 799–842. doi:10.1146/annurev.cellbio.15.1.799. PMID 10611978.
  2. ^ Gold VA, Duong F, Collinson I (2007). "Structure and function of the bacterial Sec translocon". Molecular Membrane Biology. 24 (5–6): 387–94. doi:10.1080/09687680701416570. PMID 17710643. S2CID 83946219.
  3. ^ Deshaies RJ, Sanders SL, Feldheim DA, Schekman R (February 1991). "Assembly of yeast Sec proteins involved in translocation into the endoplasmic reticulum into a membrane-bound multisubunit complex". Nature. 349 (6312): 806–8. Bibcode:1991Natur.349..806D. doi:10.1038/349806a0. PMID 2000150. S2CID 31383053.
  4. ^ Cite error: The named reference VandenBerg was invoked but never defined (see the help page).
  5. ^ Mueller CA, Broz P, Cornelis GR (June 2008). "The type III secretion system tip complex and translocon". Molecular Microbiology. 68 (5): 1085–95. doi:10.1111/j.1365-2958.2008.06237.x. PMID 18430138. S2CID 205366024.