ESCRT

The endosomal sorting complexes required for transport (ESCRT) machinery is made up of cytosolic protein complexes, known as ESCRT-0, ESCRT-I, ESCRT-II, and ESCRT-III. Together with a number of accessory proteins, these ESCRT complexes enable a unique mode of membrane remodeling that results in membranes bending/budding away from the cytoplasm.[1][2] These ESCRT components have been isolated and studied in a number of organisms including yeast and humans.[3] A eukaryotic signature protein, the machinery is found in all eukaryotes and some archaea.[4]

The ESCRT machinery plays a vital role in a number of cellular processes including multivesicular body (MVB) biogenesis, cellular abscission, and viral budding. Multivesicular body (MVB) biogenesis is a process in which ubiquitin-tagged proteins enter organelles called endosomes via the formation of vesicles. This process is essential for cells to destroy misfolded and damaged proteins.[5] Without ESCRT machinery, these proteins can build up and lead to neurodegenerative disease. For example, abnormalities in ESCRT-III components can lead to neurological disorders such as hereditary spastic paraplegia (HSP).[6] Cellular abscission, the process by which the membrane connecting two daughter cells is cleaved, is also mediated by ESCRT machinery. Without the ESCRT complexes, daughter cells could not separate and abnormal cells containing twice the amount of DNA would be generated. These cells would inevitably be destroyed through a process known as apoptosis. Lastly, viral budding, or the process by which specific types of viruses exit cells, may not occur in the absence of ESCRT machinery. This would inevitably prevent viruses from spreading from cell to cell.

  1. ^ Schmidt O, Teis D (February 2012). "The ESCRT machinery". Curr. Biol. 22 (4): R116–20. doi:10.1016/j.cub.2012.01.028. PMC 3314914. PMID 22361144.
  2. ^ Babst M (August 2011). "MVB vesicle formation: ESCRT-dependent, ESCRT-independent and everything in between". Curr. Opin. Cell Biol. 23 (4): 452–7. doi:10.1016/j.ceb.2011.04.008. PMC 3148405. PMID 21570275.
  3. ^ Hurley JH, Hanson PI (August 2010). "Membrane budding and scission by the ESCRT machinery: it's all in the neck". Nat. Rev. Mol. Cell Biol. 11 (8): 556–66. doi:10.1038/nrm2937. PMC 2922035. PMID 20588296.
  4. ^ Samson, RY; Dobro, MJ; Jensen, GJ; Bell, SD (2017). "The Structure, Function and Roles of the Archaeal ESCRT Apparatus". Prokaryotic Cytoskeletons. Subcellular Biochemistry. Vol. 84. pp. 357–377. doi:10.1007/978-3-319-53047-5_12. ISBN 978-3-319-53045-1. PMID 28500532.
  5. ^ Cite error: The named reference piper was invoked but never defined (see the help page).
  6. ^ Hurley JH (December 2010). "The ESCRT complexes". Crit. Rev. Biochem. Mol. Biol. 45 (6): 463–87. doi:10.3109/10409238.2010.502516. PMC 2988974. PMID 20653365.