6e8g

Structural highlights

Function

[IST1_HUMAN] Proposed to be involved in specific functions of the ESCRT machinery. Is required for efficient abscission during cytokinesis, but not for HIV-1 budding. The involvement in the MVB pathway is not established. Involved in recruiting VPS4A and/or VPS4B to the midbody of dividing cells.^{[1] [2]} [CHM1B_HUMAN] Probable peripherally associated component of the endosomal sorting required for transport complex III (ESCRT-III) which is involved in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. MVBs contain intraluminal vesicles (ILVs) that are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids. The MVB pathway appears to require the sequential function of ESCRT-O, -I,-II and -III complexes. ESCRT-III proteins mostly dissociate from the invaginating membrane before the ILV is released. The ESCRT machinery also functions in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis and the budding of enveloped viruses (HIV-1 and other lentiviruses). ESCRT-III proteins are believed to mediate the necessary vesicle extrusion and/or membrane fission activities, possibly in conjunction with the AAA ATPase VPS4. Involved in cytokinesis. Involved in recruiting VPS4A and/or VPS4B and SPAST to the midbody of dividing cells. Involved in HIV-1 p6- and p9-dependent virus release.^{[3] [4]}

See Also

• Charged multivesicular body protein 3D structures

References

1. ↑ Bajorek M, Morita E, Skalicky JJ, Morham SG, Babst M, Sundquist WI. Biochemical analyses of human IST1 and its function in cytokinesis. Mol Biol Cell. 2009 Mar;20(5):1360-73. doi: 10.1091/mbc.E08-05-0475. Epub 2009, Jan 7. PMID:19129479 doi:http://dx.doi.org/10.1091/mbc.E08-05-0475
2. ↑ Agromayor M, Carlton JG, Phelan JP, Matthews DR, Carlin LM, Ameer-Beg S, Bowers K, Martin-Serrano J. Essential role of hIST1 in cytokinesis. Mol Biol Cell. 2009 Mar;20(5):1374-87. doi: 10.1091/mbc.E08-05-0474. Epub 2009, Jan 7. PMID:19129480 doi:http://dx.doi.org/10.1091/mbc.E08-05-0474
3. ↑ Martin-Serrano J, Yarovoy A, Perez-Caballero D, Bieniasz PD. Divergent retroviral late-budding domains recruit vacuolar protein sorting factors by using alternative adaptor proteins. Proc Natl Acad Sci U S A. 2003 Oct 14;100(21):12414-9. Epub 2003 Sep 30. PMID:14519844 doi:10.1073/pnas.2133846100
4. ↑ Bajorek M, Morita E, Skalicky JJ, Morham SG, Babst M, Sundquist WI. Biochemical analyses of human IST1 and its function in cytokinesis. Mol Biol Cell. 2009 Mar;20(5):1360-73. doi: 10.1091/mbc.E08-05-0475. Epub 2009, Jan 7. PMID:19129479 doi:http://dx.doi.org/10.1091/mbc.E08-05-0475