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onsdag 16 maj 2018

VPS4 (Kr.16q22.1) SKD1, SKD1A, (ATPaasi, ESCRT-III liittynyt )

 

VPS4 (Kr.16q22.1)

VPS4:n osuus exosomin abskissiossa , kun ESCRT-II on saanut valmiiksi pakattua exosomaalisen pussin. Abscissio vaihe, josta voidaan sitten hajoitaa rakenteelliset ESCRT- tekijät hyödynnyskiertoon, kuten normaalissa mitoosi-sytokineesi transitiossa
 mutta  virukset, jotka hyödyntävät  tätä sytokinetiikkaa, voivat pakata  ESCRT- tekijöitä ja tätäkin VSP4.ää  virioniin mukaan
Löysin  kaavakuvan VSP-n asemasta ESCRT-III  taphtumien  jatkossa.
Taphtuu VSP4 monomeerien koostuminen VSP-oligomeeriksi,  interaktio ESCRT-tekijöiden kanssa ja ESCRT-II disassembly,  tekijöiden erkaneminen. ja exosomin abskissio, erotus. Abskissiotapahtumassa ESCRT-III:n  puolelta CHMP4B ja  VPS4 puolelta VPS4A tekevät  interaktion, joka ajallisesti ja tilavuudellisesti korreloi abskissioon  joka siinä samassa on tapahtunut.

https://openi.nlm.nih.gov/detailedresult.php?img=PMC3314914_gr3&req=4
 Membrane scission and ESCRT-III disassembly by Vps4.The ESCRT-III subunits Vps24 and Vps2 terminate assembly of the ESCRT-III filament (orange) on the endosome surface. Vps2 together with Did2, Ist1 and Vps60 build a recruitment complex for the AAA-ATPase Vps4 and its cofactor Vta1. Once assembled, the Vps4 complex (pink) catalyzes disassembly of the ESCRT-III filament in an ATP-driven reaction. ESCRT-III disassembly terminates each round of the MVB pathway, which results in the generation of a cargo-laden 25 nm MVB vesicle (50 nm in human cells).



Human VPS4 gene
https://www.ncbi.nlm.nih.gov/gene/27183
Preferred Names
vacuolar protein sorting-associated protein 4A
Names
SKD1-homolog
hVPS4
vacuolar protein sorting factor 4A
vacuolar sorting protein 
Also known as
SKD1; SKD2; VPS4; SKD1A; VPS4-1
Kyse on ATPaasientsyymistä, sillä abskissiotapahtuma vaatii energiaa. 


 RAKENNE ( peptidisekvenssi)

https://www.ncbi.nlm.nih.gov/protein/NP_037377.1

Huom. AMSH  (JAMM,  DUB deubikitinaasi )   (Associated molecule with SH3 domain of STAM)
on ESCRT-II:een assosioitunut entsyymi ja se kilpailee VPS4:n kanssa sitoutumisesta  CHMP1A:n ja CHMPiB:n C-terminaalisiin alueihin
http://www.jbc.org/content/281/32/23083
2006 Aug 11;281(32):23083-91. Epub 2006 Jun 7.

Interaction of AMSH with ESCRT-III and deubiquitination of endosomal cargo.

The "class E" vacuolar protein sorting (VPS) pathway mediates sorting of ubiquitinated cargo into the forming vesicles of the multivesicular bodies (MVB), and it is essential for down-regulation of signaling by growth factors and budding of enveloped viruses such as Ebola and HIV-1. Work in yeast has identified DOA4 as a gene that is recruited by the class E machinery to remove ubiquitin from the endosomal cargo before it is incorporated into MVB vesicles, but the identity of the mammalian counterpart is unclear. Here we report the interaction of AMSH (associated molecule with the SH3 domain of STAM), an endosomal deubiquitinating enzyme, with the endosomal sorting complex required for transport (ESCRT-III) subunits CHMP1A, CHMP1B, CHMP2A, and CHMP3. We also show that a catalytically inactive AMSH inhibits retroviral budding in a dominant-negative manner and induces the accumulation of ubiquitinated forms of an endosomal cargo, namely murine leukemia virus Gag. Finally, VPS4 and AMSH compete for binding to the C-terminal regions of CHMP1A and CHMP1B, revealing a coordinated interaction with ESCRT-III. Taken together, these results are consistent with a role of AMSH in the deubiquitination of the endosomal cargo preceding lysosomal degradation.
PMID:
16760479
DOI:
10.1074/jbc.M513803200

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