ESCRT III kompleksin molekyylit CHMP

 CHMP1A (Kr.16q24.3)

https://www.ncbi.nlm.nih.gov/protein/NP_001076783.1

PCH8; CHMP1; PRSM1; PCOLN3; VPS46A; VPS46-1

Summary This gene encodes a member of the CHMP/Chmp family of proteins which are involved in multivesicular body sorting of proteins to the interiors of lysosomes. The initial prediction (1996)  of the protein sequence encoded by this gene suggested that the encoded protein was a metallopeptidase. The nomenclature has been updated recently to reflect the correct biological function of this encoded protein. Several transcripts encoding different isoforms have been found for this gene. [provided by RefSeq, Dec 2012]

CHMP1B (Kr. 18p11.21)

https://www.ncbi.nlm.nih.gov/gene/57132

Vps46B; C10orf2; C18orf2; CHMP1.5; Vps46-2; C18-ORF2; hVps46-2

Summary  CHMP1B belongs to the chromatin-modifying protein/charged multivesicular body protein (CHMP) family. These proteins are components of ESCRT-III (endosomal sorting complex required for transport III), a complex involved in degradation of surface receptor proteins and formation of endocytic multivesicular bodies (MVBs). Some CHMPs have both nuclear and cytoplasmic/vesicular distributions, and one such CHMP, CHMP1A (MIM 164010), is required for both MVB formation and regulation of cell cycle progression (Tsang et al., 2006 [PubMed 16730941]).[supplied by OMIM, Mar 2008]

 

Science. 2015 Dec 18;350(6267):1548-51. doi: 10.1126/science.aad8305. Epub 2015 Dec 3.

Structure and membrane remodeling activity of ESCRT-III helical polymers.McCullough J¹, Clippinger AK², Talledge N³, Skowyra ML², Saunders MG¹, Naismith TV², Colf LA¹, Afonine P⁴, Arthur C⁵, Sundquist WI⁶, Hanson PI⁷, Frost A⁸.
Abstract

The endosomal sorting complexes required for transport (ESCRT) proteins mediate fundamental membrane remodeling events that require stabilizing negative membrane curvature. These include endosomal intralumenal vesicle formation, HIV budding, nuclear envelope closure, and cytokinetic abscission. ESCRT-III subunits perform key roles in these processes by changing conformation and polymerizing into membrane-remodeling filaments. Here, we report the 4 angstrom resolution cryogenic electron microscopy reconstruction of a one-start, double-stranded helical copolymer composed of two different human ESCRT-III subunits, charged multivesicular body protein 1B (CHMP1B) and increased sodium tolerance 1 (IST1). The inner strand comprises "open" CHMP1B subunits that interlock in an elaborate domain-swapped architecture and is encircled by an outer strand of "closed" IST1 subunits. Unlike other ESCRT-III proteins, CHMP1B and IST1 polymers form external coats on positively curved membranes in vitro and in vivo. Our analysis suggests how common ESCRT-III filament architectures could stabilize different degrees and directions of membrane curvature.

IST-1-CHMP1B ESCRT-III Copolymer

 

https://www.sciencedirect.com/science/article/pii/S0955067415001441#fig0010

Ongelma sinänsä ei ole tässä evolutionaalisesti  varmalla pohjalla olevassa kopolymeraatiossapitkän spiraalifilamentin  muodostamisess, vaan sen sijaan  osasten hyödyntämisessä, sillä  dynaaminen "lego"- muodostelma pitää voida  yhtä  äkkiä purkaa ja  osat kierrättää uudestaan isäntäkehossa. 
 Esim EBOV näyttää saavan tällä järjestelmällä oiken pitkän talvisukan kudottua  virioninsa tulevaiseksi vahvuudeksi. HIV-1 tyytyy pieniin pallukoihin.
Alla olevassa lähteessä mainitaan myös RSV-virus.

Kipper S, Hamad S, Caly L, Avrahami D, Bacharach E, Jans DA, Gerber
            D and Bajorek M.
  TITLE     New host factors important for respiratory syncytial virus (RSV)
            replication revealed by a novel microfluidics screen for
            interactors of matrix (M) protein
  JOURNAL   Mol. Cell Proteomics 14 (3), 532-543 (2015)

 
 https://www.ncbi.nlm.nih.gov/protein/NP_065145.2