- advanced search

Welcome to ZOMEBase, the information center for the three PCI Zomes: COP9 Signalosome, the regulatory lid of the 26S proteasome and eIF3

What is a ZOME?

A "ZOME" is any one of three related multi-protein complexes:

the Cop9 Signalosome
the Regulatory Lid of the 26S proteasome
eIF3

These complexes were grouped together on the basis of similarities in their subunit composition and predicted structure. While subunits between the complexes share little primary sequence similarity, six subunits of all three complexes contain a PCI (Proteasome, CSN, eIF3) motif, while two subunits carry an MPN (Mpr1, Pad1, N-terminal) motif. This conserved six PCI / two MPN structure (among most higher eukaryotes) strongly suggests a common ancestor for these complexes. (1)

ZOMES, individually and in concert, affect proteome composition.

In ZOMEBase you can find

Want to contribute to ZOMEBase?

All Zomers are welcome and invited to contribute to and modify ZOMEBase using the Twiki editor on each page. To edit, you'll need a username and password. Please contact dannyc@tauex.tau.ac.il . As a contributer you can edit and add to exisiting content including making new pages.

Pages that need to be worked on

ZOMEBase Utilities

Recent ZOMES articles

NCBI: db=pubmed; Term=cop9 or "proteasome lid" or eIF3 or jab1

Virus-mediated compartmentalization of the host translational machinery.

MBio. 2014;5(5)

Authors: Desmet EA, Anguish LJ, Parker JS

Abstract
UNLABELLED: Viruses require the host translational apparatus to synthesize viral proteins. Host stress response mechanisms that suppress translation, therefore, represent a significant obstacle that viruses must overcome. Here, we report a strategy whereby the mammalian orthoreoviruses compartmentalize the translational machinery within virus-induced inclusions known as viral factories (VF). VF are the sites of reovirus replication and assembly but were thought not to contain ribosomes. It was assumed viral mRNAs exited the VF to undergo translation by the cellular machinery, and proteins reentered the factory to participate in assembly. Here, we used ribopuromycylation to visualize active translation in infected cells. These studies revealed that active translation occurs within VF and that ribosomal subunits and proteins required for translation initiation, elongation, termination, and recycling localize to the factory. Interestingly, we observed components of the 43S preinitiation complex (PIC) concentrating primarily at factory margins, suggesting a spatial and/or dynamic organization of translation within the VF. Similarly, the viral single-stranded RNA binding protein σNS localized to the factory margins and had a tubulovesicular staining pattern that extended a short distance from the margins of the factories and colocalized with endoplasmic reticulum (ER) markers. Consistent with these colocalization studies, σNS was found to associate with both eukaryotic translation initiation factor 3 subunit A (eIF3A) and the ribosomal subunit pS6R. Together, these findings indicate that σNS functions to recruit 43S PIC machinery to the primary site of viral translation within the viral factory. Pathogen-mediated compartmentalization of the translational apparatus provides a novel mechanism by which viruses might avoid host translational suppression.
IMPORTANCE: Viruses lack biosynthetic capabilities and depend upon the host for protein synthesis. This dependence requires viruses to evolve mechanisms to coerce the host translational machinery into synthesizing viral proteins in the face of ongoing cellular stress responses that suppress global protein synthesis. Reoviruses replicate and assemble within cytoplasmic inclusions called viral factories. However, synthesis of viral proteins was thought to occur in the cytosol. To identify the site(s) of viral translation, we undertook a microscopy-based approach using ribopuromycylation to detect active translation. Here, we report that active translation occurs within viral factories and that translational factors are compartmentalized within factories. Furthermore, we find that the reovirus nonstructural protein σNS associates with 43S preinitiation complexes at the factory margins, suggesting a role for σNS in translation. Together, virus-induced compartmentalization of the host translational machinery represents a strategy for viruses to spatiotemporally couple viral protein synthesis with viral replication and assembly.

PMID: 25227463 [PubMed - in process]

Notes

1 : Hofmann, K., and Bucher, P. (1998). The pci domain: A common theme in three multi-protein complexes. Trends Biochem Sci 23, 204-205.;Aravind, L., and Ponting, C.P. (1998). Homologues of 26S proteasome subunits are regulators of transcription and translation. Protein Sci 7, 1250-1254.; Kim, T.-H., Hofmann, K., von Arnim, A.G., and Chamovitz, D.A. (2001). The pci complexes:pretty complex interations in diverse signaling pathways. Trend Plant Sciences 6, 379-386.


r21 - 02 Aug 2010 - 12:15:05 - IdoGan
This site is powered by the TWiki collaboration platformCopyright © 2008-2014 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback
Syndicate this site RSSATOM